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Minor refactor to make applying patches from 'Add a "probe-stack" attribute' review thread out of order easier.

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git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@216241 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Philip Reames 2014-08-21 22:53:49 +00:00
parent c7260209a8
commit daebbe217e
1 changed files with 5 additions and 1 deletions
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6
lib/Target/X86/X86FrameLowering.cpp
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@ -502,6 +502,8 @@ void X86FrameLowering::emitPrologue(MachineFunction &MF) const {
X86FI->setCalleeSavedFrameSize(
X86FI->getCalleeSavedFrameSize() - TailCallReturnAddrDelta);
bool UseStackProbe = (STI.isOSWindows() && !STI.isTargetMacho());
// If this is x86-64 and the Red Zone is not disabled, if we are a leaf
// function, and use up to 128 bytes of stack space, don't have a frame
// pointer, calls, or dynamic alloca then we do not need to adjust the
@ -675,6 +677,8 @@ void X86FrameLowering::emitPrologue(MachineFunction &MF) const {
// Adjust stack pointer: ESP -= numbytes.
static const size_t PageSize = 4096;
// 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
@ -683,7 +687,7 @@ void X86FrameLowering::emitPrologue(MachineFunction &MF) const {
// 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 && STI.isOSWindows() && !STI.isTargetMacho()) {
if (NumBytes >= PageSize && UseStackProbe) {
const char *StackProbeSymbol;
unsigned CallOp;