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[PS4] Guarantee an instruction after a 'noreturn' call.

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We need the "return address" of a noreturn call to be within the
bounds of the calling function; TrapUnreachable turns 'unreachable'
into a 'ud2' instruction, which has that desired effect.

Differential Revision: http://reviews.llvm.org/D18414


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@264224 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Paul Robinson 2016-03-24 00:10:03 +00:00
parent 6f5ddf8965
commit d0c6d209f8
3 changed files with 45 additions and 1 deletions
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4
lib/Target/X86/X86TargetMachine.cpp
View File

@ -119,7 +119,9 @@ X86TargetMachine::X86TargetMachine(const Target &T, const Triple &TT,
// after a call to 'noreturn' function.
// To prevent that, we emit a trap for 'unreachable' IR instructions.
// (which on X86, happens to be the 'ud2' instruction)
if (Subtarget.isTargetWin64())
// On PS4, the "return address" of a 'noreturn' call must still be within
// the calling function, and TrapUnreachable is an easy way to get that.
if (Subtarget.isTargetWin64() || Subtarget.isTargetPS4())
this->Options.TrapUnreachable = true;
// By default (and when -ffast-math is on), enable estimate codegen for

4
test/CodeGen/X86/br-fold.ll
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@ -2,6 +2,7 @@
; RUN: llc -mtriple=x86_64-pc-linux < %s | FileCheck -check-prefix=X64_LINUX %s
; RUN: llc -mtriple=x86_64-pc-windows < %s | FileCheck -check-prefix=X64_WINDOWS %s
; RUN: llc -mtriple=x86_64-pc-windows-gnu < %s | FileCheck -check-prefix=X64_WINDOWS_GNU %s
; RUN: llc -mtriple=x86_64-scei-ps4 < %s | FileCheck -check-prefix=PS4 %s
; X64_DARWIN: orq
; X64_DARWIN-NEXT: %bb8.i329
@ -15,6 +16,9 @@
; X64_WINDOWS_GNU: orq %rax, %rcx
; X64_WINDOWS_GNU-NEXT: ud2
; PS4: orq %rax, %rcx
; PS4-NEXT: ud2
@_ZN11xercesc_2_513SchemaSymbols21fgURI_SCHEMAFORSCHEMAE = external constant [33 x i16], align 32 ; <[33 x i16]*> [#uses=1]
@_ZN11xercesc_2_56XMLUni16fgNotationStringE = external constant [9 x i16], align 16 ; <[9 x i16]*> [#uses=1]

38
test/CodeGen/X86/ps4-noreturn.ll Normal file
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@ -0,0 +1,38 @@
; RUN: llc < %s -mtriple=x86_64-scei-ps4 | FileCheck %s
declare i32 @personality(...)
; Check that after the (implicitly noreturn) unwind call, there is
; another instruction. It was easy to produce 'ud2' so we check for that.
define void @foo1() personality i32 (...)* @personality {
; CHECK-LABEL: foo1:
; CHECK: .cfi_startproc
; CHECK: callq bar
; CHECK: retq
; Check for 'ud2' between noreturn call and function end.
; CHECK: callq _Unwind_Resume
; CHECK-NEXT: ud2
; CHECK-NEXT: .Lfunc_end0:
invoke void @bar()
to label %normal
unwind label %catch
normal:
ret void
catch:
%1 = landingpad { i8*, i32 } cleanup
resume { i8*, i32 } %1
}
declare void @bar() #0
; Similar check after an explicit noreturn call.
define void @foo2() {
; CHECK-LABEL: foo2:
; CHECK: callq bar
; CHECK-NEXT: ud2
; CHECK-NEXT: .Lfunc_end1:
tail call void @bar()
unreachable
}
attributes #0 = { noreturn }