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/lib/IR/DebugInfo.cpp b/llvm/lib/IR/DebugInfo.cpp
index b22ba53..a2443be 100644
--- a/llvm/lib/IR/DebugInfo.cpp
+++ b/llvm/lib/IR/DebugInfo.cpp
@@ -300,6 +300,10 @@
bool llvm::stripDebugInfo(Function &F) {
bool Changed = false;
+ if (F.getSubprogram()) {
+ Changed = true;
+ F.setSubprogram(nullptr);
+ }
for (BasicBlock &BB : F) {
for (Instruction &I : BB) {
if (I.getDebugLoc()) {
@@ -359,21 +363,3 @@
return Val->getZExtValue();
return 0;
}
-
-DenseMap<const llvm::Function *, DISubprogram *>
-llvm::makeSubprogramMap(const Module &M) {
- DenseMap<const Function *, DISubprogram *> R;
-
- NamedMDNode *CU_Nodes = M.getNamedMetadata("llvm.dbg.cu");
- if (!CU_Nodes)
- return R;
-
- for (MDNode *N : CU_Nodes->operands()) {
- auto *CUNode = cast<DICompileUnit>(N);
- for (auto *SP : CUNode->getSubprograms()) {
- if (Function *F = SP->getFunction())
- R.insert(std::make_pair(F, SP));
- }
- }
- return R;
-}