#include "llvm/CodeGen/MachineInstrBuilder.h"
#include "llvm/CodeGen/MachineModuleInfo.h"
#include "llvm/CodeGen/MachineRegisterInfo.h"
-#include "llvm/DataLayout.h"
-#include "llvm/Function.h"
+#include "llvm/IR/DataLayout.h"
+#include "llvm/IR/Function.h"
#include "llvm/MC/MCAsmInfo.h"
#include "llvm/MC/MCSymbol.h"
#include "llvm/Support/CommandLine.h"
return CompactUnwindEncoding;
}
+/// usesTheStack - This function checks if any of the users of EFLAGS
+/// copies the EFLAGS. We know that the code that lowers COPY of EFLAGS has
+/// to use the stack, and if we don't adjust the stack we clobber the first
+/// frame index.
+/// See X86InstrInfo::copyPhysReg.
+static bool usesTheStack(MachineFunction &MF) {
+ MachineRegisterInfo &MRI = MF.getRegInfo();
+
+ for (MachineRegisterInfo::reg_iterator ri = MRI.reg_begin(X86::EFLAGS),
+ re = MRI.reg_end(); ri != re; ++ri)
+ if (ri->isCopy())
+ return true;
+
+ return false;
+}
+
/// emitPrologue - Push callee-saved registers onto the stack, which
/// automatically adjust the stack pointer. Adjust the stack pointer to allocate
/// space for local variables. Also emit labels used by the exception handler to
// 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
- // stack pointer (we fit in the Red Zone).
- if (Is64Bit && !Fn->getFnAttributes().hasAttribute(Attribute::NoRedZone) &&
+ // stack pointer (we fit in the Red Zone). We also check that we don't
+ // push and pop from the stack.
+ if (Is64Bit && !Fn->getAttributes().hasAttribute(AttributeSet::FunctionIndex,
+ Attribute::NoRedZone) &&
!RegInfo->needsStackRealignment(MF) &&
!MFI->hasVarSizedObjects() && // No dynamic alloca.
!MFI->adjustsStack() && // No calls.
!IsWin64 && // Win64 has no Red Zone
+ !usesTheStack(MF) && // Don't push and pop.
!MF.getTarget().Options.EnableSegmentedStacks) { // Regular stack
uint64_t MinSize = X86FI->getCalleeSavedFrameSize();
if (HasFP) MinSize += SlotSize;