[RewriteStatepointsForGC] Fix a bug on creating gc_relocate for pointer to vector of pointers
Summary:
In RewriteStatepointsForGC pass, we create a gc_relocate intrinsic for
each relocated pointer, and the gc_relocate has the same type with the
pointer. During the creation of gc_relocate intrinsic, llvm requires to
mangle its type. However, llvm does not support mangling of all possible
types. RewriteStatepointsForGC will hit an assertion failure when it
tries to create a gc_relocate for pointer to vector of pointers because
mangling for vector of pointers is not supported.
This patch changes the way RewriteStatepointsForGC pass creates
gc_relocate. For each relocated pointer, we erase the type of pointers
and create an unified gc_relocate of type i8 addrspace(1)*. Then a
bitcast is inserted to convert the gc_relocate to the correct type. In
this way, gc_relocate does not need to deal with different types of
pointers and the unsupported type mangling is no longer a problem. This
change would also ease further merge when LLVM erases types of pointers
and introduces an unified pointer type.
Some minor changes are also introduced to gc_relocate related part in
InstCombineCalls, CodeGenPrepare, and Verifier accordingly.
Patch by Chen Li!
Reviewers: reames, AndyAyers, sanjoy
Reviewed By: sanjoy
Subscribers: llvm-commits
Differential Revision: http://reviews.llvm.org/D9592
llvm-svn: 237009
diff --git a/llvm/lib/Transforms/Scalar/RewriteStatepointsForGC.cpp b/llvm/lib/Transforms/Scalar/RewriteStatepointsForGC.cpp
index 9cb0748..7f33295 100644
--- a/llvm/lib/Transforms/Scalar/RewriteStatepointsForGC.cpp
+++ b/llvm/lib/Transforms/Scalar/RewriteStatepointsForGC.cpp
@@ -1075,7 +1075,10 @@
// the IR, but removes the need for argument bitcasts which shrinks the IR
// greatly and makes it much more readable.
SmallVector<Type *, 1> types; // one per 'any' type
- types.push_back(liveVariables[i]->getType()); // result type
+ // All gc_relocate are set to i8 addrspace(1)* type. This could help avoid
+ // cases where the actual value's type mangling is not supported by llvm. A
+ // bitcast is added later to convert gc_relocate to the actual value's type.
+ types.push_back(Type::getInt8PtrTy(M->getContext(), 1));
Value *gc_relocate_decl = Intrinsic::getDeclaration(
M, Intrinsic::experimental_gc_relocate, types);
@@ -1342,8 +1345,16 @@
Value *alloca = allocaMap[originalValue];
// Emit store into the related alloca
- StoreInst *store = new StoreInst(relocatedValue, alloca);
- store->insertAfter(relocatedValue);
+ // All gc_relocate are i8 addrspace(1)* typed, and it must be bitcasted to
+ // the correct type according to alloca.
+ assert(relocatedValue->getNextNode() && "Should always have one since it's not a terminator");
+ IRBuilder<> Builder(relocatedValue->getNextNode());
+ Value *CastedRelocatedValue =
+ Builder.CreateBitCast(relocatedValue, cast<AllocaInst>(alloca)->getAllocatedType(),
+ relocatedValue->hasName() ? relocatedValue->getName() + ".casted" : "");
+
+ StoreInst *store = new StoreInst(CastedRelocatedValue, alloca);
+ store->insertAfter(cast<Instruction>(CastedRelocatedValue));
#ifndef NDEBUG
visitedLiveValues.insert(originalValue);