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

4 files changed, 8 insertions, 8 deletions

diff --git a/llvm/test/CodeGen/PowerPC/dbg.ll b/llvm/test/CodeGen/PowerPC/dbg.ll
index 9b33134babe..b636cff0f20 100644
--- a/llvm/test/CodeGen/PowerPC/dbg.ll
+++ b/llvm/test/CodeGen/PowerPC/dbg.ll
@@ -4,7 +4,7 @@
 target datalayout = "E-p:64:64:64-i1:8:8-i8:8:8-i16:16:16-i32:32:32-i64:64:64-f32:32:32-f64:64:64-v128:128:128-n32:64"
 target triple = "powerpc64-unknown-linux-gnu"
 
-define i32 @main(i32 %argc, i8** nocapture %argv) nounwind readnone {
+define i32 @main(i32 %argc, i8** nocapture %argv) nounwind readnone !dbg !5 {
 entry:
   tail call void @llvm.dbg.value(metadata i32 %argc, i64 0, metadata !15, metadata !DIExpression()), !dbg !17
   tail call void @llvm.dbg.value(metadata i8** %argv, i64 0, metadata !16, metadata !DIExpression()), !dbg !18
@@ -20,7 +20,7 @@ declare void @llvm.dbg.value(metadata, i64, metadata, metadata) nounwind readnon
 !0 = distinct !DICompileUnit(language: DW_LANG_C99, producer: "clang version 3.1", isOptimized: true, emissionKind: 0, file: !21, enums: !1, retainedTypes: !1, subprograms: !3, globals: !1, imports: !1)
 !1 = !{}
 !3 = !{!5}
-!5 = distinct !DISubprogram(name: "main", line: 1, isLocal: false, isDefinition: true, virtualIndex: 6, flags: DIFlagPrototyped, isOptimized: true, file: !21, scope: null, type: !7, function: i32 (i32, i8**)* @main, variables: !13)
+!5 = distinct !DISubprogram(name: "main", line: 1, isLocal: false, isDefinition: true, virtualIndex: 6, flags: DIFlagPrototyped, isOptimized: true, file: !21, scope: null, type: !7, variables: !13)
 !6 = !DIFile(filename: "dbg.c", directory: "/src")
 !7 = !DISubroutineType(types: !8)
 !8 = !{!9, !9, !10}
diff --git a/llvm/test/CodeGen/PowerPC/pr17168.ll b/llvm/test/CodeGen/PowerPC/pr17168.ll
index 41eef12afb8..b1bac59c9ce 100644
--- a/llvm/test/CodeGen/PowerPC/pr17168.ll
+++ b/llvm/test/CodeGen/PowerPC/pr17168.ll
@@ -9,7 +9,7 @@ target triple = "powerpc64-unknown-linux-gnu"
 @grid_points = external global [3 x i32], align 4
 
 ; Function Attrs: nounwind
-define fastcc void @compute_rhs() #0 {
+define fastcc void @compute_rhs() #0 !dbg !114 {
 entry:
   br i1 undef, label %for.cond871.preheader.for.inc960_crit_edge, label %for.end1042, !dbg !439
 
@@ -168,7 +168,7 @@ attributes #1 = { nounwind readnone }
 !111 = !DILocalVariable(name: "d", line: 271, scope: !102, file: !5, type: !8)
 !112 = !DILocalVariable(name: "m", line: 271, scope: !102, file: !5, type: !8)
 !113 = !DILocalVariable(name: "add", line: 272, scope: !102, file: !5, type: !20)
-!114 = distinct !DISubprogram(name: "compute_rhs", line: 1767, isLocal: true, isDefinition: true, virtualIndex: 6, flags: DIFlagPrototyped, isOptimized: true, scopeLine: 1767, file: !1, scope: !5, type: !115, function: void ()* @compute_rhs, variables: !117)
+!114 = distinct !DISubprogram(name: "compute_rhs", line: 1767, isLocal: true, isDefinition: true, virtualIndex: 6, flags: DIFlagPrototyped, isOptimized: true, scopeLine: 1767, file: !1, scope: !5, type: !115, variables: !117)
 !115 = !DISubroutineType(types: !116)
 !116 = !{null}
 !117 = !{!118, !119, !120, !121, !122, !123, !124, !125, !126, !127, !128, !129, !130, !131}
diff --git a/llvm/test/CodeGen/PowerPC/pr24546.ll b/llvm/test/CodeGen/PowerPC/pr24546.ll
index a04edfe65ea..06f6bc93da9 100644
--- a/llvm/test/CodeGen/PowerPC/pr24546.ll
+++ b/llvm/test/CodeGen/PowerPC/pr24546.ll
@@ -6,7 +6,7 @@
 @php_intpow10.powers = external unnamed_addr constant [23 x double], align 8
 
 ; Function Attrs: nounwind
-define double @_php_math_round(double %value, i32 signext %places, i32 signext %mode) #0 {
+define double @_php_math_round(double %value, i32 signext %places, i32 signext %mode) #0 !dbg !6 {
 entry:
   br i1 undef, label %if.then, label %if.else, !dbg !32
 
@@ -62,7 +62,7 @@ attributes #3 = { nounwind }
 !3 = !{!4}
 !4 = !DIBasicType(name: "double", size: 64, align: 64, encoding: DW_ATE_float)
 !5 = !{!6, !18}
-!6 = distinct !DISubprogram(name: "_php_math_round", scope: !1, file: !1, line: 15, type: !7, isLocal: false, isDefinition: true, scopeLine: 16, flags: DIFlagPrototyped, isOptimized: true, function: double (double, i32, i32)* @_php_math_round, variables: !10)
+!6 = distinct !DISubprogram(name: "_php_math_round", scope: !1, file: !1, line: 15, type: !7, isLocal: false, isDefinition: true, scopeLine: 16, flags: DIFlagPrototyped, isOptimized: true, variables: !10)
 !7 = !DISubroutineType(types: !8)
 !8 = !{!4, !4, !9, !9}
 !9 = !DIBasicType(name: "int", size: 32, align: 32, encoding: DW_ATE_signed)
diff --git a/llvm/test/CodeGen/PowerPC/unwind-dw2-g.ll b/llvm/test/CodeGen/PowerPC/unwind-dw2-g.ll
index 69adf2d2052..e44da85f5b3 100644
--- a/llvm/test/CodeGen/PowerPC/unwind-dw2-g.ll
+++ b/llvm/test/CodeGen/PowerPC/unwind-dw2-g.ll
@@ -3,7 +3,7 @@ target datalayout = "E-p:64:64:64-i1:8:8-i8:8:8-i16:16:16-i32:32:32-i64:64:64-f3
 target triple = "powerpc64-unknown-linux-gnu"
 
 ; Function Attrs: nounwind
-define void @foo() #0 {
+define void @foo() #0 !dbg !4 {
 entry:
   call void @llvm.eh.unwind.init(), !dbg !9
   ret void, !dbg !10
@@ -25,7 +25,7 @@ attributes #0 = { nounwind }
 !1 = !DIFile(filename: "/tmp/unwind-dw2.c", directory: "/tmp")
 !2 = !{}
 !3 = !{!4}
-!4 = distinct !DISubprogram(name: "foo", line: 1, isLocal: false, isDefinition: true, virtualIndex: 6, isOptimized: false, scopeLine: 1, file: !1, scope: !5, type: !6, function: void ()* @foo, variables: !2)
+!4 = distinct !DISubprogram(name: "foo", line: 1, isLocal: false, isDefinition: true, virtualIndex: 6, isOptimized: false, scopeLine: 1, file: !1, scope: !5, type: !6, variables: !2)
 !5 = !DIFile(filename: "/tmp/unwind-dw2.c", directory: "/tmp")
 !6 = !DISubroutineType(types: !7)
 !7 = !{null}