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/CodeGen/Hexagon/hwloop-dbg.ll b/llvm/test/CodeGen/Hexagon/hwloop-dbg.ll
index af208b3..341f8db 100644
--- a/llvm/test/CodeGen/Hexagon/hwloop-dbg.ll
+++ b/llvm/test/CodeGen/Hexagon/hwloop-dbg.ll
@@ -3,7 +3,7 @@
target datalayout = "e-p:32:32:32-i64:64:64-i32:32:32-i16:16:16-i1:32:32-f64:64:64-f32:32:32-v64:64:64-v32:32:32-a0:0-n16:32"
target triple = "hexagon"
-define void @foo(i32* nocapture %a, i32* nocapture %b) nounwind {
+define void @foo(i32* nocapture %a, i32* nocapture %b) nounwind !dbg !5 {
entry:
tail call void @llvm.dbg.value(metadata i32* %a, i64 0, metadata !13, metadata !DIExpression()), !dbg !17
tail call void @llvm.dbg.value(metadata i32* %b, i64 0, metadata !14, metadata !DIExpression()), !dbg !18
@@ -40,7 +40,7 @@
!0 = distinct !DICompileUnit(language: DW_LANG_C99, producer: "QuIC LLVM Hexagon Clang version 6.1-pre-unknown, (git://git-hexagon-aus.quicinc.com/llvm/clang-mainline.git e9382867661454cdf44addb39430741578e9765c) (llvm/llvm-mainline.git 36412bb1fcf03ed426d4437b41198bae066675ac)", isOptimized: true, emissionKind: 1, file: !28, enums: !2, retainedTypes: !2, subprograms: !3, globals: !2)
!2 = !{}
!3 = !{!5}
-!5 = distinct !DISubprogram(name: "foo", line: 1, isLocal: false, isDefinition: true, virtualIndex: 6, flags: DIFlagPrototyped, isOptimized: true, scopeLine: 1, file: !28, scope: null, type: !7, function: void (i32*, i32*)* @foo, variables: !11)
+!5 = distinct !DISubprogram(name: "foo", line: 1, isLocal: false, isDefinition: true, virtualIndex: 6, flags: DIFlagPrototyped, isOptimized: true, scopeLine: 1, file: !28, scope: null, type: !7, variables: !11)
!6 = !DIFile(filename: "hwloop-dbg.c", directory: "/usr2/kparzysz/s.hex/t")
!7 = !DISubroutineType(types: !8)
!8 = !{null, !9, !9}