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Properly emit __chkstk call instead of __alloca on non-mingw windows targets.

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Patch by Cameron Esfahani!

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@112902 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Anton Korobeynikov
2010-09-02 23:03:46 +00:00
parent 831c8ec016
commit ace53f2fbc
3 changed files with 66 additions and 8 deletions
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25
lib/Target/X86/X86RegisterInfo.cpp
View File

@@ -764,7 +764,7 @@ void mergeSPUpdatesUp(MachineBasicBlock &MBB, MachineBasicBlock::iterator &MBBI,
}
}
/// mergeSPUpdatesUp - Merge two stack-manipulating instructions lower iterator.
/// mergeSPUpdatesDown - Merge two stack-manipulating instructions lower iterator.
static
void mergeSPUpdatesDown(MachineBasicBlock &MBB,
MachineBasicBlock::iterator &MBBI,
@@ -1087,7 +1087,17 @@ void X86RegisterInfo::emitPrologue(MachineFunction &MF) const {
DL = MBB.findDebugLoc(MBBI);
// Adjust stack pointer: ESP -= numbytes.
if (NumBytes >= 4096 && Subtarget->isTargetCygMing()) {
// Windows and cygwin/mingw require a prologue helper routine when allocating
// more than 4K bytes on the stack. Windows uses __chkstk and cygwin/mingw
// uses __alloca. __alloca and the 32-bit version of __chkstk will probe
// the stack and adjust the stack pointer in one go. The 64-bit version
// of __chkstk is only responsible for probing the stack. The 64-bit
// prologue is responsible for adjusting the stack pointer. Touching the
// stack at 4K increments is necessary to ensure that the guard pages used
// by the OS virtual memory manager are allocated in correct sequence.
if (NumBytes >= 4096 &&
(Subtarget->isTargetCygMing() || Subtarget->isTargetWin32())) {
// Check, whether EAX is livein for this function.
bool isEAXAlive = false;
for (MachineRegisterInfo::livein_iterator
@@ -1098,15 +1108,14 @@ void X86RegisterInfo::emitPrologue(MachineFunction &MF) const {
Reg == X86::AH || Reg == X86::AL);
}
// Function prologue calls _alloca to probe the stack when allocating more
// than 4k bytes in one go. Touching the stack at 4K increments is necessary
// to ensure that the guard pages used by the OS virtual memory manager are
// allocated in correct sequence.
const char *StackProbeSymbol =
Subtarget->isTargetWindows() ? "_chkstk" : "_alloca";
if (!isEAXAlive) {
BuildMI(MBB, MBBI, DL, TII.get(X86::MOV32ri), X86::EAX)
.addImm(NumBytes);
BuildMI(MBB, MBBI, DL, TII.get(X86::CALLpcrel32))
.addExternalSymbol("_alloca")
.addExternalSymbol(StackProbeSymbol)
.addReg(StackPtr, RegState::Define | RegState::Implicit)
.addReg(X86::EFLAGS, RegState::Define | RegState::Implicit);
} else {
@@ -1119,7 +1128,7 @@ void X86RegisterInfo::emitPrologue(MachineFunction &MF) const {
BuildMI(MBB, MBBI, DL, TII.get(X86::MOV32ri), X86::EAX)
.addImm(NumBytes - 4);
BuildMI(MBB, MBBI, DL, TII.get(X86::CALLpcrel32))
.addExternalSymbol("_alloca")
.addExternalSymbol(StackProbeSymbol)
.addReg(StackPtr, RegState::Define | RegState::Implicit)
.addReg(X86::EFLAGS, RegState::Define | RegState::Implicit);

4
lib/Target/X86/X86Subtarget.h
View File

@@ -186,6 +186,10 @@ public:
return Is64Bit && (isTargetMingw() || isTargetWindows());
}
bool isTargetWin32() const {
return !Is64Bit && (isTargetMingw() || isTargetWindows());
}
std::string getDataLayout() const {
const char *p;
if (is64Bit())