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/*
* Copyright 2015, The Android Open Source Project
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
#include "Assert.h"
#include "Log.h"
#include "RSUtils.h"
#include "rsDefines.h"
#include <llvm/IR/Constant.h>
#include <llvm/IR/Constants.h>
#include <llvm/IR/Type.h>
#include <llvm/IR/Module.h>
#include <llvm/IR/Function.h>
#include <llvm/Pass.h>
#include <sstream>
#include <vector>
namespace {
const bool kDebugGlobalInfo = false;
/* RSGlobalInfoPass: Embeds additional information about RenderScript global
* variables into the Module. The 5 variables added are specified as follows:
* 1) .rs.global_entries
* i32 - int
* Optional number of global variables.
* 2) .rs.global_names
* [N * i8*] - const char *[N]
* Optional global variable name info. Each entry corresponds to the name
* of 1 of the N global variables.
* 3) .rs.global_addresses
* [N * i8*] - void*[N] or void**
* Optional global variable address info. Each entry corresponds to the
* address of 1 of the N global variables.
* 4) .rs.global_sizes
* [N * i32] or [N * i64] - size_t[N]
* Optional global variable size info. Each entry corresponds to the size
* of 1 of the N global variables.
* 5) .rs.global_properties
* [N * i32]
* Optional global properties. Each entry corresponds to the properties
* for 1 of the N global variables. The 32-bit integer for properties
* can be broken down as follows:
* bit(s) Encoded value
* ------ -------------
* 18 Pointer (1 is pointer, 0 is non-pointer)
* 17 Static (1 is static, 0 is extern)
* 16 Constant (1 is const, 0 is non-const)
* 15 - 0 RsDataType (see frameworks/rs/rsDefines.h for more info)
*/
class RSGlobalInfoPass: public llvm::ModulePass {
private:
// If true, we don't include information about immutable global variables
// in our various exported data structures.
bool mSkipConstants;
// Encodes properties of the GlobalVariable into a uint32_t.
// These values are used to populate the .rs.global_properties array.
static uint32_t getEncodedProperties(const llvm::GlobalVariable &GV) {
auto GlobalType = GV.getType()->getPointerElementType();
// We start by getting the RsDataType and placing it into our result.
uint32_t result = getRsDataTypeForType(GlobalType);
bccAssert(!(result & ~RS_GLOBAL_TYPE)); // Can only alter lower 16-bits.
if (GlobalType->isPointerTy()) {
// Global variables that are pointers can all be used with "bind".
result |= RS_GLOBAL_POINTER;
}
if (GV.isConstant()) {
result |= RS_GLOBAL_CONSTANT;
}
if (GV.getLinkage() == llvm::GlobalValue::InternalLinkage) {
// We only have internal linkage in RS to signify static.
result |= RS_GLOBAL_STATIC;
}
return result;
}
public:
static char ID;
explicit RSGlobalInfoPass(bool pSkipConstants = false)
: ModulePass (ID), mSkipConstants(pSkipConstants) {
}
void getAnalysisUsage(llvm::AnalysisUsage &AU) const override {
// This pass does not use any other analysis passes, but it does
// add new global variables.
}
bool runOnModule(llvm::Module &M) override {
std::vector<llvm::Constant *> GVAddresses;
std::vector<llvm::Constant *> GVNames;
std::vector<std::string> GVNameStrings;
std::vector<uint32_t> GVSizes32;
std::vector<uint64_t> GVSizes64;
std::vector<uint32_t> GVProperties;
const llvm::DataLayout &DL = M.getDataLayout();
const size_t PointerSizeInBits = DL.getPointerSizeInBits();
bccAssert(PointerSizeInBits == 32 || PointerSizeInBits == 64);
int GlobalNumber = 0;
// i8* - LLVM uses this to represent void* and char*
llvm::Type *VoidPtrTy = llvm::Type::getInt8PtrTy(M.getContext());
// i32
llvm::Type *Int32Ty = llvm::Type::getInt32Ty(M.getContext());
// i32 or i64 depending on our actual size_t
llvm::Type *SizeTy = llvm::Type::getIntNTy(M.getContext(),
PointerSizeInBits);
for (auto &GV : M.globals()) {
// Skip constant variables if we were configured to do so.
if (mSkipConstants && GV.isConstant()) {
continue;
}
// Skip intrinsic variables.
if (GV.getName().startswith("llvm.")) {
continue;
}
// In LLVM, an instance of GlobalVariable is actually a Value
// corresponding to the address of it.
GVAddresses.push_back(llvm::ConstantExpr::getBitCast(&GV, VoidPtrTy));
GVNameStrings.push_back(GV.getName());
// Since these are all global variables, their type is actually a
// pointer to the underlying data. We can extract the total underlying
// storage size by looking at the first contained type.
auto GlobalType = GV.getType()->getPointerElementType();
auto TypeSize = DL.getTypeAllocSize(GlobalType);
if (PointerSizeInBits == 32) {
GVSizes32.push_back(TypeSize);
} else {
GVSizes64.push_back(TypeSize);
}
GVProperties.push_back(getEncodedProperties(GV));
}
// Create the new strings for storing the names of the global variables.
// This has to be done as a separate pass (over the original global
// variables), because these strings are new global variables themselves.
for (const auto &GVN : GVNameStrings) {
llvm::Constant *C =
llvm::ConstantDataArray::getString(M.getContext(), GVN);
std::stringstream VarName;
VarName << ".rs.name_str_" << GlobalNumber++;
llvm::Value *V = M.getOrInsertGlobal(VarName.str(), C->getType());
llvm::GlobalVariable *VarAsStr = llvm::dyn_cast<llvm::GlobalVariable>(V);
VarAsStr->setInitializer(C);
VarAsStr->setConstant(true);
VarAsStr->setLinkage(llvm::GlobalValue::PrivateLinkage);
VarAsStr->setUnnamedAddr(llvm::GlobalValue::UnnamedAddr::Global);
// VarAsStr has type [_ x i8]*. Cast to i8* for storing in
// .rs.global_names.
GVNames.push_back(llvm::ConstantExpr::getBitCast(VarAsStr, VoidPtrTy));
}
if (PointerSizeInBits == 32) {
bccAssert(GVAddresses.size() == GVSizes32.size());
bccAssert(GVSizes64.size() == 0);
bccAssert(GVAddresses.size() == GVProperties.size());
} else {
bccAssert(GVSizes32.size() == 0);
bccAssert(GVAddresses.size() == GVSizes64.size());
bccAssert(GVAddresses.size() == GVProperties.size());
}
size_t NumGlobals = GVAddresses.size();
// [NumGlobals * i8*]
llvm::ArrayType *VoidPtrArrayTy = llvm::ArrayType::get(VoidPtrTy,
NumGlobals);
// [NumGlobals * i32] or [NumGlobals * i64]
llvm::ArrayType *SizeArrayTy = llvm::ArrayType::get(SizeTy, NumGlobals);
// [NumGlobals * i32]
llvm::ArrayType *Int32ArrayTy = llvm::ArrayType::get(Int32Ty, NumGlobals);
// 1) @.rs.global_entries = constant i32 NumGlobals
llvm::Value *V = M.getOrInsertGlobal(kRsGlobalEntries, Int32Ty);
llvm::GlobalVariable *GlobalEntries =
llvm::dyn_cast<llvm::GlobalVariable>(V);
llvm::Constant *GlobalEntriesInit =
llvm::ConstantInt::get(Int32Ty, NumGlobals);
GlobalEntries->setInitializer(GlobalEntriesInit);
GlobalEntries->setConstant(true);
// 2) @.rs.global_names = constant [N * i8*] [...]
V = M.getOrInsertGlobal(kRsGlobalNames, VoidPtrArrayTy);
llvm::GlobalVariable *GlobalNames =
llvm::dyn_cast<llvm::GlobalVariable>(V);
llvm::Constant *GlobalNamesInit =
llvm::ConstantArray::get(VoidPtrArrayTy, GVNames);
GlobalNames->setInitializer(GlobalNamesInit);
GlobalNames->setConstant(true);
// 3) @.rs.global_addresses = constant [N * i8*] [...]
V = M.getOrInsertGlobal(kRsGlobalAddresses, VoidPtrArrayTy);
llvm::GlobalVariable *GlobalAddresses =
llvm::dyn_cast<llvm::GlobalVariable>(V);
llvm::Constant *GlobalAddressesInit =
llvm::ConstantArray::get(VoidPtrArrayTy, GVAddresses);
GlobalAddresses->setInitializer(GlobalAddressesInit);
GlobalAddresses->setConstant(true);
// 4) @.rs.global_sizes = constant [N * i32 or i64] [...]
V = M.getOrInsertGlobal(kRsGlobalSizes, SizeArrayTy);
llvm::GlobalVariable *GlobalSizes =
llvm::dyn_cast<llvm::GlobalVariable>(V);
llvm::Constant *GlobalSizesInit;
if (PointerSizeInBits == 32) {
GlobalSizesInit = llvm::ConstantDataArray::get(M.getContext(), GVSizes32);
} else {
GlobalSizesInit = llvm::ConstantDataArray::get(M.getContext(), GVSizes64);
}
GlobalSizes->setInitializer(GlobalSizesInit);
GlobalSizes->setConstant(true);
// 5) @.rs.global_properties = constant i32 NumGlobals
V = M.getOrInsertGlobal(kRsGlobalProperties, Int32ArrayTy);
llvm::GlobalVariable *GlobalProperties =
llvm::dyn_cast<llvm::GlobalVariable>(V);
llvm::Constant *GlobalPropertiesInit =
llvm::ConstantDataArray::get(M.getContext(), GVProperties);
GlobalProperties->setInitializer(GlobalPropertiesInit);
GlobalProperties->setConstant(true);
if (kDebugGlobalInfo) {
GlobalEntries->dump();
GlobalNames->dump();
GlobalAddresses->dump();
GlobalSizes->dump();
GlobalProperties->dump();
}
// Upon completion, this pass has always modified the Module.
return true;
}
};
}
char RSGlobalInfoPass::ID = 0;
static llvm::RegisterPass<RSGlobalInfoPass> X("embed-rs-global-info",
"Embed additional information about RenderScript global variables");
namespace bcc {
llvm::ModulePass * createRSGlobalInfoPass(bool pSkipConstants) {
return new RSGlobalInfoPass(pSkipConstants);
}
}