llvm-mirror/test/Assembler/drop-debug-info.ll
Peter Collingbourne 5b721561aa 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

llvm-svn: 252219
2015-11-05 22:03:56 +00:00

30 lines
1.4 KiB
LLVM

; RUN: llvm-as < %s -o %t.bc 2>&1 >/dev/null | FileCheck -check-prefix=WARN %s
; RUN: llvm-dis < %t.bc | FileCheck %s
; RUN: verify-uselistorder < %t.bc
define i32 @main() !dbg !4 {
entry:
%retval = alloca i32, align 4
store i32 0, i32* %retval
ret i32 0, !dbg !12
}
!llvm.dbg.cu = !{!0}
!llvm.module.flags = !{!9}
!0 = distinct !DICompileUnit(language: DW_LANG_C99, producer: "clang version 3.5 (trunk 195495) (llvm/trunk 195495:195504M)", isOptimized: false, emissionKind: 0, file: !1, enums: !2, retainedTypes: !2, subprograms: !3, globals: !2, imports: !2)
!1 = !DIFile(filename: "../llvm/tools/clang/test/CodeGen/debug-info-version.c", directory: "/Users/manmanren/llvm_gmail/release")
!2 = !{i32 0}
!3 = !{!4}
!4 = distinct !DISubprogram(name: "main", line: 3, isLocal: false, isDefinition: true, virtualIndex: 6, flags: DIFlagPrototyped, isOptimized: false, scopeLine: 3, file: !1, scope: !5, type: !6, variables: !2)
!5 = !DIFile(filename: "../llvm/tools/clang/test/CodeGen/debug-info-version.c", directory: "/Users/manmanren/llvm_gmail/release")
!6 = !DISubroutineType(types: !7)
!7 = !{!8}
!8 = !DIBasicType(tag: DW_TAG_base_type, name: "int", size: 32, align: 32, encoding: DW_ATE_signed)
!9 = !{i32 2, !"Dwarf Version", i32 2}
!12 = !DILocation(line: 4, scope: !4)
; WARN: warning: ignoring debug info with an invalid version (0)
; CHECK-NOT: !dbg
; CHECK-NOT: !llvm.dbg.cu