diff options
Diffstat (limited to 'llvm/lib/Target/X86/X86FrameLowering.cpp')
| -rw-r--r-- | llvm/lib/Target/X86/X86FrameLowering.cpp | 12 |
1 files changed, 9 insertions, 3 deletions
diff --git a/llvm/lib/Target/X86/X86FrameLowering.cpp b/llvm/lib/Target/X86/X86FrameLowering.cpp index 8779acc6a08..16aab16d63e 100644 --- a/llvm/lib/Target/X86/X86FrameLowering.cpp +++ b/llvm/lib/Target/X86/X86FrameLowering.cpp @@ -528,6 +528,14 @@ void X86FrameLowering::emitPrologue(MachineFunction &MF) const { bool UseStackProbe = (STI.isOSWindows() && !STI.isTargetMachO()); + // The default stack probe size is 4096 if the function has no stackprobesize + // attribute. + unsigned StackProbeSize = 4096; + if (Fn->hasFnAttribute("stack-probe-size")) + Fn->getFnAttribute("stack-probe-size") + .getValueAsString() + .getAsInteger(0, StackProbeSize); + // 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 @@ -705,8 +713,6 @@ 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 @@ -715,7 +721,7 @@ 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 >= PageSize && UseStackProbe) { + if (NumBytes >= StackProbeSize && UseStackProbe) { const char *StackProbeSymbol; unsigned CallOp; |
