This is an archive of the discontinued LLVM Phabricator instance.

[CodeGen][shrinkWrapping] Implement the no-shrink-wrap function attribute.
Needs ReviewPublic

Authored by sdardis on Jun 12 2018, 2:24 AM.

Reviewers

efriedma
javed.absar

Summary

Counterpart to D47829.

Repository

rL LLVM

Build Status

Buildable 19215
Build 19215: arc lint + arc unit

Path

Size

lib/

CodeGen/

5 lines

test/

CodeGen/

AArch64/

13 lines

Show First 20 Lines • Show All 578 Lines • ▼ Show 20 Lines	bool ShrinkWrap::runOnMachineFunction(MachineFunction &MF) {
MFI.setRestorePoint(Restore);		MFI.setRestorePoint(Restore);
++NumCandidates;		++NumCandidates;
return false;		return false;
}		}

bool ShrinkWrap::isShrinkWrapEnabled(const MachineFunction &MF) {		bool ShrinkWrap::isShrinkWrapEnabled(const MachineFunction &MF) {
const TargetFrameLowering *TFI = MF.getSubtarget().getFrameLowering();		const TargetFrameLowering *TFI = MF.getSubtarget().getFrameLowering();

		if (MF.getFunction()
		.getFnAttribute("no-shrink-wrap")
		.getValueAsString() == "true")
		return false;

switch (EnableShrinkWrapOpt) {		switch (EnableShrinkWrapOpt) {
case cl::BOU_UNSET:		case cl::BOU_UNSET:
return TFI->enableShrinkWrapping(MF) &&		return TFI->enableShrinkWrapping(MF) &&
// Windows with CFI has some limitations that make it impossible		// Windows with CFI has some limitations that make it impossible
// to use shrink-wrapping.		// to use shrink-wrapping.
!MF.getTarget().getMCAsmInfo()->usesWindowsCFI() &&		!MF.getTarget().getMCAsmInfo()->usesWindowsCFI() &&
// Sanitizers look at the value of the stack at the location		// Sanitizers look at the value of the stack at the location
// of the crash. Since a crash can happen anywhere, the		// of the crash. Since a crash can happen anywhere, the
Show All 16 Lines

				; RUN: llc < %s -mtriple=aarch64-linux-gnu -O3 -o - 2>&1 -debug \| FileCheck %s

				; Test the no-shrink-wrap attribute.

				; CHECK-NOT: Nothing to shrink-wrap

				define void @m() #0 {
				entry:
				ret void
				}

				attributes #0 = { "no-shrink-wrap"="true" }