DebugInfo: Keep track of subprograms who's arguments have been promoted.

Matching behavior with DeadArgumentElimination (and leveraging some
now-common infrastructure), keep track of the function from debug info
metadata if arguments are promoted.

This may produce interesting debug info - since the arguments may be
missing or of different types... but at least backtraces, inlining, etc,
will be correct.

llvm-svn: 212128

1 files changed, 12 insertions, 0 deletions

diff --git a/llvm/lib/Transforms/IPO/ArgumentPromotion.cpp b/llvm/lib/Transforms/IPO/ArgumentPromotion.cpp
index 4618c26bc65..2e89a252a8e 100644
--- a/llvm/lib/Transforms/IPO/ArgumentPromotion.cpp
+++ b/llvm/lib/Transforms/IPO/ArgumentPromotion.cpp
@@ -39,6 +39,7 @@
 #include "llvm/IR/CFG.h"
 #include "llvm/IR/CallSite.h"
 #include "llvm/IR/Constants.h"
+#include "llvm/IR/DebugInfo.h"
 #include "llvm/IR/DerivedTypes.h"
 #include "llvm/IR/Instructions.h"
 #include "llvm/IR/LLVMContext.h"
@@ -80,8 +81,10 @@ namespace {
     CallGraphNode *DoPromotion(Function *F,
                                SmallPtrSet<Argument*, 8> &ArgsToPromote,
                                SmallPtrSet<Argument*, 8> &ByValArgsToTransform);
+    bool doInitialization(CallGraph &CG) override;
     /// The maximum number of elements to expand, or 0 for unlimited.
     unsigned maxElements;
+    DenseMap<Function *, DISubprogram> FunctionDIs;
   };
 }
 
@@ -604,6 +607,10 @@ CallGraphNode *ArgPromotion::DoPromotion(Function *F,
   Function *NF = Function::Create(NFTy, F->getLinkage(), F->getName());
   NF->copyAttributesFrom(F);
 
+  // Patch the pointer to LLVM function in debug info descriptor.
+  auto DI = FunctionDIs.find(F);
+  if (DI != FunctionDIs.end())
+    DI->second.replaceFunction(NF);
   
   DEBUG(dbgs() << "ARG PROMOTION:  Promoting to:" << *NF << "\n"
         << "From: " << *F);
@@ -903,3 +910,8 @@ CallGraphNode *ArgPromotion::DoPromotion(Function *F,
   
   return NF_CGN;
 }
+
+bool ArgPromotion::doInitialization(CallGraph &CG) {
+  FunctionDIs = makeSubprogramMap(CG.getModule());
+  return CallGraphSCCPass::doInitialization(CG);
+}