[X86] Don't try to generate direct calls to TLS globals

[oota-llvm.git] / lib / Target / X86 / X86FrameLowering.cpp

diff --git a/lib/Target/X86/X86FrameLowering.cpp b/lib/Target/X86/X86FrameLowering.cpp
index 8779acc6a08bcecabf3b05653cbf69e59f08adb1..16aab16d63ee41a687b74501df1841f961c29159 100644 (file)
--- a/lib/Target/X86/X86FrameLowering.cpp
+++ b/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;