Peter Collingbourne 5f220beefc DI: Reverse direction of subprogram -> function edge.
Previously, subprograms contained a metadata reference to the function they
described. Because most clients need to get or set a subprogram for a given
function rather than the other way around, this created unneeded inefficiency.

For example, many passes needed to call the function llvm::makeSubprogramMap()
to build a mapping from functions to subprograms, and the IR linker needed to
fix up function references in a way that caused quadratic complexity in the IR
linking phase of LTO.

This change reverses the direction of the edge by storing the subprogram as
function-level metadata and removing DISubprogram's function field.

Since this is an IR change, a bitcode upgrade has been provided.

Fixes PR23367. An upgrade script for textual IR for out-of-tree clients is
attached to the PR.

Differential Revision: http://reviews.llvm.org/D14265

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@252219 91177308-0d34-0410-b5e6-96231b3b80d8
2015-11-05 22:03:56 +00:00

56 lines
2.2 KiB
LLVM

; From source:
; int f(int a, int b) {
; return a //
; && //
; b;
; }
; Check that the comparison of 'a' is attributed to line 2, not 3.
; CHECK: .loc{{ +}}1{{ +}}2
; CHECK-NOT: .loc{{ }}
; CHECK: cmp
; Function Attrs: nounwind uwtable
define i32 @_Z1fii(i32 %a, i32 %b) #0 !dbg !4 {
entry:
%a.addr = alloca i32, align 4
%b.addr = alloca i32, align 4
store i32 %a, i32* %a.addr, align 4
store i32 %b, i32* %b.addr, align 4
%0 = load i32, i32* %a.addr, align 4, !dbg !10
%tobool = icmp ne i32 %0, 0, !dbg !10
br i1 %tobool, label %land.rhs, label %land.end, !dbg !11
land.rhs: ; preds = %entry
%1 = load i32, i32* %b.addr, align 4, !dbg !12
%tobool1 = icmp ne i32 %1, 0, !dbg !12
br label %land.end
land.end: ; preds = %land.rhs, %entry
%2 = phi i1 [ false, %entry ], [ %tobool1, %land.rhs ]
%conv = zext i1 %2 to i32, !dbg !10
ret i32 %conv, !dbg !13
}
attributes #0 = { nounwind uwtable "less-precise-fpmad"="false" "no-frame-pointer-elim"="true" "no-frame-pointer-elim-non-leaf" "no-infs-fp-math"="false" "no-nans-fp-math"="false" "stack-protector-buffer-size"="8" "unsafe-fp-math"="false" "use-soft-float"="false" }
!llvm.dbg.cu = !{!0}
!llvm.module.flags = !{!7, !8}
!llvm.ident = !{!9}
!0 = distinct !DICompileUnit(language: DW_LANG_C_plus_plus, producer: "clang version 3.7.0 (trunk 227472) (llvm/trunk 227476)", isOptimized: false, emissionKind: 2, file: !1, enums: !2, retainedTypes: !2, subprograms: !3, globals: !2, imports: !2)
!1 = !DIFile(filename: "line.cpp", directory: "/tmp/dbginfo")
!2 = !{}
!3 = !{!4}
!4 = distinct !DISubprogram(name: "f", line: 1, isLocal: false, isDefinition: true, flags: DIFlagPrototyped, isOptimized: false, scopeLine: 1, file: !1, scope: !5, type: !6, variables: !2)
!5 = !DIFile(filename: "line.cpp", directory: "/tmp/dbginfo")
!6 = !DISubroutineType(types: !2)
!7 = !{i32 2, !"Dwarf Version", i32 4}
!8 = !{i32 2, !"Debug Info Version", i32 3}
!9 = !{!"clang version 3.7.0 (trunk 227472) (llvm/trunk 227476)"}
!10 = !DILocation(line: 2, scope: !4)
!11 = !DILocation(line: 3, scope: !4)
!12 = !DILocation(line: 4, scope: !4)
!13 = !DILocation(line: 2, scope: !4)