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Pull in r183984 from llvm trunk:

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Make PrologEpilogInserter save/restore all callee saved registers in
  functions which call __builtin_unwind_init()

  __builtin_unwind_init() is an undocumented gcc intrinsic which has
  this effect, and is used in libgcc_eh.

  Goes part of the way toward fixing PR8541.

This obsoletes the ugly hack to libgcc's unwind code from r245272, and
should also work for other arches, so revert the hack too.
This commit is contained in:
Dimitry Andric 2013-06-20 18:25:10 +00:00
parent a2feb19b26
commit 707d0cef66
2 changed files with 3 additions and 13 deletions
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12
contrib/gcc/unwind-dw2.c
View File

@ -1438,17 +1438,6 @@ uw_init_context_1 (struct _Unwind_Context *context,
context->ra = __builtin_extract_return_addr (outer_ra);
}
#if defined(__clang__) && defined(__amd64__)
/* Some versions of clang don't save and restore all callee registers, if a
__builtin_eh_return() intrinsic is used in a function. This is particularly
bad on amd64. For now, use the following ugly hack to force it to assume
those registers are clobbered, when invoking __builtin_eh_return(), so it
will emit code to save and restore them. */
#define CLOBBER_REGS_HACK \
__asm __volatile(" " : : : "r15", "r14", "r13", "r12", "rbx", "rdx", "rax");
#else
#define CLOBBER_REGS_HACK
#endif /* __clang__ */
/* Install TARGET into CURRENT so that we can return to it. This is a
macro because __builtin_eh_return must be invoked in the context of
@ -1459,7 +1448,6 @@ uw_init_context_1 (struct _Unwind_Context *context,
{ \
long offset = uw_install_context_1 ((CURRENT), (TARGET)); \
void *handler = __builtin_frob_return_addr ((TARGET)->ra); \
CLOBBER_REGS_HACK \
__builtin_eh_return (offset, handler); \
} \
while (0)

4
contrib/llvm/lib/CodeGen/PrologEpilogInserter.cpp
View File

@ -29,6 +29,7 @@
#include "llvm/CodeGen/MachineFrameInfo.h"
#include "llvm/CodeGen/MachineInstr.h"
#include "llvm/CodeGen/MachineLoopInfo.h"
#include "llvm/CodeGen/MachineModuleInfo.h"
#include "llvm/CodeGen/MachineRegisterInfo.h"
#include "llvm/CodeGen/RegisterScavenging.h"
#include "llvm/IR/InlineAsm.h"
@ -214,7 +215,8 @@ void PEI::calculateCalleeSavedRegisters(MachineFunction &F) {
std::vector<CalleeSavedInfo> CSI;
for (unsigned i = 0; CSRegs[i]; ++i) {
unsigned Reg = CSRegs[i];
if (F.getRegInfo().isPhysRegUsed(Reg)) {
// Functions which call __builtin_unwind_init get all their registers saved.
if (F.getRegInfo().isPhysRegUsed(Reg) || F.getMMI().callsUnwindInit()) {
// If the reg is modified, save it!
CSI.push_back(CalleeSavedInfo(Reg));
}