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/ARM/constant-dbgloc.ll b/llvm/test/DebugInfo/ARM/constant-dbgloc.ll
index 168a8dd..5fd219a 100644
--- a/llvm/test/DebugInfo/ARM/constant-dbgloc.ll
+++ b/llvm/test/DebugInfo/ARM/constant-dbgloc.ll
@@ -13,7 +13,7 @@
; CHECK: mvn
; Function Attrs: nounwind
-define i32 @main() {
+define i32 @main() !dbg !4 {
entry:
%retval = alloca i32, align 4
store i32 0, i32* %retval
@@ -27,7 +27,7 @@
!1 = !DIFile(filename: "test.c", directory: "/home/user/clang/build")
!2 = !{}
!3 = !{!4}
-!4 = distinct !DISubprogram(name: "main", scope: !1, file: !1, line: 2, type: !5, isLocal: false, isDefinition: true, scopeLine: 3, flags: DIFlagPrototyped, isOptimized: false, function: i32 ()* @main, variables: !2)
+!4 = distinct !DISubprogram(name: "main", scope: !1, file: !1, line: 2, type: !5, isLocal: false, isDefinition: true, scopeLine: 3, flags: DIFlagPrototyped, isOptimized: false, variables: !2)
!5 = !DISubroutineType(types: !6)
!6 = !{!7}
!7 = !DIBasicType(name: "int", size: 32, align: 32, encoding: DW_ATE_signed)