Cloning: Clean up the interface to the CloneFunction function.

Remove the ModuleLevelChanges argument, and the ability to create new
subprograms for cloned functions. The latter was added without review in
r203662, but it has no in-tree clients (all non-test callers pass false
for ModuleLevelChanges [1], so it isn't reachable outside of tests). It
also isn't clear that adding a duplicate subprogram to the compile unit is
always the right thing to do when cloning a function within a module. If
this functionality comes back it should be accompanied with a more concrete
use case.

Furthermore, all in-tree clients add the returned function to the module.
Since that's pretty much the only sensible thing you can do with the function,
just do that in CloneFunction.

[1] http://llvm-cs.pcc.me.uk/lib/Transforms/Utils/CloneFunction.cpp/rCloneFunction

Differential Revision: http://reviews.llvm.org/D18628

llvm-svn: 269110

1 files changed, 12 insertions, 28 deletions

diff --git a/llvm/lib/Transforms/Utils/CloneFunction.cpp b/llvm/lib/Transforms/Utils/CloneFunction.cpp
index c8d1212..24f7d69 100644
--- a/llvm/lib/Transforms/Utils/CloneFunction.cpp
+++ b/llvm/lib/Transforms/Utils/CloneFunction.cpp
@@ -172,30 +172,14 @@ void llvm::CloneFunctionInto(Function *NewFunc, const Function *OldFunc,
                        TypeMapper, Materializer);
 }
 
-// Clone the module-level debug info associated with OldFunc. The cloned data
-// will point to NewFunc instead.
-static void CloneDebugInfoMetadata(Function *NewFunc, const Function *OldFunc,
-                                   ValueToValueMapTy &VMap) {
-  if (const DISubprogram *OldSP = OldFunc->getSubprogram()) {
-    auto *NewSP = cast<DISubprogram>(MapMetadata(OldSP, VMap));
-    // FIXME: There ought to be a better way to do this: ValueMapper
-    // will clone the distinct DICompileUnit. Use the original one
-    // instead.
-    NewSP->replaceUnit(OldSP->getUnit());
-    NewFunc->setSubprogram(NewSP);
-  }
-}
-
-/// Return a copy of the specified function, but without
-/// embedding the function into another module.  Also, any references specified
-/// in the VMap are changed to refer to their mapped value instead of the
-/// original one.  If any of the arguments to the function are in the VMap,
-/// the arguments are deleted from the resultant function.  The VMap is
-/// updated to include mappings from all of the instructions and basicblocks in
-/// the function from their old to new values.
+/// Return a copy of the specified function and add it to that function's
+/// module.  Also, any references specified in the VMap are changed to refer to
+/// their mapped value instead of the original one.  If any of the arguments to
+/// the function are in the VMap, the arguments are deleted from the resultant
+/// function.  The VMap is updated to include mappings from all of the
+/// instructions and basicblocks in the function from their old to new values.
 ///
-Function *llvm::CloneFunction(const Function *F, ValueToValueMapTy &VMap,
-                              bool ModuleLevelChanges,
+Function *llvm::CloneFunction(Function *F, ValueToValueMapTy &VMap,
                               ClonedCodeInfo *CodeInfo) {
   std::vector<Type*> ArgTypes;
 
@@ -211,7 +195,8 @@ Function *llvm::CloneFunction(const Function *F, ValueToValueMapTy &VMap,
                                     ArgTypes, F->getFunctionType()->isVarArg());
 
   // Create the new function...
-  Function *NewF = Function::Create(FTy, F->getLinkage(), F->getName());
+  Function *NewF =
+      Function::Create(FTy, F->getLinkage(), F->getName(), F->getParent());
 
   // Loop over the arguments, copying the names of the mapped arguments over...
   Function::arg_iterator DestI = NewF->arg_begin();
@@ -221,11 +206,10 @@ Function *llvm::CloneFunction(const Function *F, ValueToValueMapTy &VMap,
       VMap[&I] = &*DestI++;        // Add mapping to VMap
     }
 
-  if (ModuleLevelChanges)
-    CloneDebugInfoMetadata(NewF, F, VMap);
-
   SmallVector<ReturnInst*, 8> Returns;  // Ignore returns cloned.
-  CloneFunctionInto(NewF, F, VMap, ModuleLevelChanges, Returns, "", CodeInfo);
+  CloneFunctionInto(NewF, F, VMap, /*ModuleLevelChanges=*/false, Returns, "",
+                    CodeInfo);
+
   return NewF;
 }