1
0
mirror of https://github.com/RPCS3/llvm-mirror.git synced 2024-11-24 03:33:20 +01:00
llvm-mirror/test/DebugInfo/X86/stack-args.ll
Adrian Prantl caed503477 EmitFuncArgumentDbgValue: Prefer stack slots over registers for stack arguments
While investigating LLVM PR22316 (http://llvm.org/bugs/show_bug.cgi?id=22316)
I started wondering if it were not always preferable to emit the
initial DBG_VALUEs for stack arguments as FI locations instead of
describing the first register they get copied into. The advantage of
doing this is that the arguments will be available as soon as the
stack is setup. As illustrated by the testcase in the PR, the first
copy of the FI into a register may be sunk by MachineSink.cpp into a
later basic block. By describing the argument on the stack, we nicely
circumvent this problem.

<rdar://problem/19583723>

Differential Revision: https://reviews.llvm.org/D41135

llvm-svn: 320758
2017-12-14 22:55:06 +00:00

77 lines
3.1 KiB
LLVM

; RUN: llc -filetype=obj -o - %s | llvm-dwarfdump - | FileCheck %s
; Generated from:
; void * __attribute__ (( regparm(2) )) f(void *, void *);
; void * __attribute__ (( regparm(0) )) g(void *, void *);
;
; void *g(void *t, void *k) {
; if (k == (void *)0)
; return (void *)0;
; return f(t, k);
; }
; CHECK: DW_TAG_formal_parameter
; CHECK-NEXT: DW_AT_location (DW_OP_fbreg +4)
; CHECK-NEXT: DW_AT_name ("t")
; CHECK: DW_TAG_formal_parameter
; CHECK-NEXT: DW_AT_location (DW_OP_fbreg +8)
; CHECK-NEXT: DW_AT_name ("k")
source_filename = "t.c"
target datalayout = "e-m:e-p:32:32-f64:32:64-f80:32-n8:16:32-S128"
target triple = "i386--linux-gnu"
; Function Attrs: nounwind
define i8* @g(i8* %t, i8* %k) local_unnamed_addr #0 !dbg !10 {
entry:
call void @llvm.dbg.value(metadata i8* %t, metadata !14, metadata !DIExpression()), !dbg !16
call void @llvm.dbg.value(metadata i8* %k, metadata !15, metadata !DIExpression()), !dbg !17
%cmp = icmp eq i8* %k, null, !dbg !18
br i1 %cmp, label %return, label %if.end, !dbg !20
if.end: ; preds = %entry
%call = tail call i8* @f(i8* inreg %t, i8* inreg nonnull %k) #3, !dbg !21
br label %return, !dbg !22
return: ; preds = %entry, %if.end
%retval.0 = phi i8* [ %call, %if.end ], [ null, %entry ]
ret i8* %retval.0, !dbg !23
}
declare i8* @f(i8* inreg, i8* inreg) local_unnamed_addr
; Function Attrs: nounwind readnone speculatable
declare void @llvm.dbg.value(metadata, metadata, metadata) #2
attributes #0 = { nounwind }
attributes #2 = { nounwind readnone speculatable }
attributes #3 = { nounwind }
!llvm.dbg.cu = !{!0}
!llvm.module.flags = !{!5, !6, !7, !8}
!llvm.ident = !{!9}
!0 = distinct !DICompileUnit(language: DW_LANG_C99, file: !1, producer: "clang version 6.0.0 (llvm/trunk 319230)", isOptimized: true, runtimeVersion: 0, emissionKind: FullDebug, enums: !2, retainedTypes: !3)
!1 = !DIFile(filename: "t.c", directory: "/")
!2 = !{}
!3 = !{!4}
!4 = !DIDerivedType(tag: DW_TAG_pointer_type, baseType: null, size: 32)
!5 = !{i32 1, !"NumRegisterParameters", i32 0}
!6 = !{i32 2, !"Dwarf Version", i32 4}
!7 = !{i32 2, !"Debug Info Version", i32 3}
!8 = !{i32 1, !"wchar_size", i32 4}
!9 = !{!"clang version 6.0.0 (llvm/trunk 319230)"}
!10 = distinct !DISubprogram(name: "g", scope: !1, file: !1, line: 4, type: !11, isLocal: false, isDefinition: true, scopeLine: 4, flags: DIFlagPrototyped, isOptimized: true, unit: !0, variables: !13)
!11 = !DISubroutineType(types: !12)
!12 = !{!4, !4, !4}
!13 = !{!14, !15}
!14 = !DILocalVariable(name: "t", arg: 1, scope: !10, file: !1, line: 4, type: !4)
!15 = !DILocalVariable(name: "k", arg: 2, scope: !10, file: !1, line: 4, type: !4)
!16 = !DILocation(line: 4, column: 15, scope: !10)
!17 = !DILocation(line: 4, column: 24, scope: !10)
!18 = !DILocation(line: 5, column: 9, scope: !19)
!19 = distinct !DILexicalBlock(scope: !10, file: !1, line: 5, column: 7)
!20 = !DILocation(line: 5, column: 7, scope: !10)
!21 = !DILocation(line: 7, column: 10, scope: !10)
!22 = !DILocation(line: 7, column: 3, scope: !10)
!23 = !DILocation(line: 8, column: 1, scope: !10)