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Notify the linker when a TU compiled with split-stack has a function without a prologue.

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More context here: https://go-review.googlesource.com/c/go/+/148819/

llvm-svn: 347614
This commit is contained in:
Sterling Augustine 2018-11-26 23:26:31 +00:00
parent 89a000d03a
commit 567aedab5a
3 changed files with 46 additions and 4 deletions
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10
lib/Target/ARM/ARMFrameLowering.cpp
View File

@ -2157,9 +2157,15 @@ void ARMFrameLowering::adjustForSegmentedStacks(
// Do not generate a prologue for leaf functions with a stack of size zero.
// For non-leaf functions we have to allow for the possibility that the
// call is to a non-split function, as in PR37807.
if (StackSize == 0 && !MFI.hasTailCall())
// callis to a non-split function, as in PR37807. This function could also
// take the address of a non-split function. When the linker tries to adjust
// its non-existent prologue, it would fail with an error. Mark the object
// file so that such failures are not errors. See this Go language bug-report
// https://go-review.googlesource.com/c/go/+/148819/
if (StackSize == 0 && !MFI.hasTailCall()) {
MF.getMMI().setHasNosplitStack(true);
return;
}
// Use R4 and R5 as scratch registers.
// We save R4 and R5 before use and restore them before leaving the function.

10
lib/Target/X86/X86FrameLowering.cpp
View File

@ -2270,9 +2270,15 @@ void X86FrameLowering::adjustForSegmentedStacks(
// Do not generate a prologue for leaf functions with a stack of size zero.
// For non-leaf functions we have to allow for the possibility that the
// call is to a non-split function, as in PR37807.
if (StackSize == 0 && !MFI.hasTailCall())
// callis to a non-split function, as in PR37807. This function could also
// take the address of a non-split function. When the linker tries to adjust
// its non-existent prologue, it would fail with an error. Mark the object
// file so that such failures are not errors. See this Go language bug-report
// https://go-review.googlesource.com/c/go/+/148819/
if (StackSize == 0 && !MFI.hasTailCall()) {
MF.getMMI().setHasNosplitStack(true);
return;
}
MachineBasicBlock *allocMBB = MF.CreateMachineBasicBlock();
MachineBasicBlock *checkMBB = MF.CreateMachineBasicBlock();

30
test/CodeGen/X86/segmented-stacks-standalone.ll Normal file
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@ -0,0 +1,30 @@
; RUN: llc < %s -mcpu=generic -mtriple=i686-linux -verify-machineinstrs | FileCheck %s -check-prefix=X32-Linux
; RUN: llc < %s -mcpu=generic -mtriple=x86_64-linux -verify-machineinstrs | FileCheck %s -check-prefix=X64-Linux
; This test is standalone because segmented-stacks.ll generates
; object-files with both .note.GNU-split-stack (for the split-stack
; functions) and .note.GNU-no-split-stack sections (for the
; non-split-stack functions). But a split-stack function without a
; stack frame should have a .note.GNU-split-stack section regardless
; of any other contents of the compilation unit.
define void @test_nostack() #0 {
ret void
}
attributes #0 = { "split-stack" }
; X32-Linux: .section ".note.GNU-split-stack","",@progbits
; X32-Linux: .section ".note.GNU-no-split-stack","",@progbits
; X64-Linux: .section ".note.GNU-split-stack","",@progbits
; X64-Linux: .section ".note.GNU-no-split-stack","",@progbits
; X64-FreeBSD: .section ".note.GNU-split-stack","",@progbits
; X64-FreeBSD: .section ".note.GNU-no-split-stack","",@progbits
; X32-DFlyBSD: .section ".note.GNU-split-stack","",@progbits
; X32-DFlyBSD: .section ".note.GNU-no-split-stack","",@progbits
; X64-DFlyBSD: .section ".note.GNU-split-stack","",@progbits
; X64-DFlyBSD: .section ".note.GNU-no-split-stack","",@progbits