126 lines
4.4 KiB
C++
126 lines
4.4 KiB
C++
//===- AssumptionCache.cpp - Cache finding @llvm.assume calls -------------===//
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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 file contains a pass that keeps track of @llvm.assume intrinsics in
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// the functions of a module.
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//
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//===----------------------------------------------------------------------===//
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#include "llvm/Analysis/AssumptionCache.h"
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#include "llvm/IR/CallSite.h"
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#include "llvm/IR/Dominators.h"
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#include "llvm/IR/Function.h"
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#include "llvm/IR/Instructions.h"
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#include "llvm/IR/IntrinsicInst.h"
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#include "llvm/IR/PatternMatch.h"
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#include "llvm/Support/Debug.h"
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using namespace llvm;
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using namespace llvm::PatternMatch;
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void AssumptionCache::scanFunction() {
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assert(!Scanned && "Tried to scan the function twice!");
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assert(AssumeHandles.empty() && "Already have assumes when scanning!");
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// Go through all instructions in all blocks, add all calls to @llvm.assume
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// to this cache.
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for (BasicBlock &B : F)
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for (Instruction &II : B)
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if (match(&II, m_Intrinsic<Intrinsic::assume>()))
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AssumeHandles.push_back(&II);
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// Mark the scan as complete.
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Scanned = true;
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}
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void AssumptionCache::registerAssumption(CallInst *CI) {
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assert(match(CI, m_Intrinsic<Intrinsic::assume>()) &&
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"Registered call does not call @llvm.assume");
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// If we haven't scanned the function yet, just drop this assumption. It will
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// be found when we scan later.
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if (!Scanned)
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return;
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AssumeHandles.push_back(CI);
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#ifndef NDEBUG
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assert(CI->getParent() &&
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"Cannot register @llvm.assume call not in a basic block");
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assert(&F == CI->getParent()->getParent() &&
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"Cannot register @llvm.assume call not in this function");
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// We expect the number of assumptions to be small, so in an asserts build
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// check that we don't accumulate duplicates and that all assumptions point
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// to the same function.
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SmallPtrSet<Value *, 16> AssumptionSet;
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for (auto &VH : AssumeHandles) {
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if (!VH)
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continue;
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assert(&F == cast<Instruction>(VH)->getParent()->getParent() &&
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"Cached assumption not inside this function!");
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assert(match(cast<CallInst>(VH), m_Intrinsic<Intrinsic::assume>()) &&
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"Cached something other than a call to @llvm.assume!");
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assert(AssumptionSet.insert(VH).second &&
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"Cache contains multiple copies of a call!");
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}
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#endif
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}
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void AssumptionCacheTracker::FunctionCallbackVH::deleted() {
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auto I = ACT->AssumptionCaches.find_as(cast<Function>(getValPtr()));
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if (I != ACT->AssumptionCaches.end())
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ACT->AssumptionCaches.erase(I);
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// 'this' now dangles!
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}
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AssumptionCache &AssumptionCacheTracker::getAssumptionCache(Function &F) {
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// We probe the function map twice to try and avoid creating a value handle
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// around the function in common cases. This makes insertion a bit slower,
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// but if we have to insert we're going to scan the whole function so that
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// shouldn't matter.
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auto I = AssumptionCaches.find_as(&F);
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if (I != AssumptionCaches.end())
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return *I->second;
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// Ok, build a new cache by scanning the function, insert it and the value
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// handle into our map, and return the newly populated cache.
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auto IP = AssumptionCaches.insert(std::make_pair(
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FunctionCallbackVH(&F, this), llvm::make_unique<AssumptionCache>(F)));
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assert(IP.second && "Scanning function already in the map?");
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return *IP.first->second;
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}
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void AssumptionCacheTracker::verifyAnalysis() const {
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#ifndef NDEBUG
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SmallPtrSet<const CallInst *, 4> AssumptionSet;
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for (const auto &I : AssumptionCaches) {
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for (auto &VH : I.second->assumptions())
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if (VH)
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AssumptionSet.insert(cast<CallInst>(VH));
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for (const BasicBlock &B : cast<Function>(*I.first))
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for (const Instruction &II : B)
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if (match(&II, m_Intrinsic<Intrinsic::assume>()))
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assert(AssumptionSet.count(cast<CallInst>(&II)) &&
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"Assumption in scanned function not in cache");
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}
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#endif
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}
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AssumptionCacheTracker::AssumptionCacheTracker() : ImmutablePass(ID) {
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initializeAssumptionCacheTrackerPass(*PassRegistry::getPassRegistry());
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}
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AssumptionCacheTracker::~AssumptionCacheTracker() {}
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INITIALIZE_PASS(AssumptionCacheTracker, "assumption-cache-tracker",
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"Assumption Cache Tracker", false, true)
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char AssumptionCacheTracker::ID = 0;
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