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/Transforms/AddDiscriminators/basic.ll b/llvm/test/Transforms/AddDiscriminators/basic.ll
index 6e6c523..cd7455b 100644
--- a/llvm/test/Transforms/AddDiscriminators/basic.ll
+++ b/llvm/test/Transforms/AddDiscriminators/basic.ll
@@ -11,7 +11,7 @@
; if (i < 10) x = i;
; }
-define void @foo(i32 %i) #0 {
+define void @foo(i32 %i) #0 !dbg !4 {
entry:
%i.addr = alloca i32, align 4
%x = alloca i32, align 4
@@ -45,7 +45,7 @@
!1 = !DIFile(filename: "basic.c", directory: ".")
!2 = !{}
!3 = !{!4}
-!4 = distinct !DISubprogram(name: "foo", line: 1, isLocal: false, isDefinition: true, virtualIndex: 6, flags: DIFlagPrototyped, isOptimized: false, scopeLine: 1, file: !1, scope: !5, type: !6, function: void (i32)* @foo, variables: !2)
+!4 = distinct !DISubprogram(name: "foo", line: 1, isLocal: false, isDefinition: true, virtualIndex: 6, flags: DIFlagPrototyped, isOptimized: false, scopeLine: 1, file: !1, scope: !5, type: !6, variables: !2)
!5 = !DIFile(filename: "basic.c", directory: ".")
!6 = !DISubroutineType(types: !2)
!7 = !{i32 2, !"Dwarf Version", i32 4}