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//===-- InternalGlobalMapper.cpp - Mapping Info for Internal Globals ------===//
//
// The LLVM Compiler Infrastructure
//
// This file was developed by the LLVM research group and is distributed under
// the University of Illinois Open Source License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
// InternalGlobalMapper is a pass that helps the runtime trace optimizer map
// the names of internal GlobalValues (which may have mangled,
// unreconstructible names in the executable) to pointers. If the name mangler
// is changed at some point in the future to allow its results to be
// reconstructible (for instance, by making the type mangling symbolic instead
// of using a UniqueID) this pass should probably be phased out.
//
//===----------------------------------------------------------------------===//
#include "llvm/Constants.h"
#include "llvm/Module.h"
#include "llvm/Pass.h"
#include "llvm/Type.h"
#include "llvm/DerivedTypes.h"
using namespace llvm;
namespace llvm {
typedef std::vector<Constant *> GVVectorTy;
class InternalGlobalMapper : public ModulePass {
public:
bool runOnModule(Module &M);
};
ModulePass *llvm::createInternalGlobalMapperPass() {
return new InternalGlobalMapper();
}
static void maybeAddInternalValueToVector (GVVectorTy &Vector, GlobalValue &GV){
// If it's a GlobalValue with internal linkage and a name (i.e. it's going to
// be mangled), then put the GV, casted to sbyte*, in the vector. Otherwise
// add a null.
if (GV.hasInternalLinkage () && GV.hasName ())
Vector.push_back(ConstantExpr::getCast(&GV,
PointerType::get(Type::SByteTy)));
else
Vector.push_back (ConstantPointerNull::get (PointerType::get
(Type::SByteTy)));
}
bool InternalGlobalMapper::runOnModule(Module &M) {
GVVectorTy gvvector;
// Populate the vector with internal global values and their names.
for (Module::giterator i = M.gbegin (), e = M.gend (); i != e; ++i)
maybeAddInternalValueToVector (gvvector, *i);
// Add an extra global for _llvm_internalGlobals itself (null,
// because it's not internal)
gvvector.push_back (ConstantPointerNull::get
(PointerType::get (Type::SByteTy)));
for (Module::iterator i = M.begin (), e = M.end (); i != e; ++i)
maybeAddInternalValueToVector (gvvector, *i);
// Convert the vector to a constant struct of type {Size, [Size x sbyte*]}.
ArrayType *ATy = ArrayType::get (PointerType::get (Type::SByteTy),
gvvector.size ());
std::vector<const Type *> FieldTypes;
FieldTypes.push_back (Type::UIntTy);
FieldTypes.push_back (ATy);
StructType *STy = StructType::get (FieldTypes);
std::vector<Constant *> FieldValues;
FieldValues.push_back (ConstantUInt::get (Type::UIntTy, gvvector.size ()));
FieldValues.push_back (ConstantArray::get (ATy, gvvector));
// Add the constant struct to M as an external global symbol named
// "_llvm_internalGlobals".
new GlobalVariable (STy, true, GlobalValue::ExternalLinkage,
ConstantStruct::get (STy, FieldValues),
"_llvm_internalGlobals", &M);
return true; // Module was modified.
}
} // end namespace llvm
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