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
diff --git a/llvm/test/Linker/DbgDeclare2.ll b/llvm/test/Linker/DbgDeclare2.ll
index f3bd85c..2335f12 100644
--- a/llvm/test/Linker/DbgDeclare2.ll
+++ b/llvm/test/Linker/DbgDeclare2.ll
@@ -5,7 +5,7 @@
target datalayout = "e-p:64:64:64-i1:8:8-i8:8:8-i16:16:16-i32:32:32-i64:64:64-f32:32:32-f64:64:64-v64:64:64-v128:128:128-a0:0:64-s0:64:64-f80:128:128-n8:16:32:64-S128"
target triple = "x86_64-apple-macosx10.9.0"
-define void @test(i32 %argc, i8** %argv) uwtable ssp {
+define void @test(i32 %argc, i8** %argv) uwtable ssp !dbg !5 {
entry:
%argc.addr = alloca i32, align 4
%argv.addr = alloca i8**, align 8
@@ -53,7 +53,7 @@
!0 = distinct !DICompileUnit(language: DW_LANG_C_plus_plus, producer: "clang version 3.3 (trunk 173515)", isOptimized: true, emissionKind: 0, file: !25, enums: !2, retainedTypes: !2, subprograms: !3, globals: !2)
!2 = !{}
!3 = !{!5}
-!5 = distinct !DISubprogram(name: "print_args", linkageName: "test", line: 4, isLocal: false, isDefinition: true, virtualIndex: 6, flags: DIFlagPrototyped, isOptimized: false, scopeLine: 5, file: !26, scope: null, type: !7, function: void (i32, i8**)* @test, variables: !2)
+!5 = distinct !DISubprogram(name: "print_args", linkageName: "test", line: 4, isLocal: false, isDefinition: true, virtualIndex: 6, flags: DIFlagPrototyped, isOptimized: false, scopeLine: 5, file: !26, scope: null, type: !7, variables: !2)
!6 = !DIFile(filename: "test.cpp", directory: "/private/tmp")
!7 = !DISubroutineType(types: !8)
!8 = !{null, !9, !10}