[llvm] r264935 - Cloning: Reduce complexity of debug info cloning and fix correctness issue.

[Peter Collingbourne via llvm-commits]

Author: pcc
Date: Wed Mar 30 17:05:13 2016
New Revision: 264935

URL: http://llvm.org/viewvc/llvm-project?rev=264935&view=rev
Log:
Cloning: Reduce complexity of debug info cloning and fix correctness issue.

Commit r260791 contained an error in that it would introduce a cross-module
reference in the old module. It also introduced O(N^2) complexity in the
module cloner by requiring the entire module to be visited for each function.
Fix both of these problems by avoiding use of the CloneDebugInfoMetadata
function (which is only designed to do intra-module cloning) and cloning
function-attached metadata in the same way that we clone all other metadata.

Differential Revision: http://reviews.llvm.org/D18583

Modified:
    llvm/trunk/include/llvm/Transforms/Utils/Cloning.h
    llvm/trunk/lib/Transforms/Utils/CloneFunction.cpp
    llvm/trunk/lib/Transforms/Utils/CloneModule.cpp
    llvm/trunk/unittests/Transforms/Utils/Cloning.cpp

Modified: llvm/trunk/include/llvm/Transforms/Utils/Cloning.h
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/include/llvm/Transforms/Utils/Cloning.h?rev=264935&r1=264934&r2=264935&view=diff
==============================================================================
--- llvm/trunk/include/llvm/Transforms/Utils/Cloning.h (original)
+++ llvm/trunk/include/llvm/Transforms/Utils/Cloning.h Wed Mar 30 17:05:13 2016
@@ -130,11 +130,6 @@ Function *CloneFunction(const Function *
                         bool ModuleLevelChanges,
                         ClonedCodeInfo *CodeInfo = nullptr);
 
-/// Clone the module-level debug info associated with OldFunc. The cloned data
-/// will point to NewFunc instead.
-void CloneDebugInfoMetadata(Function *NewFunc, const Function *OldFunc,
-                            ValueToValueMapTy &VMap);
-
 /// Clone OldFunc into NewFunc, transforming the old arguments into references
 /// to VMap values.  Note that if NewFunc already has basic blocks, the ones
 /// cloned into it will be added to the end of the function.  This function

Modified: llvm/trunk/lib/Transforms/Utils/CloneFunction.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Transforms/Utils/CloneFunction.cpp?rev=264935&r1=264934&r2=264935&view=diff
==============================================================================
--- llvm/trunk/lib/Transforms/Utils/CloneFunction.cpp (original)
+++ llvm/trunk/lib/Transforms/Utils/CloneFunction.cpp Wed Mar 30 17:05:13 2016
@@ -119,6 +119,15 @@ void llvm::CloneFunctionInto(Function *N
           .addAttributes(NewFunc->getContext(), AttributeSet::FunctionIndex,
                          OldAttrs.getFnAttributes()));
 
+  SmallVector<std::pair<unsigned, MDNode *>, 1> MDs;
+  OldFunc->getAllMetadata(MDs);
+  for (auto MD : MDs)
+    NewFunc->setMetadata(
+        MD.first,
+        MapMetadata(MD.second, VMap,
+                    ModuleLevelChanges ? RF_None : RF_NoModuleLevelChanges,
+                    TypeMapper, Materializer));
+
   // Loop over all of the basic blocks in the function, cloning them as
   // appropriate.  Note that we save BE this way in order to handle cloning of
   // recursive functions into themselves.
@@ -187,8 +196,8 @@ static void AddOperand(DICompileUnit *CU
 
 // Clone the module-level debug info associated with OldFunc. The cloned data
 // will point to NewFunc instead.
-void llvm::CloneDebugInfoMetadata(Function *NewFunc, const Function *OldFunc,
-                                  ValueToValueMapTy &VMap) {
+static void CloneDebugInfoMetadata(Function *NewFunc, const Function *OldFunc,
+                                   ValueToValueMapTy &VMap) {
   DebugInfoFinder Finder;
   Finder.processModule(*OldFunc->getParent());
 

Modified: llvm/trunk/lib/Transforms/Utils/CloneModule.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Transforms/Utils/CloneModule.cpp?rev=264935&r1=264934&r2=264935&view=diff
==============================================================================
--- llvm/trunk/lib/Transforms/Utils/CloneModule.cpp (original)
+++ llvm/trunk/lib/Transforms/Utils/CloneModule.cpp Wed Mar 30 17:05:13 2016
@@ -138,7 +138,6 @@ std::unique_ptr<Module> llvm::CloneModul
         VMap[&*J] = &*DestI++;
       }
 
-      CloneDebugInfoMetadata(F, &*I, VMap);
       SmallVector<ReturnInst*, 8> Returns;  // Ignore returns cloned.
       CloneFunctionInto(F, &*I, VMap, /*ModuleLevelChanges=*/true, Returns);
     }

Modified: llvm/trunk/unittests/Transforms/Utils/Cloning.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/unittests/Transforms/Utils/Cloning.cpp?rev=264935&r1=264934&r2=264935&view=diff
==============================================================================
--- llvm/trunk/unittests/Transforms/Utils/Cloning.cpp (original)
+++ llvm/trunk/unittests/Transforms/Utils/Cloning.cpp Wed Mar 30 17:05:13 2016
@@ -464,6 +464,12 @@ TEST_F(CloneModule, Verify) {
   EXPECT_FALSE(verifyModule(*NewM));
 }
 
+TEST_F(CloneModule, OldModuleUnchanged) {
+  DebugInfoFinder Finder;
+  Finder.processModule(*OldM);
+  EXPECT_EQ(1U, Finder.subprogram_count());
+}
+
 TEST_F(CloneModule, Subprogram) {
   Function *NewF = NewM->getFunction("f");
   DISubprogram *SP = NewF->getSubprogram();