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[DwarfEhPrepare] Assign dummy debug location for inserted _Unwind_Resume calls (PR57469)

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DwarfEhPrepare inserts calls to _Unwind_Resume into landing pads.
If _Unwind_Resume happens to be defined in the same module and
debug info is used, then this leads to a verifier error:

  inlinable function call in a function with debug info must
    have a !dbg location
  call void @_Unwind_Resume(ptr %exn.obj) #0

Fix this by assigning a dummy location to the call. (As this
happens in the backend, inlining is not actually relevant here.)

Fixes https://github.com/llvm/llvm-project/issues/57469.

Differential Revision: https://reviews.llvm.org/D133095

(cherry picked from commit 5134bd432f8c35c87f4c4dc3bb744d396adcab58)
This commit is contained in:
Nikita Popov 2022-09-01 10:13:35 +02:00 committed by Tobias Hieta
parent 3a08ad21ce
commit 1a5c5e0f67
2 changed files with 72 additions and 0 deletions
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8
llvm/lib/CodeGen/DwarfEHPrepare.cpp
View file

@ -25,6 +25,7 @@
#include "llvm/CodeGen/TargetSubtargetInfo.h"
#include "llvm/IR/BasicBlock.h"
#include "llvm/IR/Constants.h"
#include "llvm/IR/DebugInfoMetadata.h"
#include "llvm/IR/DerivedTypes.h"
#include "llvm/IR/Dominators.h"
#include "llvm/IR/Function.h"
@ -247,6 +248,13 @@ bool DwarfEHPrepare::InsertUnwindResumeCalls() {
// Call the rewind function.
CallInst *CI =
CallInst::Create(RewindFunction, RewindFunctionArgs, "", UnwindBB);
// The verifier requires that all calls of debug-info-bearing functions
// from debug-info-bearing functions have a debug location (for inlining
// purposes). Assign a dummy location to satisfy the constraint.
Function *RewindFn = dyn_cast<Function>(RewindFunction.getCallee());
if (RewindFn && RewindFn->getSubprogram())
if (DISubprogram *SP = F.getSubprogram())
CI->setDebugLoc(DILocation::get(SP->getContext(), 0, 0, SP));
CI->setCallingConv(RewindFunctionCallingConv);
// We never expect _Unwind_Resume to return.

64
llvm/test/CodeGen/X86/dwarf-eh-prepare-dbg.ll Normal file
View file

@ -0,0 +1,64 @@
; NOTE: Assertions have been autogenerated by utils/update_test_checks.py
; RUN: opt -S -mtriple=x86_64-linux-gnu -dwarfehprepare < %s | FileCheck %s
; PR57469: If _Unwind_Resume is defined in the same module and we have debug
; info, then the inserted _Unwind_Resume calls also need to have a dummy debug
; location to satisfy inlining requirements.
define void @_Unwind_Resume(ptr %ptr) !dbg !4 {
; CHECK-LABEL: @_Unwind_Resume(
; CHECK-NEXT: ret void, !dbg [[DBG11:![0-9]+]]
;
ret void, !dbg !11
}
declare i32 @__gxx_personality_v0(...)
declare void @might_throw()
define void @simple_cleanup_catch() personality ptr @__gxx_personality_v0 !dbg !12 {
; CHECK-LABEL: @simple_cleanup_catch(
; CHECK-NEXT: invoke void @might_throw()
; CHECK-NEXT: to label [[EXIT:%.*]] unwind label [[LANDINGPAD:%.*]], !dbg [[DBG15:![0-9]+]]
; CHECK: exit:
; CHECK-NEXT: ret void
; CHECK: landingpad:
; CHECK-NEXT: [[EX:%.*]] = landingpad { ptr, i32 }
; CHECK-NEXT: cleanup
; CHECK-NEXT: [[EXN_OBJ:%.*]] = extractvalue { ptr, i32 } [[EX]], 0
; CHECK-NEXT: call void @_Unwind_Resume(ptr [[EXN_OBJ]]) #[[ATTR0:[0-9]+]], !dbg [[DBG16:![0-9]+]]
; CHECK-NEXT: unreachable
;
invoke void @might_throw()
to label %exit unwind label %landingpad, !dbg !15
exit:
ret void
landingpad:
%ex = landingpad { ptr, i32 }
cleanup
resume { ptr, i32 } %ex
}
!llvm.dbg.cu = !{!0}
!llvm.module.flags = !{!2, !3}
!0 = distinct !DICompileUnit(language: DW_LANG_C99, file: !1, producer: "clang version 16.0.0 (https://github.com/llvm/llvm-project.git a4c8fb9d1f46f30c66a9ca0dd07c7933f338bb34)", isOptimized: true, runtimeVersion: 0, emissionKind: FullDebug, splitDebugInlining: false, nameTableKind: None)
!1 = !DIFile(filename: "/app/example.c", directory: "/app")
!2 = !{i32 7, !"Dwarf Version", i32 4}
!3 = !{i32 2, !"Debug Info Version", i32 3}
!4 = distinct !DISubprogram(name: "_Unwind_Resume", scope: !5, file: !5, line: 1, type: !6, scopeLine: 1, flags: DIFlagPrototyped | DIFlagAllCallsDescribed, spFlags: DISPFlagDefinition | DISPFlagOptimized, unit: !0, retainedNodes: !9)
!5 = !DIFile(filename: "example.c", directory: "/app")
!6 = !DISubroutineType(types: !7)
!7 = !{null, !8}
!8 = !DIDerivedType(tag: DW_TAG_pointer_type, baseType: null, size: 64)
!9 = !{!10}
!10 = !DILocalVariable(name: "exception", arg: 1, scope: !4, file: !5, line: 1, type: !8)
!11 = !DILocation(line: 2, column: 1, scope: !4)
!12 = distinct !DISubprogram(name: "test", scope: !5, file: !5, line: 4, type: !13, scopeLine: 4, flags: DIFlagAllCallsDescribed, spFlags: DISPFlagDefinition | DISPFlagOptimized, unit: !0)
!13 = !DISubroutineType(types: !14)
!14 = !{null}
!15 = !DILocation(line: 6, column: 1, scope: !12)
; CHECK: [[DBG_SCOPE:![0-9]+]] = distinct !DISubprogram(name: "test"
; CHECK: [[DBG16]] = !DILocation(line: 0, scope: [[DBG_SCOPE]])