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/DebugInfo/X86/empty-and-one-elem-array.ll b/llvm/test/DebugInfo/X86/empty-and-one-elem-array.ll
index 5af235f..550a231 100644
--- a/llvm/test/DebugInfo/X86/empty-and-one-elem-array.ll
+++ b/llvm/test/DebugInfo/X86/empty-and-one-elem-array.ll
@@ -5,7 +5,7 @@
%struct.foo = type { i32, [1 x i32] }
%struct.bar = type { i32, [0 x i32] }
-define i32 @func() nounwind uwtable ssp {
+define i32 @func() nounwind uwtable ssp !dbg !5 {
entry:
%my_foo = alloca %struct.foo, align 4
%my_bar = alloca %struct.bar, align 4
@@ -66,7 +66,7 @@
!0 = distinct !DICompileUnit(language: DW_LANG_C99, producer: "clang version 3.3 (trunk 169136)", isOptimized: false, emissionKind: 0, file: !32, enums: !1, retainedTypes: !1, subprograms: !3, globals: !1, imports: !1)
!1 = !{}
!3 = !{!5}
-!5 = distinct !DISubprogram(name: "func", line: 11, isLocal: false, isDefinition: true, virtualIndex: 6, isOptimized: false, scopeLine: 11, file: !6, scope: !6, type: !7, function: i32 ()* @func, variables: !1)
+!5 = distinct !DISubprogram(name: "func", line: 11, isLocal: false, isDefinition: true, virtualIndex: 6, isOptimized: false, scopeLine: 11, file: !6, scope: !6, type: !7, variables: !1)
!6 = !DIFile(filename: "test.c", directory: "/Volumes/Sandbox/llvm")
!7 = !DISubroutineType(types: !8)
!8 = !{!9}