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/LoopVectorize/control-flow.ll b/llvm/test/Transforms/LoopVectorize/control-flow.ll
index 2f2b1fd..a2fc69a 100644
--- a/llvm/test/Transforms/LoopVectorize/control-flow.ll
+++ b/llvm/test/Transforms/LoopVectorize/control-flow.ll
@@ -20,7 +20,7 @@
target datalayout = "e-m:o-i64:64-f80:128-n8:16:32:64-S128"
; Function Attrs: nounwind optsize ssp uwtable
-define i32 @_Z4testPii(i32* nocapture %A, i32 %Length) #0 {
+define i32 @_Z4testPii(i32* nocapture %A, i32 %Length) #0 !dbg !4 {
entry:
%cmp8 = icmp sgt i32 %Length, 0, !dbg !10
br i1 %cmp8, label %for.body.preheader, label %end, !dbg !10
@@ -59,7 +59,7 @@
!1 = !DIFile(filename: "source.cpp", directory: ".")
!2 = !{}
!3 = !{!4}
-!4 = distinct !DISubprogram(name: "test", line: 1, isLocal: false, isDefinition: true, virtualIndex: 6, flags: DIFlagPrototyped, isOptimized: true, scopeLine: 2, file: !1, scope: !5, type: !6, function: i32 (i32*, i32)* @_Z4testPii, variables: !2)
+!4 = distinct !DISubprogram(name: "test", line: 1, isLocal: false, isDefinition: true, virtualIndex: 6, flags: DIFlagPrototyped, isOptimized: true, scopeLine: 2, file: !1, scope: !5, type: !6, variables: !2)
!5 = !DIFile(filename: "source.cpp", directory: ".")
!6 = !DISubroutineType(types: !2)
!7 = !{i32 2, !"Dwarf Version", i32 2}