[DebugInfo] Unify logic to merge DILocations. NFC.

This makes DILocation::getMergedLocation() do what its comment says it
does when merging locations for an Instruction: set the common inlineAt
scope. This simplifies Instruction::applyMergedLocation() a bit.

Testing: check-llvm, check-clang

Differential Revision: https://reviews.llvm.org/D39628

llvm-svn: 317524

1 files changed, 27 insertions, 0 deletions

diff --git a/llvm/lib/IR/DebugInfoMetadata.cpp b/llvm/lib/IR/DebugInfoMetadata.cpp
index 645bba1652d..0a9c5c19e5a 100644
--- a/llvm/lib/IR/DebugInfoMetadata.cpp
+++ b/llvm/lib/IR/DebugInfoMetadata.cpp
@@ -14,9 +14,11 @@
 #include "llvm/IR/DebugInfoMetadata.h"
 #include "LLVMContextImpl.h"
 #include "MetadataImpl.h"
+#include "llvm/ADT/SmallPtrSet.h"
 #include "llvm/ADT/StringSwitch.h"
 #include "llvm/IR/DIBuilder.h"
 #include "llvm/IR/Function.h"
+#include "llvm/IR/Instructions.h"
 
 using namespace llvm;
 
@@ -66,6 +68,31 @@ DILocation *DILocation::getImpl(LLVMContext &Context, unsigned Line,
                    Storage, Context.pImpl->DILocations);
 }
 
+const DILocation *
+DILocation::getMergedLocation(const DILocation *LocA, const DILocation *LocB,
+                              const Instruction *ForInst) {
+  if (!LocA || !LocB)
+    return nullptr;
+
+  if (LocA == LocB || !LocA->canDiscriminate(*LocB))
+    return LocA;
+
+  if (!dyn_cast_or_null<CallInst>(ForInst))
+    return nullptr;
+
+  SmallPtrSet<DILocation *, 5> InlinedLocationsA;
+  for (DILocation *L = LocA->getInlinedAt(); L; L = L->getInlinedAt())
+    InlinedLocationsA.insert(L);
+  const DILocation *Result = LocB;
+  for (DILocation *L = LocB->getInlinedAt(); L; L = L->getInlinedAt()) {
+    Result = L;
+    if (InlinedLocationsA.count(L))
+      break;
+  }
+  return DILocation::get(Result->getContext(), 0, 0, Result->getScope(),
+                         Result->getInlinedAt());
+}
+
 DINode::DIFlags DINode::getFlag(StringRef Flag) {
   return StringSwitch<DIFlags>(Flag)
 #define HANDLE_DI_FLAG(ID, NAME) .Case("DIFlag" #NAME, Flag##NAME)