1677 lines
60 KiB
C++
1677 lines
60 KiB
C++
//===--- CGStmt.cpp - Emit LLVM Code from Statements ----------------------===//
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//
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// The LLVM Compiler Infrastructure
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//
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// This file is distributed under the University of Illinois Open Source
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// License. See LICENSE.TXT for details.
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//
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//===----------------------------------------------------------------------===//
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//
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// This contains code to emit Stmt nodes as LLVM code.
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//
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//===----------------------------------------------------------------------===//
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#include "CGDebugInfo.h"
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#include "CodeGenModule.h"
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#include "CodeGenFunction.h"
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#include "TargetInfo.h"
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#include "clang/AST/StmtVisitor.h"
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#include "clang/Basic/PrettyStackTrace.h"
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#include "clang/Basic/TargetInfo.h"
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#include "llvm/ADT/StringExtras.h"
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#include "llvm/InlineAsm.h"
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#include "llvm/Intrinsics.h"
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#include "llvm/Target/TargetData.h"
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using namespace clang;
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using namespace CodeGen;
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//===----------------------------------------------------------------------===//
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// Statement Emission
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//===----------------------------------------------------------------------===//
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void CodeGenFunction::EmitStopPoint(const Stmt *S) {
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if (CGDebugInfo *DI = getDebugInfo()) {
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SourceLocation Loc;
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if (isa<DeclStmt>(S))
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Loc = S->getLocEnd();
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else
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Loc = S->getLocStart();
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DI->EmitLocation(Builder, Loc);
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}
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}
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void CodeGenFunction::EmitStmt(const Stmt *S) {
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assert(S && "Null statement?");
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// These statements have their own debug info handling.
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if (EmitSimpleStmt(S))
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return;
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// Check if we are generating unreachable code.
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if (!HaveInsertPoint()) {
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// If so, and the statement doesn't contain a label, then we do not need to
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// generate actual code. This is safe because (1) the current point is
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// unreachable, so we don't need to execute the code, and (2) we've already
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// handled the statements which update internal data structures (like the
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// local variable map) which could be used by subsequent statements.
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if (!ContainsLabel(S)) {
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// Verify that any decl statements were handled as simple, they may be in
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// scope of subsequent reachable statements.
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assert(!isa<DeclStmt>(*S) && "Unexpected DeclStmt!");
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return;
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}
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// Otherwise, make a new block to hold the code.
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EnsureInsertPoint();
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}
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// Generate a stoppoint if we are emitting debug info.
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EmitStopPoint(S);
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switch (S->getStmtClass()) {
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case Stmt::NoStmtClass:
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case Stmt::CXXCatchStmtClass:
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case Stmt::SEHExceptStmtClass:
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case Stmt::SEHFinallyStmtClass:
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case Stmt::MSDependentExistsStmtClass:
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llvm_unreachable("invalid statement class to emit generically");
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case Stmt::NullStmtClass:
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case Stmt::CompoundStmtClass:
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case Stmt::DeclStmtClass:
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case Stmt::LabelStmtClass:
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case Stmt::GotoStmtClass:
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case Stmt::BreakStmtClass:
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case Stmt::ContinueStmtClass:
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case Stmt::DefaultStmtClass:
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case Stmt::CaseStmtClass:
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llvm_unreachable("should have emitted these statements as simple");
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#define STMT(Type, Base)
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#define ABSTRACT_STMT(Op)
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#define EXPR(Type, Base) \
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case Stmt::Type##Class:
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#include "clang/AST/StmtNodes.inc"
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{
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// Remember the block we came in on.
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llvm::BasicBlock *incoming = Builder.GetInsertBlock();
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assert(incoming && "expression emission must have an insertion point");
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EmitIgnoredExpr(cast<Expr>(S));
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llvm::BasicBlock *outgoing = Builder.GetInsertBlock();
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assert(outgoing && "expression emission cleared block!");
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// The expression emitters assume (reasonably!) that the insertion
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// point is always set. To maintain that, the call-emission code
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// for noreturn functions has to enter a new block with no
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// predecessors. We want to kill that block and mark the current
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// insertion point unreachable in the common case of a call like
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// "exit();". Since expression emission doesn't otherwise create
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// blocks with no predecessors, we can just test for that.
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// However, we must be careful not to do this to our incoming
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// block, because *statement* emission does sometimes create
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// reachable blocks which will have no predecessors until later in
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// the function. This occurs with, e.g., labels that are not
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// reachable by fallthrough.
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if (incoming != outgoing && outgoing->use_empty()) {
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outgoing->eraseFromParent();
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Builder.ClearInsertionPoint();
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}
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break;
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}
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case Stmt::IndirectGotoStmtClass:
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EmitIndirectGotoStmt(cast<IndirectGotoStmt>(*S)); break;
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case Stmt::IfStmtClass: EmitIfStmt(cast<IfStmt>(*S)); break;
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case Stmt::WhileStmtClass: EmitWhileStmt(cast<WhileStmt>(*S)); break;
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case Stmt::DoStmtClass: EmitDoStmt(cast<DoStmt>(*S)); break;
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case Stmt::ForStmtClass: EmitForStmt(cast<ForStmt>(*S)); break;
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case Stmt::ReturnStmtClass: EmitReturnStmt(cast<ReturnStmt>(*S)); break;
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case Stmt::SwitchStmtClass: EmitSwitchStmt(cast<SwitchStmt>(*S)); break;
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case Stmt::AsmStmtClass: EmitAsmStmt(cast<AsmStmt>(*S)); break;
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case Stmt::ObjCAtTryStmtClass:
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EmitObjCAtTryStmt(cast<ObjCAtTryStmt>(*S));
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break;
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case Stmt::ObjCAtCatchStmtClass:
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llvm_unreachable(
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"@catch statements should be handled by EmitObjCAtTryStmt");
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case Stmt::ObjCAtFinallyStmtClass:
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llvm_unreachable(
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"@finally statements should be handled by EmitObjCAtTryStmt");
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case Stmt::ObjCAtThrowStmtClass:
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EmitObjCAtThrowStmt(cast<ObjCAtThrowStmt>(*S));
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break;
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case Stmt::ObjCAtSynchronizedStmtClass:
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EmitObjCAtSynchronizedStmt(cast<ObjCAtSynchronizedStmt>(*S));
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break;
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case Stmt::ObjCForCollectionStmtClass:
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EmitObjCForCollectionStmt(cast<ObjCForCollectionStmt>(*S));
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break;
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case Stmt::ObjCAutoreleasePoolStmtClass:
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EmitObjCAutoreleasePoolStmt(cast<ObjCAutoreleasePoolStmt>(*S));
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break;
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case Stmt::CXXTryStmtClass:
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EmitCXXTryStmt(cast<CXXTryStmt>(*S));
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break;
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case Stmt::CXXForRangeStmtClass:
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EmitCXXForRangeStmt(cast<CXXForRangeStmt>(*S));
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case Stmt::SEHTryStmtClass:
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// FIXME Not yet implemented
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break;
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}
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}
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bool CodeGenFunction::EmitSimpleStmt(const Stmt *S) {
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switch (S->getStmtClass()) {
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default: return false;
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case Stmt::NullStmtClass: break;
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case Stmt::CompoundStmtClass: EmitCompoundStmt(cast<CompoundStmt>(*S)); break;
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case Stmt::DeclStmtClass: EmitDeclStmt(cast<DeclStmt>(*S)); break;
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case Stmt::LabelStmtClass: EmitLabelStmt(cast<LabelStmt>(*S)); break;
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case Stmt::GotoStmtClass: EmitGotoStmt(cast<GotoStmt>(*S)); break;
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case Stmt::BreakStmtClass: EmitBreakStmt(cast<BreakStmt>(*S)); break;
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case Stmt::ContinueStmtClass: EmitContinueStmt(cast<ContinueStmt>(*S)); break;
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case Stmt::DefaultStmtClass: EmitDefaultStmt(cast<DefaultStmt>(*S)); break;
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case Stmt::CaseStmtClass: EmitCaseStmt(cast<CaseStmt>(*S)); break;
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}
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return true;
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}
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/// EmitCompoundStmt - Emit a compound statement {..} node. If GetLast is true,
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/// this captures the expression result of the last sub-statement and returns it
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/// (for use by the statement expression extension).
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RValue CodeGenFunction::EmitCompoundStmt(const CompoundStmt &S, bool GetLast,
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AggValueSlot AggSlot) {
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PrettyStackTraceLoc CrashInfo(getContext().getSourceManager(),S.getLBracLoc(),
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"LLVM IR generation of compound statement ('{}')");
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// Keep track of the current cleanup stack depth, including debug scopes.
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LexicalScope Scope(*this, S.getSourceRange());
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for (CompoundStmt::const_body_iterator I = S.body_begin(),
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E = S.body_end()-GetLast; I != E; ++I)
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EmitStmt(*I);
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RValue RV;
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if (!GetLast)
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RV = RValue::get(0);
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else {
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// We have to special case labels here. They are statements, but when put
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// at the end of a statement expression, they yield the value of their
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// subexpression. Handle this by walking through all labels we encounter,
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// emitting them before we evaluate the subexpr.
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const Stmt *LastStmt = S.body_back();
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while (const LabelStmt *LS = dyn_cast<LabelStmt>(LastStmt)) {
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EmitLabel(LS->getDecl());
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LastStmt = LS->getSubStmt();
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}
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EnsureInsertPoint();
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RV = EmitAnyExpr(cast<Expr>(LastStmt), AggSlot);
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}
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return RV;
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}
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void CodeGenFunction::SimplifyForwardingBlocks(llvm::BasicBlock *BB) {
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llvm::BranchInst *BI = dyn_cast<llvm::BranchInst>(BB->getTerminator());
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// If there is a cleanup stack, then we it isn't worth trying to
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// simplify this block (we would need to remove it from the scope map
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// and cleanup entry).
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if (!EHStack.empty())
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return;
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// Can only simplify direct branches.
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if (!BI || !BI->isUnconditional())
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return;
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BB->replaceAllUsesWith(BI->getSuccessor(0));
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BI->eraseFromParent();
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BB->eraseFromParent();
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}
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void CodeGenFunction::EmitBlock(llvm::BasicBlock *BB, bool IsFinished) {
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llvm::BasicBlock *CurBB = Builder.GetInsertBlock();
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// Fall out of the current block (if necessary).
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EmitBranch(BB);
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if (IsFinished && BB->use_empty()) {
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delete BB;
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return;
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}
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// Place the block after the current block, if possible, or else at
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// the end of the function.
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if (CurBB && CurBB->getParent())
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CurFn->getBasicBlockList().insertAfter(CurBB, BB);
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else
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CurFn->getBasicBlockList().push_back(BB);
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Builder.SetInsertPoint(BB);
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}
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void CodeGenFunction::EmitBranch(llvm::BasicBlock *Target) {
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// Emit a branch from the current block to the target one if this
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// was a real block. If this was just a fall-through block after a
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// terminator, don't emit it.
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llvm::BasicBlock *CurBB = Builder.GetInsertBlock();
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if (!CurBB || CurBB->getTerminator()) {
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// If there is no insert point or the previous block is already
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// terminated, don't touch it.
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} else {
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// Otherwise, create a fall-through branch.
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Builder.CreateBr(Target);
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}
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Builder.ClearInsertionPoint();
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}
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void CodeGenFunction::EmitBlockAfterUses(llvm::BasicBlock *block) {
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bool inserted = false;
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for (llvm::BasicBlock::use_iterator
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i = block->use_begin(), e = block->use_end(); i != e; ++i) {
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if (llvm::Instruction *insn = dyn_cast<llvm::Instruction>(*i)) {
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CurFn->getBasicBlockList().insertAfter(insn->getParent(), block);
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inserted = true;
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break;
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}
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}
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if (!inserted)
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CurFn->getBasicBlockList().push_back(block);
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Builder.SetInsertPoint(block);
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}
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CodeGenFunction::JumpDest
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CodeGenFunction::getJumpDestForLabel(const LabelDecl *D) {
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JumpDest &Dest = LabelMap[D];
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if (Dest.isValid()) return Dest;
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// Create, but don't insert, the new block.
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Dest = JumpDest(createBasicBlock(D->getName()),
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EHScopeStack::stable_iterator::invalid(),
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NextCleanupDestIndex++);
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return Dest;
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}
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void CodeGenFunction::EmitLabel(const LabelDecl *D) {
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JumpDest &Dest = LabelMap[D];
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// If we didn't need a forward reference to this label, just go
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// ahead and create a destination at the current scope.
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if (!Dest.isValid()) {
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Dest = getJumpDestInCurrentScope(D->getName());
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// Otherwise, we need to give this label a target depth and remove
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// it from the branch-fixups list.
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} else {
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assert(!Dest.getScopeDepth().isValid() && "already emitted label!");
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Dest = JumpDest(Dest.getBlock(),
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EHStack.stable_begin(),
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Dest.getDestIndex());
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ResolveBranchFixups(Dest.getBlock());
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}
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EmitBlock(Dest.getBlock());
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}
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void CodeGenFunction::EmitLabelStmt(const LabelStmt &S) {
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EmitLabel(S.getDecl());
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EmitStmt(S.getSubStmt());
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}
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void CodeGenFunction::EmitGotoStmt(const GotoStmt &S) {
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// If this code is reachable then emit a stop point (if generating
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// debug info). We have to do this ourselves because we are on the
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// "simple" statement path.
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if (HaveInsertPoint())
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EmitStopPoint(&S);
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EmitBranchThroughCleanup(getJumpDestForLabel(S.getLabel()));
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}
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void CodeGenFunction::EmitIndirectGotoStmt(const IndirectGotoStmt &S) {
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if (const LabelDecl *Target = S.getConstantTarget()) {
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EmitBranchThroughCleanup(getJumpDestForLabel(Target));
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return;
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}
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// Ensure that we have an i8* for our PHI node.
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llvm::Value *V = Builder.CreateBitCast(EmitScalarExpr(S.getTarget()),
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Int8PtrTy, "addr");
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llvm::BasicBlock *CurBB = Builder.GetInsertBlock();
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// Get the basic block for the indirect goto.
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llvm::BasicBlock *IndGotoBB = GetIndirectGotoBlock();
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// The first instruction in the block has to be the PHI for the switch dest,
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// add an entry for this branch.
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cast<llvm::PHINode>(IndGotoBB->begin())->addIncoming(V, CurBB);
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EmitBranch(IndGotoBB);
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}
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void CodeGenFunction::EmitIfStmt(const IfStmt &S) {
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// C99 6.8.4.1: The first substatement is executed if the expression compares
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// unequal to 0. The condition must be a scalar type.
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RunCleanupsScope ConditionScope(*this);
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if (S.getConditionVariable())
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EmitAutoVarDecl(*S.getConditionVariable());
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// If the condition constant folds and can be elided, try to avoid emitting
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// the condition and the dead arm of the if/else.
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bool CondConstant;
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if (ConstantFoldsToSimpleInteger(S.getCond(), CondConstant)) {
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// Figure out which block (then or else) is executed.
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const Stmt *Executed = S.getThen();
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const Stmt *Skipped = S.getElse();
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if (!CondConstant) // Condition false?
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std::swap(Executed, Skipped);
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// If the skipped block has no labels in it, just emit the executed block.
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// This avoids emitting dead code and simplifies the CFG substantially.
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if (!ContainsLabel(Skipped)) {
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if (Executed) {
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RunCleanupsScope ExecutedScope(*this);
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EmitStmt(Executed);
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}
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return;
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}
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}
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// Otherwise, the condition did not fold, or we couldn't elide it. Just emit
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// the conditional branch.
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llvm::BasicBlock *ThenBlock = createBasicBlock("if.then");
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llvm::BasicBlock *ContBlock = createBasicBlock("if.end");
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llvm::BasicBlock *ElseBlock = ContBlock;
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if (S.getElse())
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ElseBlock = createBasicBlock("if.else");
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EmitBranchOnBoolExpr(S.getCond(), ThenBlock, ElseBlock);
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// Emit the 'then' code.
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EmitBlock(ThenBlock);
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{
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RunCleanupsScope ThenScope(*this);
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EmitStmt(S.getThen());
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}
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EmitBranch(ContBlock);
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// Emit the 'else' code if present.
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if (const Stmt *Else = S.getElse()) {
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// There is no need to emit line number for unconditional branch.
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if (getDebugInfo())
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Builder.SetCurrentDebugLocation(llvm::DebugLoc());
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EmitBlock(ElseBlock);
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{
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RunCleanupsScope ElseScope(*this);
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EmitStmt(Else);
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}
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// There is no need to emit line number for unconditional branch.
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if (getDebugInfo())
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Builder.SetCurrentDebugLocation(llvm::DebugLoc());
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EmitBranch(ContBlock);
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}
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// Emit the continuation block for code after the if.
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EmitBlock(ContBlock, true);
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}
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void CodeGenFunction::EmitWhileStmt(const WhileStmt &S) {
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// Emit the header for the loop, which will also become
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// the continue target.
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JumpDest LoopHeader = getJumpDestInCurrentScope("while.cond");
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EmitBlock(LoopHeader.getBlock());
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// Create an exit block for when the condition fails, which will
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// also become the break target.
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JumpDest LoopExit = getJumpDestInCurrentScope("while.end");
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// Store the blocks to use for break and continue.
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BreakContinueStack.push_back(BreakContinue(LoopExit, LoopHeader));
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// C++ [stmt.while]p2:
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// When the condition of a while statement is a declaration, the
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// scope of the variable that is declared extends from its point
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// of declaration (3.3.2) to the end of the while statement.
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// [...]
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// The object created in a condition is destroyed and created
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// with each iteration of the loop.
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RunCleanupsScope ConditionScope(*this);
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if (S.getConditionVariable())
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EmitAutoVarDecl(*S.getConditionVariable());
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// Evaluate the conditional in the while header. C99 6.8.5.1: The
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// evaluation of the controlling expression takes place before each
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// execution of the loop body.
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llvm::Value *BoolCondVal = EvaluateExprAsBool(S.getCond());
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// while(1) is common, avoid extra exit blocks. Be sure
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// to correctly handle break/continue though.
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bool EmitBoolCondBranch = true;
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if (llvm::ConstantInt *C = dyn_cast<llvm::ConstantInt>(BoolCondVal))
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if (C->isOne())
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EmitBoolCondBranch = false;
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// As long as the condition is true, go to the loop body.
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llvm::BasicBlock *LoopBody = createBasicBlock("while.body");
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if (EmitBoolCondBranch) {
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llvm::BasicBlock *ExitBlock = LoopExit.getBlock();
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if (ConditionScope.requiresCleanups())
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ExitBlock = createBasicBlock("while.exit");
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Builder.CreateCondBr(BoolCondVal, LoopBody, ExitBlock);
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if (ExitBlock != LoopExit.getBlock()) {
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EmitBlock(ExitBlock);
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EmitBranchThroughCleanup(LoopExit);
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}
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}
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// Emit the loop body. We have to emit this in a cleanup scope
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// because it might be a singleton DeclStmt.
|
|
{
|
|
RunCleanupsScope BodyScope(*this);
|
|
EmitBlock(LoopBody);
|
|
EmitStmt(S.getBody());
|
|
}
|
|
|
|
BreakContinueStack.pop_back();
|
|
|
|
// Immediately force cleanup.
|
|
ConditionScope.ForceCleanup();
|
|
|
|
// Branch to the loop header again.
|
|
EmitBranch(LoopHeader.getBlock());
|
|
|
|
// Emit the exit block.
|
|
EmitBlock(LoopExit.getBlock(), true);
|
|
|
|
// The LoopHeader typically is just a branch if we skipped emitting
|
|
// a branch, try to erase it.
|
|
if (!EmitBoolCondBranch)
|
|
SimplifyForwardingBlocks(LoopHeader.getBlock());
|
|
}
|
|
|
|
void CodeGenFunction::EmitDoStmt(const DoStmt &S) {
|
|
JumpDest LoopExit = getJumpDestInCurrentScope("do.end");
|
|
JumpDest LoopCond = getJumpDestInCurrentScope("do.cond");
|
|
|
|
// Store the blocks to use for break and continue.
|
|
BreakContinueStack.push_back(BreakContinue(LoopExit, LoopCond));
|
|
|
|
// Emit the body of the loop.
|
|
llvm::BasicBlock *LoopBody = createBasicBlock("do.body");
|
|
EmitBlock(LoopBody);
|
|
{
|
|
RunCleanupsScope BodyScope(*this);
|
|
EmitStmt(S.getBody());
|
|
}
|
|
|
|
BreakContinueStack.pop_back();
|
|
|
|
EmitBlock(LoopCond.getBlock());
|
|
|
|
// C99 6.8.5.2: "The evaluation of the controlling expression takes place
|
|
// after each execution of the loop body."
|
|
|
|
// Evaluate the conditional in the while header.
|
|
// C99 6.8.5p2/p4: The first substatement is executed if the expression
|
|
// compares unequal to 0. The condition must be a scalar type.
|
|
llvm::Value *BoolCondVal = EvaluateExprAsBool(S.getCond());
|
|
|
|
// "do {} while (0)" is common in macros, avoid extra blocks. Be sure
|
|
// to correctly handle break/continue though.
|
|
bool EmitBoolCondBranch = true;
|
|
if (llvm::ConstantInt *C = dyn_cast<llvm::ConstantInt>(BoolCondVal))
|
|
if (C->isZero())
|
|
EmitBoolCondBranch = false;
|
|
|
|
// As long as the condition is true, iterate the loop.
|
|
if (EmitBoolCondBranch)
|
|
Builder.CreateCondBr(BoolCondVal, LoopBody, LoopExit.getBlock());
|
|
|
|
// Emit the exit block.
|
|
EmitBlock(LoopExit.getBlock());
|
|
|
|
// The DoCond block typically is just a branch if we skipped
|
|
// emitting a branch, try to erase it.
|
|
if (!EmitBoolCondBranch)
|
|
SimplifyForwardingBlocks(LoopCond.getBlock());
|
|
}
|
|
|
|
void CodeGenFunction::EmitForStmt(const ForStmt &S) {
|
|
JumpDest LoopExit = getJumpDestInCurrentScope("for.end");
|
|
|
|
RunCleanupsScope ForScope(*this);
|
|
|
|
CGDebugInfo *DI = getDebugInfo();
|
|
if (DI)
|
|
DI->EmitLexicalBlockStart(Builder, S.getSourceRange().getBegin());
|
|
|
|
// Evaluate the first part before the loop.
|
|
if (S.getInit())
|
|
EmitStmt(S.getInit());
|
|
|
|
// Start the loop with a block that tests the condition.
|
|
// If there's an increment, the continue scope will be overwritten
|
|
// later.
|
|
JumpDest Continue = getJumpDestInCurrentScope("for.cond");
|
|
llvm::BasicBlock *CondBlock = Continue.getBlock();
|
|
EmitBlock(CondBlock);
|
|
|
|
// Create a cleanup scope for the condition variable cleanups.
|
|
RunCleanupsScope ConditionScope(*this);
|
|
|
|
llvm::Value *BoolCondVal = 0;
|
|
if (S.getCond()) {
|
|
// If the for statement has a condition scope, emit the local variable
|
|
// declaration.
|
|
llvm::BasicBlock *ExitBlock = LoopExit.getBlock();
|
|
if (S.getConditionVariable()) {
|
|
EmitAutoVarDecl(*S.getConditionVariable());
|
|
}
|
|
|
|
// If there are any cleanups between here and the loop-exit scope,
|
|
// create a block to stage a loop exit along.
|
|
if (ForScope.requiresCleanups())
|
|
ExitBlock = createBasicBlock("for.cond.cleanup");
|
|
|
|
// As long as the condition is true, iterate the loop.
|
|
llvm::BasicBlock *ForBody = createBasicBlock("for.body");
|
|
|
|
// C99 6.8.5p2/p4: The first substatement is executed if the expression
|
|
// compares unequal to 0. The condition must be a scalar type.
|
|
BoolCondVal = EvaluateExprAsBool(S.getCond());
|
|
Builder.CreateCondBr(BoolCondVal, ForBody, ExitBlock);
|
|
|
|
if (ExitBlock != LoopExit.getBlock()) {
|
|
EmitBlock(ExitBlock);
|
|
EmitBranchThroughCleanup(LoopExit);
|
|
}
|
|
|
|
EmitBlock(ForBody);
|
|
} else {
|
|
// Treat it as a non-zero constant. Don't even create a new block for the
|
|
// body, just fall into it.
|
|
}
|
|
|
|
// If the for loop doesn't have an increment we can just use the
|
|
// condition as the continue block. Otherwise we'll need to create
|
|
// a block for it (in the current scope, i.e. in the scope of the
|
|
// condition), and that we will become our continue block.
|
|
if (S.getInc())
|
|
Continue = getJumpDestInCurrentScope("for.inc");
|
|
|
|
// Store the blocks to use for break and continue.
|
|
BreakContinueStack.push_back(BreakContinue(LoopExit, Continue));
|
|
|
|
{
|
|
// Create a separate cleanup scope for the body, in case it is not
|
|
// a compound statement.
|
|
RunCleanupsScope BodyScope(*this);
|
|
EmitStmt(S.getBody());
|
|
}
|
|
|
|
// If there is an increment, emit it next.
|
|
if (S.getInc()) {
|
|
EmitBlock(Continue.getBlock());
|
|
EmitStmt(S.getInc());
|
|
}
|
|
|
|
BreakContinueStack.pop_back();
|
|
|
|
ConditionScope.ForceCleanup();
|
|
EmitBranch(CondBlock);
|
|
|
|
ForScope.ForceCleanup();
|
|
|
|
if (DI)
|
|
DI->EmitLexicalBlockEnd(Builder, S.getSourceRange().getEnd());
|
|
|
|
// Emit the fall-through block.
|
|
EmitBlock(LoopExit.getBlock(), true);
|
|
}
|
|
|
|
void CodeGenFunction::EmitCXXForRangeStmt(const CXXForRangeStmt &S) {
|
|
JumpDest LoopExit = getJumpDestInCurrentScope("for.end");
|
|
|
|
RunCleanupsScope ForScope(*this);
|
|
|
|
CGDebugInfo *DI = getDebugInfo();
|
|
if (DI)
|
|
DI->EmitLexicalBlockStart(Builder, S.getSourceRange().getBegin());
|
|
|
|
// Evaluate the first pieces before the loop.
|
|
EmitStmt(S.getRangeStmt());
|
|
EmitStmt(S.getBeginEndStmt());
|
|
|
|
// Start the loop with a block that tests the condition.
|
|
// If there's an increment, the continue scope will be overwritten
|
|
// later.
|
|
llvm::BasicBlock *CondBlock = createBasicBlock("for.cond");
|
|
EmitBlock(CondBlock);
|
|
|
|
// If there are any cleanups between here and the loop-exit scope,
|
|
// create a block to stage a loop exit along.
|
|
llvm::BasicBlock *ExitBlock = LoopExit.getBlock();
|
|
if (ForScope.requiresCleanups())
|
|
ExitBlock = createBasicBlock("for.cond.cleanup");
|
|
|
|
// The loop body, consisting of the specified body and the loop variable.
|
|
llvm::BasicBlock *ForBody = createBasicBlock("for.body");
|
|
|
|
// The body is executed if the expression, contextually converted
|
|
// to bool, is true.
|
|
llvm::Value *BoolCondVal = EvaluateExprAsBool(S.getCond());
|
|
Builder.CreateCondBr(BoolCondVal, ForBody, ExitBlock);
|
|
|
|
if (ExitBlock != LoopExit.getBlock()) {
|
|
EmitBlock(ExitBlock);
|
|
EmitBranchThroughCleanup(LoopExit);
|
|
}
|
|
|
|
EmitBlock(ForBody);
|
|
|
|
// Create a block for the increment. In case of a 'continue', we jump there.
|
|
JumpDest Continue = getJumpDestInCurrentScope("for.inc");
|
|
|
|
// Store the blocks to use for break and continue.
|
|
BreakContinueStack.push_back(BreakContinue(LoopExit, Continue));
|
|
|
|
{
|
|
// Create a separate cleanup scope for the loop variable and body.
|
|
RunCleanupsScope BodyScope(*this);
|
|
EmitStmt(S.getLoopVarStmt());
|
|
EmitStmt(S.getBody());
|
|
}
|
|
|
|
// If there is an increment, emit it next.
|
|
EmitBlock(Continue.getBlock());
|
|
EmitStmt(S.getInc());
|
|
|
|
BreakContinueStack.pop_back();
|
|
|
|
EmitBranch(CondBlock);
|
|
|
|
ForScope.ForceCleanup();
|
|
|
|
if (DI)
|
|
DI->EmitLexicalBlockEnd(Builder, S.getSourceRange().getEnd());
|
|
|
|
// Emit the fall-through block.
|
|
EmitBlock(LoopExit.getBlock(), true);
|
|
}
|
|
|
|
void CodeGenFunction::EmitReturnOfRValue(RValue RV, QualType Ty) {
|
|
if (RV.isScalar()) {
|
|
Builder.CreateStore(RV.getScalarVal(), ReturnValue);
|
|
} else if (RV.isAggregate()) {
|
|
EmitAggregateCopy(ReturnValue, RV.getAggregateAddr(), Ty);
|
|
} else {
|
|
StoreComplexToAddr(RV.getComplexVal(), ReturnValue, false);
|
|
}
|
|
EmitBranchThroughCleanup(ReturnBlock);
|
|
}
|
|
|
|
/// EmitReturnStmt - Note that due to GCC extensions, this can have an operand
|
|
/// if the function returns void, or may be missing one if the function returns
|
|
/// non-void. Fun stuff :).
|
|
void CodeGenFunction::EmitReturnStmt(const ReturnStmt &S) {
|
|
// Emit the result value, even if unused, to evalute the side effects.
|
|
const Expr *RV = S.getRetValue();
|
|
|
|
// FIXME: Clean this up by using an LValue for ReturnTemp,
|
|
// EmitStoreThroughLValue, and EmitAnyExpr.
|
|
if (S.getNRVOCandidate() && S.getNRVOCandidate()->isNRVOVariable() &&
|
|
!Target.useGlobalsForAutomaticVariables()) {
|
|
// Apply the named return value optimization for this return statement,
|
|
// which means doing nothing: the appropriate result has already been
|
|
// constructed into the NRVO variable.
|
|
|
|
// If there is an NRVO flag for this variable, set it to 1 into indicate
|
|
// that the cleanup code should not destroy the variable.
|
|
if (llvm::Value *NRVOFlag = NRVOFlags[S.getNRVOCandidate()])
|
|
Builder.CreateStore(Builder.getTrue(), NRVOFlag);
|
|
} else if (!ReturnValue) {
|
|
// Make sure not to return anything, but evaluate the expression
|
|
// for side effects.
|
|
if (RV)
|
|
EmitAnyExpr(RV);
|
|
} else if (RV == 0) {
|
|
// Do nothing (return value is left uninitialized)
|
|
} else if (FnRetTy->isReferenceType()) {
|
|
// If this function returns a reference, take the address of the expression
|
|
// rather than the value.
|
|
RValue Result = EmitReferenceBindingToExpr(RV, /*InitializedDecl=*/0);
|
|
Builder.CreateStore(Result.getScalarVal(), ReturnValue);
|
|
} else if (!hasAggregateLLVMType(RV->getType())) {
|
|
Builder.CreateStore(EmitScalarExpr(RV), ReturnValue);
|
|
} else if (RV->getType()->isAnyComplexType()) {
|
|
EmitComplexExprIntoAddr(RV, ReturnValue, false);
|
|
} else {
|
|
CharUnits Alignment = getContext().getTypeAlignInChars(RV->getType());
|
|
EmitAggExpr(RV, AggValueSlot::forAddr(ReturnValue, Alignment, Qualifiers(),
|
|
AggValueSlot::IsDestructed,
|
|
AggValueSlot::DoesNotNeedGCBarriers,
|
|
AggValueSlot::IsNotAliased));
|
|
}
|
|
|
|
EmitBranchThroughCleanup(ReturnBlock);
|
|
}
|
|
|
|
void CodeGenFunction::EmitDeclStmt(const DeclStmt &S) {
|
|
// As long as debug info is modeled with instructions, we have to ensure we
|
|
// have a place to insert here and write the stop point here.
|
|
if (HaveInsertPoint())
|
|
EmitStopPoint(&S);
|
|
|
|
for (DeclStmt::const_decl_iterator I = S.decl_begin(), E = S.decl_end();
|
|
I != E; ++I)
|
|
EmitDecl(**I);
|
|
}
|
|
|
|
void CodeGenFunction::EmitBreakStmt(const BreakStmt &S) {
|
|
assert(!BreakContinueStack.empty() && "break stmt not in a loop or switch!");
|
|
|
|
// If this code is reachable then emit a stop point (if generating
|
|
// debug info). We have to do this ourselves because we are on the
|
|
// "simple" statement path.
|
|
if (HaveInsertPoint())
|
|
EmitStopPoint(&S);
|
|
|
|
JumpDest Block = BreakContinueStack.back().BreakBlock;
|
|
EmitBranchThroughCleanup(Block);
|
|
}
|
|
|
|
void CodeGenFunction::EmitContinueStmt(const ContinueStmt &S) {
|
|
assert(!BreakContinueStack.empty() && "continue stmt not in a loop!");
|
|
|
|
// If this code is reachable then emit a stop point (if generating
|
|
// debug info). We have to do this ourselves because we are on the
|
|
// "simple" statement path.
|
|
if (HaveInsertPoint())
|
|
EmitStopPoint(&S);
|
|
|
|
JumpDest Block = BreakContinueStack.back().ContinueBlock;
|
|
EmitBranchThroughCleanup(Block);
|
|
}
|
|
|
|
/// EmitCaseStmtRange - If case statement range is not too big then
|
|
/// add multiple cases to switch instruction, one for each value within
|
|
/// the range. If range is too big then emit "if" condition check.
|
|
void CodeGenFunction::EmitCaseStmtRange(const CaseStmt &S) {
|
|
assert(S.getRHS() && "Expected RHS value in CaseStmt");
|
|
|
|
llvm::APSInt LHS = S.getLHS()->EvaluateKnownConstInt(getContext());
|
|
llvm::APSInt RHS = S.getRHS()->EvaluateKnownConstInt(getContext());
|
|
|
|
// Emit the code for this case. We do this first to make sure it is
|
|
// properly chained from our predecessor before generating the
|
|
// switch machinery to enter this block.
|
|
EmitBlock(createBasicBlock("sw.bb"));
|
|
llvm::BasicBlock *CaseDest = Builder.GetInsertBlock();
|
|
EmitStmt(S.getSubStmt());
|
|
|
|
// If range is empty, do nothing.
|
|
if (LHS.isSigned() ? RHS.slt(LHS) : RHS.ult(LHS))
|
|
return;
|
|
|
|
llvm::APInt Range = RHS - LHS;
|
|
// FIXME: parameters such as this should not be hardcoded.
|
|
if (Range.ult(llvm::APInt(Range.getBitWidth(), 64))) {
|
|
// Range is small enough to add multiple switch instruction cases.
|
|
for (unsigned i = 0, e = Range.getZExtValue() + 1; i != e; ++i) {
|
|
SwitchInsn->addCase(Builder.getInt(LHS), CaseDest);
|
|
LHS++;
|
|
}
|
|
return;
|
|
}
|
|
|
|
// The range is too big. Emit "if" condition into a new block,
|
|
// making sure to save and restore the current insertion point.
|
|
llvm::BasicBlock *RestoreBB = Builder.GetInsertBlock();
|
|
|
|
// Push this test onto the chain of range checks (which terminates
|
|
// in the default basic block). The switch's default will be changed
|
|
// to the top of this chain after switch emission is complete.
|
|
llvm::BasicBlock *FalseDest = CaseRangeBlock;
|
|
CaseRangeBlock = createBasicBlock("sw.caserange");
|
|
|
|
CurFn->getBasicBlockList().push_back(CaseRangeBlock);
|
|
Builder.SetInsertPoint(CaseRangeBlock);
|
|
|
|
// Emit range check.
|
|
llvm::Value *Diff =
|
|
Builder.CreateSub(SwitchInsn->getCondition(), Builder.getInt(LHS));
|
|
llvm::Value *Cond =
|
|
Builder.CreateICmpULE(Diff, Builder.getInt(Range), "inbounds");
|
|
Builder.CreateCondBr(Cond, CaseDest, FalseDest);
|
|
|
|
// Restore the appropriate insertion point.
|
|
if (RestoreBB)
|
|
Builder.SetInsertPoint(RestoreBB);
|
|
else
|
|
Builder.ClearInsertionPoint();
|
|
}
|
|
|
|
void CodeGenFunction::EmitCaseStmt(const CaseStmt &S) {
|
|
// If there is no enclosing switch instance that we're aware of, then this
|
|
// case statement and its block can be elided. This situation only happens
|
|
// when we've constant-folded the switch, are emitting the constant case,
|
|
// and part of the constant case includes another case statement. For
|
|
// instance: switch (4) { case 4: do { case 5: } while (1); }
|
|
if (!SwitchInsn) {
|
|
EmitStmt(S.getSubStmt());
|
|
return;
|
|
}
|
|
|
|
// Handle case ranges.
|
|
if (S.getRHS()) {
|
|
EmitCaseStmtRange(S);
|
|
return;
|
|
}
|
|
|
|
llvm::ConstantInt *CaseVal =
|
|
Builder.getInt(S.getLHS()->EvaluateKnownConstInt(getContext()));
|
|
|
|
// If the body of the case is just a 'break', and if there was no fallthrough,
|
|
// try to not emit an empty block.
|
|
if ((CGM.getCodeGenOpts().OptimizationLevel > 0) && isa<BreakStmt>(S.getSubStmt())) {
|
|
JumpDest Block = BreakContinueStack.back().BreakBlock;
|
|
|
|
// Only do this optimization if there are no cleanups that need emitting.
|
|
if (isObviouslyBranchWithoutCleanups(Block)) {
|
|
SwitchInsn->addCase(CaseVal, Block.getBlock());
|
|
|
|
// If there was a fallthrough into this case, make sure to redirect it to
|
|
// the end of the switch as well.
|
|
if (Builder.GetInsertBlock()) {
|
|
Builder.CreateBr(Block.getBlock());
|
|
Builder.ClearInsertionPoint();
|
|
}
|
|
return;
|
|
}
|
|
}
|
|
|
|
EmitBlock(createBasicBlock("sw.bb"));
|
|
llvm::BasicBlock *CaseDest = Builder.GetInsertBlock();
|
|
SwitchInsn->addCase(CaseVal, CaseDest);
|
|
|
|
// Recursively emitting the statement is acceptable, but is not wonderful for
|
|
// code where we have many case statements nested together, i.e.:
|
|
// case 1:
|
|
// case 2:
|
|
// case 3: etc.
|
|
// Handling this recursively will create a new block for each case statement
|
|
// that falls through to the next case which is IR intensive. It also causes
|
|
// deep recursion which can run into stack depth limitations. Handle
|
|
// sequential non-range case statements specially.
|
|
const CaseStmt *CurCase = &S;
|
|
const CaseStmt *NextCase = dyn_cast<CaseStmt>(S.getSubStmt());
|
|
|
|
// Otherwise, iteratively add consecutive cases to this switch stmt.
|
|
while (NextCase && NextCase->getRHS() == 0) {
|
|
CurCase = NextCase;
|
|
llvm::ConstantInt *CaseVal =
|
|
Builder.getInt(CurCase->getLHS()->EvaluateKnownConstInt(getContext()));
|
|
SwitchInsn->addCase(CaseVal, CaseDest);
|
|
NextCase = dyn_cast<CaseStmt>(CurCase->getSubStmt());
|
|
}
|
|
|
|
// Normal default recursion for non-cases.
|
|
EmitStmt(CurCase->getSubStmt());
|
|
}
|
|
|
|
void CodeGenFunction::EmitDefaultStmt(const DefaultStmt &S) {
|
|
llvm::BasicBlock *DefaultBlock = SwitchInsn->getDefaultDest();
|
|
assert(DefaultBlock->empty() &&
|
|
"EmitDefaultStmt: Default block already defined?");
|
|
EmitBlock(DefaultBlock);
|
|
EmitStmt(S.getSubStmt());
|
|
}
|
|
|
|
/// CollectStatementsForCase - Given the body of a 'switch' statement and a
|
|
/// constant value that is being switched on, see if we can dead code eliminate
|
|
/// the body of the switch to a simple series of statements to emit. Basically,
|
|
/// on a switch (5) we want to find these statements:
|
|
/// case 5:
|
|
/// printf(...); <--
|
|
/// ++i; <--
|
|
/// break;
|
|
///
|
|
/// and add them to the ResultStmts vector. If it is unsafe to do this
|
|
/// transformation (for example, one of the elided statements contains a label
|
|
/// that might be jumped to), return CSFC_Failure. If we handled it and 'S'
|
|
/// should include statements after it (e.g. the printf() line is a substmt of
|
|
/// the case) then return CSFC_FallThrough. If we handled it and found a break
|
|
/// statement, then return CSFC_Success.
|
|
///
|
|
/// If Case is non-null, then we are looking for the specified case, checking
|
|
/// that nothing we jump over contains labels. If Case is null, then we found
|
|
/// the case and are looking for the break.
|
|
///
|
|
/// If the recursive walk actually finds our Case, then we set FoundCase to
|
|
/// true.
|
|
///
|
|
enum CSFC_Result { CSFC_Failure, CSFC_FallThrough, CSFC_Success };
|
|
static CSFC_Result CollectStatementsForCase(const Stmt *S,
|
|
const SwitchCase *Case,
|
|
bool &FoundCase,
|
|
SmallVectorImpl<const Stmt*> &ResultStmts) {
|
|
// If this is a null statement, just succeed.
|
|
if (S == 0)
|
|
return Case ? CSFC_Success : CSFC_FallThrough;
|
|
|
|
// If this is the switchcase (case 4: or default) that we're looking for, then
|
|
// we're in business. Just add the substatement.
|
|
if (const SwitchCase *SC = dyn_cast<SwitchCase>(S)) {
|
|
if (S == Case) {
|
|
FoundCase = true;
|
|
return CollectStatementsForCase(SC->getSubStmt(), 0, FoundCase,
|
|
ResultStmts);
|
|
}
|
|
|
|
// Otherwise, this is some other case or default statement, just ignore it.
|
|
return CollectStatementsForCase(SC->getSubStmt(), Case, FoundCase,
|
|
ResultStmts);
|
|
}
|
|
|
|
// If we are in the live part of the code and we found our break statement,
|
|
// return a success!
|
|
if (Case == 0 && isa<BreakStmt>(S))
|
|
return CSFC_Success;
|
|
|
|
// If this is a switch statement, then it might contain the SwitchCase, the
|
|
// break, or neither.
|
|
if (const CompoundStmt *CS = dyn_cast<CompoundStmt>(S)) {
|
|
// Handle this as two cases: we might be looking for the SwitchCase (if so
|
|
// the skipped statements must be skippable) or we might already have it.
|
|
CompoundStmt::const_body_iterator I = CS->body_begin(), E = CS->body_end();
|
|
if (Case) {
|
|
// Keep track of whether we see a skipped declaration. The code could be
|
|
// using the declaration even if it is skipped, so we can't optimize out
|
|
// the decl if the kept statements might refer to it.
|
|
bool HadSkippedDecl = false;
|
|
|
|
// If we're looking for the case, just see if we can skip each of the
|
|
// substatements.
|
|
for (; Case && I != E; ++I) {
|
|
HadSkippedDecl |= isa<DeclStmt>(*I);
|
|
|
|
switch (CollectStatementsForCase(*I, Case, FoundCase, ResultStmts)) {
|
|
case CSFC_Failure: return CSFC_Failure;
|
|
case CSFC_Success:
|
|
// A successful result means that either 1) that the statement doesn't
|
|
// have the case and is skippable, or 2) does contain the case value
|
|
// and also contains the break to exit the switch. In the later case,
|
|
// we just verify the rest of the statements are elidable.
|
|
if (FoundCase) {
|
|
// If we found the case and skipped declarations, we can't do the
|
|
// optimization.
|
|
if (HadSkippedDecl)
|
|
return CSFC_Failure;
|
|
|
|
for (++I; I != E; ++I)
|
|
if (CodeGenFunction::ContainsLabel(*I, true))
|
|
return CSFC_Failure;
|
|
return CSFC_Success;
|
|
}
|
|
break;
|
|
case CSFC_FallThrough:
|
|
// If we have a fallthrough condition, then we must have found the
|
|
// case started to include statements. Consider the rest of the
|
|
// statements in the compound statement as candidates for inclusion.
|
|
assert(FoundCase && "Didn't find case but returned fallthrough?");
|
|
// We recursively found Case, so we're not looking for it anymore.
|
|
Case = 0;
|
|
|
|
// If we found the case and skipped declarations, we can't do the
|
|
// optimization.
|
|
if (HadSkippedDecl)
|
|
return CSFC_Failure;
|
|
break;
|
|
}
|
|
}
|
|
}
|
|
|
|
// If we have statements in our range, then we know that the statements are
|
|
// live and need to be added to the set of statements we're tracking.
|
|
for (; I != E; ++I) {
|
|
switch (CollectStatementsForCase(*I, 0, FoundCase, ResultStmts)) {
|
|
case CSFC_Failure: return CSFC_Failure;
|
|
case CSFC_FallThrough:
|
|
// A fallthrough result means that the statement was simple and just
|
|
// included in ResultStmt, keep adding them afterwards.
|
|
break;
|
|
case CSFC_Success:
|
|
// A successful result means that we found the break statement and
|
|
// stopped statement inclusion. We just ensure that any leftover stmts
|
|
// are skippable and return success ourselves.
|
|
for (++I; I != E; ++I)
|
|
if (CodeGenFunction::ContainsLabel(*I, true))
|
|
return CSFC_Failure;
|
|
return CSFC_Success;
|
|
}
|
|
}
|
|
|
|
return Case ? CSFC_Success : CSFC_FallThrough;
|
|
}
|
|
|
|
// Okay, this is some other statement that we don't handle explicitly, like a
|
|
// for statement or increment etc. If we are skipping over this statement,
|
|
// just verify it doesn't have labels, which would make it invalid to elide.
|
|
if (Case) {
|
|
if (CodeGenFunction::ContainsLabel(S, true))
|
|
return CSFC_Failure;
|
|
return CSFC_Success;
|
|
}
|
|
|
|
// Otherwise, we want to include this statement. Everything is cool with that
|
|
// so long as it doesn't contain a break out of the switch we're in.
|
|
if (CodeGenFunction::containsBreak(S)) return CSFC_Failure;
|
|
|
|
// Otherwise, everything is great. Include the statement and tell the caller
|
|
// that we fall through and include the next statement as well.
|
|
ResultStmts.push_back(S);
|
|
return CSFC_FallThrough;
|
|
}
|
|
|
|
/// FindCaseStatementsForValue - Find the case statement being jumped to and
|
|
/// then invoke CollectStatementsForCase to find the list of statements to emit
|
|
/// for a switch on constant. See the comment above CollectStatementsForCase
|
|
/// for more details.
|
|
static bool FindCaseStatementsForValue(const SwitchStmt &S,
|
|
const llvm::APInt &ConstantCondValue,
|
|
SmallVectorImpl<const Stmt*> &ResultStmts,
|
|
ASTContext &C) {
|
|
// First step, find the switch case that is being branched to. We can do this
|
|
// efficiently by scanning the SwitchCase list.
|
|
const SwitchCase *Case = S.getSwitchCaseList();
|
|
const DefaultStmt *DefaultCase = 0;
|
|
|
|
for (; Case; Case = Case->getNextSwitchCase()) {
|
|
// It's either a default or case. Just remember the default statement in
|
|
// case we're not jumping to any numbered cases.
|
|
if (const DefaultStmt *DS = dyn_cast<DefaultStmt>(Case)) {
|
|
DefaultCase = DS;
|
|
continue;
|
|
}
|
|
|
|
// Check to see if this case is the one we're looking for.
|
|
const CaseStmt *CS = cast<CaseStmt>(Case);
|
|
// Don't handle case ranges yet.
|
|
if (CS->getRHS()) return false;
|
|
|
|
// If we found our case, remember it as 'case'.
|
|
if (CS->getLHS()->EvaluateKnownConstInt(C) == ConstantCondValue)
|
|
break;
|
|
}
|
|
|
|
// If we didn't find a matching case, we use a default if it exists, or we
|
|
// elide the whole switch body!
|
|
if (Case == 0) {
|
|
// It is safe to elide the body of the switch if it doesn't contain labels
|
|
// etc. If it is safe, return successfully with an empty ResultStmts list.
|
|
if (DefaultCase == 0)
|
|
return !CodeGenFunction::ContainsLabel(&S);
|
|
Case = DefaultCase;
|
|
}
|
|
|
|
// Ok, we know which case is being jumped to, try to collect all the
|
|
// statements that follow it. This can fail for a variety of reasons. Also,
|
|
// check to see that the recursive walk actually found our case statement.
|
|
// Insane cases like this can fail to find it in the recursive walk since we
|
|
// don't handle every stmt kind:
|
|
// switch (4) {
|
|
// while (1) {
|
|
// case 4: ...
|
|
bool FoundCase = false;
|
|
return CollectStatementsForCase(S.getBody(), Case, FoundCase,
|
|
ResultStmts) != CSFC_Failure &&
|
|
FoundCase;
|
|
}
|
|
|
|
void CodeGenFunction::EmitSwitchStmt(const SwitchStmt &S) {
|
|
JumpDest SwitchExit = getJumpDestInCurrentScope("sw.epilog");
|
|
|
|
RunCleanupsScope ConditionScope(*this);
|
|
|
|
if (S.getConditionVariable())
|
|
EmitAutoVarDecl(*S.getConditionVariable());
|
|
|
|
// Handle nested switch statements.
|
|
llvm::SwitchInst *SavedSwitchInsn = SwitchInsn;
|
|
llvm::BasicBlock *SavedCRBlock = CaseRangeBlock;
|
|
|
|
// See if we can constant fold the condition of the switch and therefore only
|
|
// emit the live case statement (if any) of the switch.
|
|
llvm::APInt ConstantCondValue;
|
|
if (ConstantFoldsToSimpleInteger(S.getCond(), ConstantCondValue)) {
|
|
SmallVector<const Stmt*, 4> CaseStmts;
|
|
if (FindCaseStatementsForValue(S, ConstantCondValue, CaseStmts,
|
|
getContext())) {
|
|
RunCleanupsScope ExecutedScope(*this);
|
|
|
|
// At this point, we are no longer "within" a switch instance, so
|
|
// we can temporarily enforce this to ensure that any embedded case
|
|
// statements are not emitted.
|
|
SwitchInsn = 0;
|
|
|
|
// Okay, we can dead code eliminate everything except this case. Emit the
|
|
// specified series of statements and we're good.
|
|
for (unsigned i = 0, e = CaseStmts.size(); i != e; ++i)
|
|
EmitStmt(CaseStmts[i]);
|
|
|
|
// Now we want to restore the saved switch instance so that nested
|
|
// switches continue to function properly
|
|
SwitchInsn = SavedSwitchInsn;
|
|
|
|
return;
|
|
}
|
|
}
|
|
|
|
llvm::Value *CondV = EmitScalarExpr(S.getCond());
|
|
|
|
// Create basic block to hold stuff that comes after switch
|
|
// statement. We also need to create a default block now so that
|
|
// explicit case ranges tests can have a place to jump to on
|
|
// failure.
|
|
llvm::BasicBlock *DefaultBlock = createBasicBlock("sw.default");
|
|
SwitchInsn = Builder.CreateSwitch(CondV, DefaultBlock);
|
|
CaseRangeBlock = DefaultBlock;
|
|
|
|
// Clear the insertion point to indicate we are in unreachable code.
|
|
Builder.ClearInsertionPoint();
|
|
|
|
// All break statements jump to NextBlock. If BreakContinueStack is non empty
|
|
// then reuse last ContinueBlock.
|
|
JumpDest OuterContinue;
|
|
if (!BreakContinueStack.empty())
|
|
OuterContinue = BreakContinueStack.back().ContinueBlock;
|
|
|
|
BreakContinueStack.push_back(BreakContinue(SwitchExit, OuterContinue));
|
|
|
|
// Emit switch body.
|
|
EmitStmt(S.getBody());
|
|
|
|
BreakContinueStack.pop_back();
|
|
|
|
// Update the default block in case explicit case range tests have
|
|
// been chained on top.
|
|
SwitchInsn->setDefaultDest(CaseRangeBlock);
|
|
|
|
// If a default was never emitted:
|
|
if (!DefaultBlock->getParent()) {
|
|
// If we have cleanups, emit the default block so that there's a
|
|
// place to jump through the cleanups from.
|
|
if (ConditionScope.requiresCleanups()) {
|
|
EmitBlock(DefaultBlock);
|
|
|
|
// Otherwise, just forward the default block to the switch end.
|
|
} else {
|
|
DefaultBlock->replaceAllUsesWith(SwitchExit.getBlock());
|
|
delete DefaultBlock;
|
|
}
|
|
}
|
|
|
|
ConditionScope.ForceCleanup();
|
|
|
|
// Emit continuation.
|
|
EmitBlock(SwitchExit.getBlock(), true);
|
|
|
|
SwitchInsn = SavedSwitchInsn;
|
|
CaseRangeBlock = SavedCRBlock;
|
|
}
|
|
|
|
static std::string
|
|
SimplifyConstraint(const char *Constraint, const TargetInfo &Target,
|
|
SmallVectorImpl<TargetInfo::ConstraintInfo> *OutCons=0) {
|
|
std::string Result;
|
|
|
|
while (*Constraint) {
|
|
switch (*Constraint) {
|
|
default:
|
|
Result += Target.convertConstraint(Constraint);
|
|
break;
|
|
// Ignore these
|
|
case '*':
|
|
case '?':
|
|
case '!':
|
|
case '=': // Will see this and the following in mult-alt constraints.
|
|
case '+':
|
|
break;
|
|
case ',':
|
|
Result += "|";
|
|
break;
|
|
case 'g':
|
|
Result += "imr";
|
|
break;
|
|
case '[': {
|
|
assert(OutCons &&
|
|
"Must pass output names to constraints with a symbolic name");
|
|
unsigned Index;
|
|
bool result = Target.resolveSymbolicName(Constraint,
|
|
&(*OutCons)[0],
|
|
OutCons->size(), Index);
|
|
assert(result && "Could not resolve symbolic name"); (void)result;
|
|
Result += llvm::utostr(Index);
|
|
break;
|
|
}
|
|
}
|
|
|
|
Constraint++;
|
|
}
|
|
|
|
return Result;
|
|
}
|
|
|
|
/// AddVariableConstraints - Look at AsmExpr and if it is a variable declared
|
|
/// as using a particular register add that as a constraint that will be used
|
|
/// in this asm stmt.
|
|
static std::string
|
|
AddVariableConstraints(const std::string &Constraint, const Expr &AsmExpr,
|
|
const TargetInfo &Target, CodeGenModule &CGM,
|
|
const AsmStmt &Stmt) {
|
|
const DeclRefExpr *AsmDeclRef = dyn_cast<DeclRefExpr>(&AsmExpr);
|
|
if (!AsmDeclRef)
|
|
return Constraint;
|
|
const ValueDecl &Value = *AsmDeclRef->getDecl();
|
|
const VarDecl *Variable = dyn_cast<VarDecl>(&Value);
|
|
if (!Variable)
|
|
return Constraint;
|
|
if (Variable->getStorageClass() != SC_Register)
|
|
return Constraint;
|
|
AsmLabelAttr *Attr = Variable->getAttr<AsmLabelAttr>();
|
|
if (!Attr)
|
|
return Constraint;
|
|
StringRef Register = Attr->getLabel();
|
|
assert(Target.isValidGCCRegisterName(Register));
|
|
// We're using validateOutputConstraint here because we only care if
|
|
// this is a register constraint.
|
|
TargetInfo::ConstraintInfo Info(Constraint, "");
|
|
if (Target.validateOutputConstraint(Info) &&
|
|
!Info.allowsRegister()) {
|
|
CGM.ErrorUnsupported(&Stmt, "__asm__");
|
|
return Constraint;
|
|
}
|
|
// Canonicalize the register here before returning it.
|
|
Register = Target.getNormalizedGCCRegisterName(Register);
|
|
return "{" + Register.str() + "}";
|
|
}
|
|
|
|
llvm::Value*
|
|
CodeGenFunction::EmitAsmInputLValue(const AsmStmt &S,
|
|
const TargetInfo::ConstraintInfo &Info,
|
|
LValue InputValue, QualType InputType,
|
|
std::string &ConstraintStr) {
|
|
llvm::Value *Arg;
|
|
if (Info.allowsRegister() || !Info.allowsMemory()) {
|
|
if (!CodeGenFunction::hasAggregateLLVMType(InputType)) {
|
|
Arg = EmitLoadOfLValue(InputValue).getScalarVal();
|
|
} else {
|
|
llvm::Type *Ty = ConvertType(InputType);
|
|
uint64_t Size = CGM.getTargetData().getTypeSizeInBits(Ty);
|
|
if (Size <= 64 && llvm::isPowerOf2_64(Size)) {
|
|
Ty = llvm::IntegerType::get(getLLVMContext(), Size);
|
|
Ty = llvm::PointerType::getUnqual(Ty);
|
|
|
|
Arg = Builder.CreateLoad(Builder.CreateBitCast(InputValue.getAddress(),
|
|
Ty));
|
|
} else {
|
|
Arg = InputValue.getAddress();
|
|
ConstraintStr += '*';
|
|
}
|
|
}
|
|
} else {
|
|
Arg = InputValue.getAddress();
|
|
ConstraintStr += '*';
|
|
}
|
|
|
|
return Arg;
|
|
}
|
|
|
|
llvm::Value* CodeGenFunction::EmitAsmInput(const AsmStmt &S,
|
|
const TargetInfo::ConstraintInfo &Info,
|
|
const Expr *InputExpr,
|
|
std::string &ConstraintStr) {
|
|
if (Info.allowsRegister() || !Info.allowsMemory())
|
|
if (!CodeGenFunction::hasAggregateLLVMType(InputExpr->getType()))
|
|
return EmitScalarExpr(InputExpr);
|
|
|
|
InputExpr = InputExpr->IgnoreParenNoopCasts(getContext());
|
|
LValue Dest = EmitLValue(InputExpr);
|
|
return EmitAsmInputLValue(S, Info, Dest, InputExpr->getType(), ConstraintStr);
|
|
}
|
|
|
|
/// getAsmSrcLocInfo - Return the !srcloc metadata node to attach to an inline
|
|
/// asm call instruction. The !srcloc MDNode contains a list of constant
|
|
/// integers which are the source locations of the start of each line in the
|
|
/// asm.
|
|
static llvm::MDNode *getAsmSrcLocInfo(const StringLiteral *Str,
|
|
CodeGenFunction &CGF) {
|
|
SmallVector<llvm::Value *, 8> Locs;
|
|
// Add the location of the first line to the MDNode.
|
|
Locs.push_back(llvm::ConstantInt::get(CGF.Int32Ty,
|
|
Str->getLocStart().getRawEncoding()));
|
|
StringRef StrVal = Str->getString();
|
|
if (!StrVal.empty()) {
|
|
const SourceManager &SM = CGF.CGM.getContext().getSourceManager();
|
|
const LangOptions &LangOpts = CGF.CGM.getLangOpts();
|
|
|
|
// Add the location of the start of each subsequent line of the asm to the
|
|
// MDNode.
|
|
for (unsigned i = 0, e = StrVal.size()-1; i != e; ++i) {
|
|
if (StrVal[i] != '\n') continue;
|
|
SourceLocation LineLoc = Str->getLocationOfByte(i+1, SM, LangOpts,
|
|
CGF.Target);
|
|
Locs.push_back(llvm::ConstantInt::get(CGF.Int32Ty,
|
|
LineLoc.getRawEncoding()));
|
|
}
|
|
}
|
|
|
|
return llvm::MDNode::get(CGF.getLLVMContext(), Locs);
|
|
}
|
|
|
|
void CodeGenFunction::EmitAsmStmt(const AsmStmt &S) {
|
|
// Analyze the asm string to decompose it into its pieces. We know that Sema
|
|
// has already done this, so it is guaranteed to be successful.
|
|
SmallVector<AsmStmt::AsmStringPiece, 4> Pieces;
|
|
unsigned DiagOffs;
|
|
S.AnalyzeAsmString(Pieces, getContext(), DiagOffs);
|
|
|
|
// Assemble the pieces into the final asm string.
|
|
std::string AsmString;
|
|
for (unsigned i = 0, e = Pieces.size(); i != e; ++i) {
|
|
if (Pieces[i].isString())
|
|
AsmString += Pieces[i].getString();
|
|
else if (Pieces[i].getModifier() == '\0')
|
|
AsmString += '$' + llvm::utostr(Pieces[i].getOperandNo());
|
|
else
|
|
AsmString += "${" + llvm::utostr(Pieces[i].getOperandNo()) + ':' +
|
|
Pieces[i].getModifier() + '}';
|
|
}
|
|
|
|
// Get all the output and input constraints together.
|
|
SmallVector<TargetInfo::ConstraintInfo, 4> OutputConstraintInfos;
|
|
SmallVector<TargetInfo::ConstraintInfo, 4> InputConstraintInfos;
|
|
|
|
for (unsigned i = 0, e = S.getNumOutputs(); i != e; i++) {
|
|
TargetInfo::ConstraintInfo Info(S.getOutputConstraint(i),
|
|
S.getOutputName(i));
|
|
bool IsValid = Target.validateOutputConstraint(Info); (void)IsValid;
|
|
assert(IsValid && "Failed to parse output constraint");
|
|
OutputConstraintInfos.push_back(Info);
|
|
}
|
|
|
|
for (unsigned i = 0, e = S.getNumInputs(); i != e; i++) {
|
|
TargetInfo::ConstraintInfo Info(S.getInputConstraint(i),
|
|
S.getInputName(i));
|
|
bool IsValid = Target.validateInputConstraint(OutputConstraintInfos.data(),
|
|
S.getNumOutputs(), Info);
|
|
assert(IsValid && "Failed to parse input constraint"); (void)IsValid;
|
|
InputConstraintInfos.push_back(Info);
|
|
}
|
|
|
|
std::string Constraints;
|
|
|
|
std::vector<LValue> ResultRegDests;
|
|
std::vector<QualType> ResultRegQualTys;
|
|
std::vector<llvm::Type *> ResultRegTypes;
|
|
std::vector<llvm::Type *> ResultTruncRegTypes;
|
|
std::vector<llvm::Type*> ArgTypes;
|
|
std::vector<llvm::Value*> Args;
|
|
|
|
// Keep track of inout constraints.
|
|
std::string InOutConstraints;
|
|
std::vector<llvm::Value*> InOutArgs;
|
|
std::vector<llvm::Type*> InOutArgTypes;
|
|
|
|
for (unsigned i = 0, e = S.getNumOutputs(); i != e; i++) {
|
|
TargetInfo::ConstraintInfo &Info = OutputConstraintInfos[i];
|
|
|
|
// Simplify the output constraint.
|
|
std::string OutputConstraint(S.getOutputConstraint(i));
|
|
OutputConstraint = SimplifyConstraint(OutputConstraint.c_str() + 1, Target);
|
|
|
|
const Expr *OutExpr = S.getOutputExpr(i);
|
|
OutExpr = OutExpr->IgnoreParenNoopCasts(getContext());
|
|
|
|
OutputConstraint = AddVariableConstraints(OutputConstraint, *OutExpr,
|
|
Target, CGM, S);
|
|
|
|
LValue Dest = EmitLValue(OutExpr);
|
|
if (!Constraints.empty())
|
|
Constraints += ',';
|
|
|
|
// If this is a register output, then make the inline asm return it
|
|
// by-value. If this is a memory result, return the value by-reference.
|
|
if (!Info.allowsMemory() && !hasAggregateLLVMType(OutExpr->getType())) {
|
|
Constraints += "=" + OutputConstraint;
|
|
ResultRegQualTys.push_back(OutExpr->getType());
|
|
ResultRegDests.push_back(Dest);
|
|
ResultRegTypes.push_back(ConvertTypeForMem(OutExpr->getType()));
|
|
ResultTruncRegTypes.push_back(ResultRegTypes.back());
|
|
|
|
// If this output is tied to an input, and if the input is larger, then
|
|
// we need to set the actual result type of the inline asm node to be the
|
|
// same as the input type.
|
|
if (Info.hasMatchingInput()) {
|
|
unsigned InputNo;
|
|
for (InputNo = 0; InputNo != S.getNumInputs(); ++InputNo) {
|
|
TargetInfo::ConstraintInfo &Input = InputConstraintInfos[InputNo];
|
|
if (Input.hasTiedOperand() && Input.getTiedOperand() == i)
|
|
break;
|
|
}
|
|
assert(InputNo != S.getNumInputs() && "Didn't find matching input!");
|
|
|
|
QualType InputTy = S.getInputExpr(InputNo)->getType();
|
|
QualType OutputType = OutExpr->getType();
|
|
|
|
uint64_t InputSize = getContext().getTypeSize(InputTy);
|
|
if (getContext().getTypeSize(OutputType) < InputSize) {
|
|
// Form the asm to return the value as a larger integer or fp type.
|
|
ResultRegTypes.back() = ConvertType(InputTy);
|
|
}
|
|
}
|
|
if (llvm::Type* AdjTy =
|
|
getTargetHooks().adjustInlineAsmType(*this, OutputConstraint,
|
|
ResultRegTypes.back()))
|
|
ResultRegTypes.back() = AdjTy;
|
|
} else {
|
|
ArgTypes.push_back(Dest.getAddress()->getType());
|
|
Args.push_back(Dest.getAddress());
|
|
Constraints += "=*";
|
|
Constraints += OutputConstraint;
|
|
}
|
|
|
|
if (Info.isReadWrite()) {
|
|
InOutConstraints += ',';
|
|
|
|
const Expr *InputExpr = S.getOutputExpr(i);
|
|
llvm::Value *Arg = EmitAsmInputLValue(S, Info, Dest, InputExpr->getType(),
|
|
InOutConstraints);
|
|
|
|
if (llvm::Type* AdjTy =
|
|
getTargetHooks().adjustInlineAsmType(*this, OutputConstraint,
|
|
Arg->getType()))
|
|
Arg = Builder.CreateBitCast(Arg, AdjTy);
|
|
|
|
if (Info.allowsRegister())
|
|
InOutConstraints += llvm::utostr(i);
|
|
else
|
|
InOutConstraints += OutputConstraint;
|
|
|
|
InOutArgTypes.push_back(Arg->getType());
|
|
InOutArgs.push_back(Arg);
|
|
}
|
|
}
|
|
|
|
unsigned NumConstraints = S.getNumOutputs() + S.getNumInputs();
|
|
|
|
for (unsigned i = 0, e = S.getNumInputs(); i != e; i++) {
|
|
const Expr *InputExpr = S.getInputExpr(i);
|
|
|
|
TargetInfo::ConstraintInfo &Info = InputConstraintInfos[i];
|
|
|
|
if (!Constraints.empty())
|
|
Constraints += ',';
|
|
|
|
// Simplify the input constraint.
|
|
std::string InputConstraint(S.getInputConstraint(i));
|
|
InputConstraint = SimplifyConstraint(InputConstraint.c_str(), Target,
|
|
&OutputConstraintInfos);
|
|
|
|
InputConstraint =
|
|
AddVariableConstraints(InputConstraint,
|
|
*InputExpr->IgnoreParenNoopCasts(getContext()),
|
|
Target, CGM, S);
|
|
|
|
llvm::Value *Arg = EmitAsmInput(S, Info, InputExpr, Constraints);
|
|
|
|
// If this input argument is tied to a larger output result, extend the
|
|
// input to be the same size as the output. The LLVM backend wants to see
|
|
// the input and output of a matching constraint be the same size. Note
|
|
// that GCC does not define what the top bits are here. We use zext because
|
|
// that is usually cheaper, but LLVM IR should really get an anyext someday.
|
|
if (Info.hasTiedOperand()) {
|
|
unsigned Output = Info.getTiedOperand();
|
|
QualType OutputType = S.getOutputExpr(Output)->getType();
|
|
QualType InputTy = InputExpr->getType();
|
|
|
|
if (getContext().getTypeSize(OutputType) >
|
|
getContext().getTypeSize(InputTy)) {
|
|
// Use ptrtoint as appropriate so that we can do our extension.
|
|
if (isa<llvm::PointerType>(Arg->getType()))
|
|
Arg = Builder.CreatePtrToInt(Arg, IntPtrTy);
|
|
llvm::Type *OutputTy = ConvertType(OutputType);
|
|
if (isa<llvm::IntegerType>(OutputTy))
|
|
Arg = Builder.CreateZExt(Arg, OutputTy);
|
|
else if (isa<llvm::PointerType>(OutputTy))
|
|
Arg = Builder.CreateZExt(Arg, IntPtrTy);
|
|
else {
|
|
assert(OutputTy->isFloatingPointTy() && "Unexpected output type");
|
|
Arg = Builder.CreateFPExt(Arg, OutputTy);
|
|
}
|
|
}
|
|
}
|
|
if (llvm::Type* AdjTy =
|
|
getTargetHooks().adjustInlineAsmType(*this, InputConstraint,
|
|
Arg->getType()))
|
|
Arg = Builder.CreateBitCast(Arg, AdjTy);
|
|
|
|
ArgTypes.push_back(Arg->getType());
|
|
Args.push_back(Arg);
|
|
Constraints += InputConstraint;
|
|
}
|
|
|
|
// Append the "input" part of inout constraints last.
|
|
for (unsigned i = 0, e = InOutArgs.size(); i != e; i++) {
|
|
ArgTypes.push_back(InOutArgTypes[i]);
|
|
Args.push_back(InOutArgs[i]);
|
|
}
|
|
Constraints += InOutConstraints;
|
|
|
|
// Clobbers
|
|
for (unsigned i = 0, e = S.getNumClobbers(); i != e; i++) {
|
|
StringRef Clobber = S.getClobber(i)->getString();
|
|
|
|
if (Clobber != "memory" && Clobber != "cc")
|
|
Clobber = Target.getNormalizedGCCRegisterName(Clobber);
|
|
|
|
if (i != 0 || NumConstraints != 0)
|
|
Constraints += ',';
|
|
|
|
Constraints += "~{";
|
|
Constraints += Clobber;
|
|
Constraints += '}';
|
|
}
|
|
|
|
// Add machine specific clobbers
|
|
std::string MachineClobbers = Target.getClobbers();
|
|
if (!MachineClobbers.empty()) {
|
|
if (!Constraints.empty())
|
|
Constraints += ',';
|
|
Constraints += MachineClobbers;
|
|
}
|
|
|
|
llvm::Type *ResultType;
|
|
if (ResultRegTypes.empty())
|
|
ResultType = VoidTy;
|
|
else if (ResultRegTypes.size() == 1)
|
|
ResultType = ResultRegTypes[0];
|
|
else
|
|
ResultType = llvm::StructType::get(getLLVMContext(), ResultRegTypes);
|
|
|
|
llvm::FunctionType *FTy =
|
|
llvm::FunctionType::get(ResultType, ArgTypes, false);
|
|
|
|
llvm::InlineAsm *IA =
|
|
llvm::InlineAsm::get(FTy, AsmString, Constraints,
|
|
S.isVolatile() || S.getNumOutputs() == 0);
|
|
llvm::CallInst *Result = Builder.CreateCall(IA, Args);
|
|
Result->addAttribute(~0, llvm::Attribute::NoUnwind);
|
|
|
|
// Slap the source location of the inline asm into a !srcloc metadata on the
|
|
// call.
|
|
Result->setMetadata("srcloc", getAsmSrcLocInfo(S.getAsmString(), *this));
|
|
|
|
// Extract all of the register value results from the asm.
|
|
std::vector<llvm::Value*> RegResults;
|
|
if (ResultRegTypes.size() == 1) {
|
|
RegResults.push_back(Result);
|
|
} else {
|
|
for (unsigned i = 0, e = ResultRegTypes.size(); i != e; ++i) {
|
|
llvm::Value *Tmp = Builder.CreateExtractValue(Result, i, "asmresult");
|
|
RegResults.push_back(Tmp);
|
|
}
|
|
}
|
|
|
|
for (unsigned i = 0, e = RegResults.size(); i != e; ++i) {
|
|
llvm::Value *Tmp = RegResults[i];
|
|
|
|
// If the result type of the LLVM IR asm doesn't match the result type of
|
|
// the expression, do the conversion.
|
|
if (ResultRegTypes[i] != ResultTruncRegTypes[i]) {
|
|
llvm::Type *TruncTy = ResultTruncRegTypes[i];
|
|
|
|
// Truncate the integer result to the right size, note that TruncTy can be
|
|
// a pointer.
|
|
if (TruncTy->isFloatingPointTy())
|
|
Tmp = Builder.CreateFPTrunc(Tmp, TruncTy);
|
|
else if (TruncTy->isPointerTy() && Tmp->getType()->isIntegerTy()) {
|
|
uint64_t ResSize = CGM.getTargetData().getTypeSizeInBits(TruncTy);
|
|
Tmp = Builder.CreateTrunc(Tmp,
|
|
llvm::IntegerType::get(getLLVMContext(), (unsigned)ResSize));
|
|
Tmp = Builder.CreateIntToPtr(Tmp, TruncTy);
|
|
} else if (Tmp->getType()->isPointerTy() && TruncTy->isIntegerTy()) {
|
|
uint64_t TmpSize =CGM.getTargetData().getTypeSizeInBits(Tmp->getType());
|
|
Tmp = Builder.CreatePtrToInt(Tmp,
|
|
llvm::IntegerType::get(getLLVMContext(), (unsigned)TmpSize));
|
|
Tmp = Builder.CreateTrunc(Tmp, TruncTy);
|
|
} else if (TruncTy->isIntegerTy()) {
|
|
Tmp = Builder.CreateTrunc(Tmp, TruncTy);
|
|
} else if (TruncTy->isVectorTy()) {
|
|
Tmp = Builder.CreateBitCast(Tmp, TruncTy);
|
|
}
|
|
}
|
|
|
|
EmitStoreThroughLValue(RValue::get(Tmp), ResultRegDests[i]);
|
|
}
|
|
}
|