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/*
* Copyright 2012, 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 "bcc/Assert.h"
#include "bcc/Renderscript/RSTransforms.h"
#include <cstdlib>
#include <functional>
#include <llvm/IR/DerivedTypes.h>
#include <llvm/IR/Function.h>
#include <llvm/IR/Instructions.h>
#include <llvm/IR/IRBuilder.h>
#include <llvm/IR/MDBuilder.h>
#include <llvm/IR/Module.h>
#include <llvm/Pass.h>
#include <llvm/Support/raw_ostream.h>
#include <llvm/IR/DataLayout.h>
#include <llvm/IR/Function.h>
#include <llvm/IR/Type.h>
#include <llvm/Transforms/Utils/BasicBlockUtils.h>
#include "bcc/Config/Config.h"
#include "bcc/Support/Log.h"
#include "bcinfo/MetadataExtractor.h"
#define NUM_EXPANDED_FUNCTION_PARAMS 4
using namespace bcc;
namespace {
static const bool gEnableRsTbaa = true;
/* RSForEachExpandPass - This pass operates on functions that are able to be
* called via rsForEach() or "foreach_<NAME>". We create an inner loop for the
* ForEach-able function to be invoked over the appropriate data cells of the
* input/output allocations (adjusting other relevant parameters as we go). We
* support doing this for any ForEach-able compute kernels. The new function
* name is the original function name followed by ".expand". Note that we
* still generate code for the original function.
*/
class RSForEachExpandPass : public llvm::ModulePass {
public:
static char ID;
private:
static const size_t RS_KERNEL_INPUT_LIMIT = 8; // see frameworks/base/libs/rs/cpu_ref/rsCpuCoreRuntime.h
enum RsLaunchDimensionsField {
RsLaunchDimensionsFieldX,
RsLaunchDimensionsFieldY,
RsLaunchDimensionsFieldZ,
RsLaunchDimensionsFieldLod,
RsLaunchDimensionsFieldFace,
RsLaunchDimensionsFieldArray,
RsLaunchDimensionsFieldCount
};
enum RsExpandKernelDriverInfoPfxField {
RsExpandKernelDriverInfoPfxFieldInPtr,
RsExpandKernelDriverInfoPfxFieldInStride,
RsExpandKernelDriverInfoPfxFieldInLen,
RsExpandKernelDriverInfoPfxFieldOutPtr,
RsExpandKernelDriverInfoPfxFieldOutStride,
RsExpandKernelDriverInfoPfxFieldOutLen,
RsExpandKernelDriverInfoPfxFieldDim,
RsExpandKernelDriverInfoPfxFieldCurrent,
RsExpandKernelDriverInfoPfxFieldUsr,
RsExpandKernelDriverInfoPfxFieldUsLenr,
RsExpandKernelDriverInfoPfxFieldCount
};
llvm::Module *Module;
llvm::LLVMContext *Context;
/*
* Pointer to LLVM type information for the the function signature
* for expanded kernels. This must be re-calculated for each
* module the pass is run on.
*/
llvm::FunctionType *ExpandedFunctionType;
uint32_t mExportForEachCount;
const char **mExportForEachNameList;
const uint32_t *mExportForEachSignatureList;
// Turns on optimization of allocation stride values.
bool mEnableStepOpt;
uint32_t getRootSignature(llvm::Function *Function) {
const llvm::NamedMDNode *ExportForEachMetadata =
Module->getNamedMetadata("#rs_export_foreach");
if (!ExportForEachMetadata) {
llvm::SmallVector<llvm::Type*, 8> RootArgTys;
for (llvm::Function::arg_iterator B = Function->arg_begin(),
E = Function->arg_end();
B != E;
++B) {
RootArgTys.push_back(B->getType());
}
// For pre-ICS bitcode, we may not have signature information. In that
// case, we use the size of the RootArgTys to select the number of
// arguments.
return (1 << RootArgTys.size()) - 1;
}
if (ExportForEachMetadata->getNumOperands() == 0) {
return 0;
}
bccAssert(ExportForEachMetadata->getNumOperands() > 0);
// We only handle the case for legacy root() functions here, so this is
// hard-coded to look at only the first such function.
llvm::MDNode *SigNode = ExportForEachMetadata->getOperand(0);
if (SigNode != nullptr && SigNode->getNumOperands() == 1) {
llvm::Metadata *SigMD = SigNode->getOperand(0);
if (llvm::MDString *SigS = llvm::dyn_cast<llvm::MDString>(SigMD)) {
llvm::StringRef SigString = SigS->getString();
uint32_t Signature = 0;
if (SigString.getAsInteger(10, Signature)) {
ALOGE("Non-integer signature value '%s'", SigString.str().c_str());
return 0;
}
return Signature;
}
}
return 0;
}
bool isStepOptSupported(llvm::Type *AllocType) {
llvm::PointerType *PT = llvm::dyn_cast<llvm::PointerType>(AllocType);
llvm::Type *VoidPtrTy = llvm::Type::getInt8PtrTy(*Context);
if (mEnableStepOpt) {
return false;
}
if (AllocType == VoidPtrTy) {
return false;
}
if (!PT) {
return false;
}
// remaining conditions are 64-bit only
if (VoidPtrTy->getPrimitiveSizeInBits() == 32) {
return true;
}
// coerce suggests an upconverted struct type, which we can't support
if (AllocType->getStructName().find("coerce") != llvm::StringRef::npos) {
return false;
}
// 2xi64 and i128 suggest an upconverted struct type, which are also unsupported
llvm::Type *V2xi64Ty = llvm::VectorType::get(llvm::Type::getInt64Ty(*Context), 2);
llvm::Type *Int128Ty = llvm::Type::getIntNTy(*Context, 128);
if (AllocType == V2xi64Ty || AllocType == Int128Ty) {
return false;
}
return true;
}
// Get the actual value we should use to step through an allocation.
//
// Normally the value we use to step through an allocation is given to us by
// the driver. However, for certain primitive data types, we can derive an
// integer constant for the step value. We use this integer constant whenever
// possible to allow further compiler optimizations to take place.
//
// DL - Target Data size/layout information.
// T - Type of allocation (should be a pointer).
// OrigStep - Original step increment (root.expand() input from driver).
llvm::Value *getStepValue(llvm::DataLayout *DL, llvm::Type *AllocType,
llvm::Value *OrigStep) {
bccAssert(DL);
bccAssert(AllocType);
bccAssert(OrigStep);
llvm::PointerType *PT = llvm::dyn_cast<llvm::PointerType>(AllocType);
if (isStepOptSupported(AllocType)) {
llvm::Type *ET = PT->getElementType();
uint64_t ETSize = DL->getTypeAllocSize(ET);
llvm::Type *Int32Ty = llvm::Type::getInt32Ty(*Context);
return llvm::ConstantInt::get(Int32Ty, ETSize);
} else {
return OrigStep;
}
}
/// Builds the types required by the pass for the given context.
void buildTypes(void) {
// Create the RsLaunchDimensionsTy and RsExpandKernelDriverInfoPfxTy structs.
llvm::Type *Int8Ty = llvm::Type::getInt8Ty(*Context);
llvm::Type *Int8PtrTy = Int8Ty->getPointerTo();
llvm::Type *Int8PtrArrayInputLimitTy = llvm::ArrayType::get(Int8PtrTy, RS_KERNEL_INPUT_LIMIT);
llvm::Type *Int32Ty = llvm::Type::getInt32Ty(*Context);
llvm::Type *Int32ArrayInputLimitTy = llvm::ArrayType::get(Int32Ty, RS_KERNEL_INPUT_LIMIT);
llvm::Type *VoidPtrTy = llvm::Type::getInt8PtrTy(*Context);
llvm::Type *Int32Array4Ty = llvm::ArrayType::get(Int32Ty, 4);
/* Defined in frameworks/base/libs/rs/cpu_ref/rsCpuCore.h:
*
* struct RsLaunchDimensions {
* uint32_t x;
* uint32_t y;
* uint32_t z;
* uint32_t lod;
* uint32_t face;
* uint32_t array[4];
* };
*/
llvm::SmallVector<llvm::Type*, RsLaunchDimensionsFieldCount> RsLaunchDimensionsTypes;
RsLaunchDimensionsTypes.push_back(Int32Ty); // uint32_t x
RsLaunchDimensionsTypes.push_back(Int32Ty); // uint32_t y
RsLaunchDimensionsTypes.push_back(Int32Ty); // uint32_t z
RsLaunchDimensionsTypes.push_back(Int32Ty); // uint32_t lod
RsLaunchDimensionsTypes.push_back(Int32Ty); // uint32_t face
RsLaunchDimensionsTypes.push_back(Int32Array4Ty); // uint32_t array[4]
llvm::StructType *RsLaunchDimensionsTy =
llvm::StructType::create(RsLaunchDimensionsTypes, "RsLaunchDimensions");
/* Defined as the beginning of RsExpandKernelDriverInfo in frameworks/base/libs/rs/cpu_ref/rsCpuCoreRuntime.h:
*
* struct RsExpandKernelDriverInfoPfx {
* const uint8_t *inPtr[RS_KERNEL_INPUT_LIMIT];
* uint32_t inStride[RS_KERNEL_INPUT_LIMIT];
* uint32_t inLen;
*
* uint8_t *outPtr[RS_KERNEL_INPUT_LIMIT];
* uint32_t outStride[RS_KERNEL_INPUT_LIMIT];
* uint32_t outLen;
*
* // Dimension of the launch
* RsLaunchDimensions dim;
*
* // The walking iterator of the launch
* RsLaunchDimensions current;
*
* const void *usr;
* uint32_t usrLen;
*
* // Items below this line are not used by the compiler and can be change in the driver.
* // So the compiler must assume there are an unknown number of fields of unknown type
* // beginning here.
* };
*
* The name "RsExpandKernelDriverInfoPfx" is known to RSInvariantPass (RSInvariant.cpp).
*/
llvm::SmallVector<llvm::Type*, RsExpandKernelDriverInfoPfxFieldCount> RsExpandKernelDriverInfoPfxTypes;
RsExpandKernelDriverInfoPfxTypes.push_back(Int8PtrArrayInputLimitTy); // const uint8_t *inPtr[RS_KERNEL_INPUT_LIMIT]
RsExpandKernelDriverInfoPfxTypes.push_back(Int32ArrayInputLimitTy); // uint32_t inStride[RS_KERNEL_INPUT_LIMIT]
RsExpandKernelDriverInfoPfxTypes.push_back(Int32Ty); // uint32_t inLen
RsExpandKernelDriverInfoPfxTypes.push_back(Int8PtrArrayInputLimitTy); // uint8_t *outPtr[RS_KERNEL_INPUT_LIMIT]
RsExpandKernelDriverInfoPfxTypes.push_back(Int32ArrayInputLimitTy); // uint32_t outStride[RS_KERNEL_INPUT_LIMIT]
RsExpandKernelDriverInfoPfxTypes.push_back(Int32Ty); // uint32_t outLen
RsExpandKernelDriverInfoPfxTypes.push_back(RsLaunchDimensionsTy); // RsLaunchDimensions dim
RsExpandKernelDriverInfoPfxTypes.push_back(RsLaunchDimensionsTy); // RsLaunchDimensions current
RsExpandKernelDriverInfoPfxTypes.push_back(VoidPtrTy); // const void *usr
RsExpandKernelDriverInfoPfxTypes.push_back(Int32Ty); // uint32_t usrLen
llvm::StructType *RsExpandKernelDriverInfoPfxTy =
llvm::StructType::create(RsExpandKernelDriverInfoPfxTypes, "RsExpandKernelDriverInfoPfx");
// Create the function type for expanded kernels.
llvm::Type *RsExpandKernelDriverInfoPfxPtrTy = RsExpandKernelDriverInfoPfxTy->getPointerTo();
llvm::SmallVector<llvm::Type*, 8> ParamTypes;
ParamTypes.push_back(RsExpandKernelDriverInfoPfxPtrTy); // const RsExpandKernelDriverInfoPfx *p
ParamTypes.push_back(Int32Ty); // uint32_t x1
ParamTypes.push_back(Int32Ty); // uint32_t x2
ParamTypes.push_back(Int32Ty); // uint32_t outstep
ExpandedFunctionType =
llvm::FunctionType::get(llvm::Type::getVoidTy(*Context), ParamTypes,
false);
}
/// @brief Create skeleton of the expanded function.
///
/// This creates a function with the following signature:
///
/// void (const RsForEachStubParamStruct *p, uint32_t x1, uint32_t x2,
/// uint32_t outstep)
///
llvm::Function *createEmptyExpandedFunction(llvm::StringRef OldName) {
llvm::Function *ExpandedFunction =
llvm::Function::Create(ExpandedFunctionType,
llvm::GlobalValue::ExternalLinkage,
OldName + ".expand", Module);
bccAssert(ExpandedFunction->arg_size() == NUM_EXPANDED_FUNCTION_PARAMS);
llvm::Function::arg_iterator AI = ExpandedFunction->arg_begin();
(AI++)->setName("p");
(AI++)->setName("x1");
(AI++)->setName("x2");
(AI++)->setName("arg_outstep");
llvm::BasicBlock *Begin = llvm::BasicBlock::Create(*Context, "Begin",
ExpandedFunction);
llvm::IRBuilder<> Builder(Begin);
Builder.CreateRetVoid();
return ExpandedFunction;
}
/// @brief Create an empty loop
///
/// Create a loop of the form:
///
/// for (i = LowerBound; i < UpperBound; i++)
/// ;
///
/// After the loop has been created, the builder is set such that
/// instructions can be added to the loop body.
///
/// @param Builder The builder to use to build this loop. The current
/// position of the builder is the position the loop
/// will be inserted.
/// @param LowerBound The first value of the loop iterator
/// @param UpperBound The maximal value of the loop iterator
/// @param LoopIV A reference that will be set to the loop iterator.
/// @return The BasicBlock that will be executed after the loop.
llvm::BasicBlock *createLoop(llvm::IRBuilder<> &Builder,
llvm::Value *LowerBound,
llvm::Value *UpperBound,
llvm::PHINode **LoopIV) {
bccAssert(LowerBound->getType() == UpperBound->getType());
llvm::BasicBlock *CondBB, *AfterBB, *HeaderBB;
llvm::Value *Cond, *IVNext;
llvm::PHINode *IV;
CondBB = Builder.GetInsertBlock();
AfterBB = llvm::SplitBlock(CondBB, Builder.GetInsertPoint(), nullptr, nullptr);
HeaderBB = llvm::BasicBlock::Create(*Context, "Loop", CondBB->getParent());
// if (LowerBound < Upperbound)
// goto LoopHeader
// else
// goto AfterBB
CondBB->getTerminator()->eraseFromParent();
Builder.SetInsertPoint(CondBB);
Cond = Builder.CreateICmpULT(LowerBound, UpperBound);
Builder.CreateCondBr(Cond, HeaderBB, AfterBB);
// iv = PHI [CondBB -> LowerBound], [LoopHeader -> NextIV ]
// iv.next = iv + 1
// if (iv.next < Upperbound)
// goto LoopHeader
// else
// goto AfterBB
Builder.SetInsertPoint(HeaderBB);
IV = Builder.CreatePHI(LowerBound->getType(), 2, "X");
IV->addIncoming(LowerBound, CondBB);
IVNext = Builder.CreateNUWAdd(IV, Builder.getInt32(1));
IV->addIncoming(IVNext, HeaderBB);
Cond = Builder.CreateICmpULT(IVNext, UpperBound);
Builder.CreateCondBr(Cond, HeaderBB, AfterBB);
AfterBB->setName("Exit");
Builder.SetInsertPoint(HeaderBB->getFirstNonPHI());
*LoopIV = IV;
return AfterBB;
}
public:
RSForEachExpandPass(bool pEnableStepOpt = true)
: ModulePass(ID), Module(nullptr), Context(nullptr),
mEnableStepOpt(pEnableStepOpt) {
}
virtual void getAnalysisUsage(llvm::AnalysisUsage &AU) const override {
// This pass does not use any other analysis passes, but it does
// add/wrap the existing functions in the module (thus altering the CFG).
}
// Build contribution to outgoing argument list for calling a
// ForEach-able function, based on the special parameters of that
// function.
//
// Signature - metadata bits for the signature of the ForEach-able function
// X, Arg_p - values derived directly from expanded function,
// suitable for computing arguments for the ForEach-able function
// CalleeArgs - contribution is accumulated here
// Bump - invoked once for each contributed outgoing argument
void ExpandSpecialArguments(uint32_t Signature,
llvm::Value *X,
llvm::Value *Arg_p,
llvm::IRBuilder<> &Builder,
llvm::SmallVector<llvm::Value*, 8> &CalleeArgs,
std::function<void ()> Bump) {
if (bcinfo::MetadataExtractor::hasForEachSignatureCtxt(Signature)) {
CalleeArgs.push_back(Arg_p);
Bump();
}
if (bcinfo::MetadataExtractor::hasForEachSignatureX(Signature)) {
CalleeArgs.push_back(X);
Bump();
}
if (bcinfo::MetadataExtractor::hasForEachSignatureY(Signature) ||
bcinfo::MetadataExtractor::hasForEachSignatureZ(Signature)) {
llvm::Value *Current = Builder.CreateStructGEP(nullptr, Arg_p, RsExpandKernelDriverInfoPfxFieldCurrent);
if (bcinfo::MetadataExtractor::hasForEachSignatureY(Signature)) {
llvm::Value *Y = Builder.CreateLoad(
Builder.CreateStructGEP(nullptr, Current, RsLaunchDimensionsFieldY), "Y");
CalleeArgs.push_back(Y);
Bump();
}
if (bcinfo::MetadataExtractor::hasForEachSignatureZ(Signature)) {
llvm::Value *Z = Builder.CreateLoad(
Builder.CreateStructGEP(nullptr, Current, RsLaunchDimensionsFieldZ), "Z");
CalleeArgs.push_back(Z);
Bump();
}
}
}
/* Performs the actual optimization on a selected function. On success, the
* Module will contain a new function of the name "<NAME>.expand" that
* invokes <NAME>() in a loop with the appropriate parameters.
*/
bool ExpandFunction(llvm::Function *Function, uint32_t Signature) {
ALOGV("Expanding ForEach-able Function %s",
Function->getName().str().c_str());
if (!Signature) {
Signature = getRootSignature(Function);
if (!Signature) {
// We couldn't determine how to expand this function based on its
// function signature.
return false;
}
}
llvm::DataLayout DL(Module);
llvm::Function *ExpandedFunction =
createEmptyExpandedFunction(Function->getName());
/*
* Extract the expanded function's parameters. It is guaranteed by
* createEmptyExpandedFunction that there will be five parameters.
*/
bccAssert(ExpandedFunction->arg_size() == NUM_EXPANDED_FUNCTION_PARAMS);
llvm::Function::arg_iterator ExpandedFunctionArgIter =
ExpandedFunction->arg_begin();
llvm::Value *Arg_p = &*(ExpandedFunctionArgIter++);
llvm::Value *Arg_x1 = &*(ExpandedFunctionArgIter++);
llvm::Value *Arg_x2 = &*(ExpandedFunctionArgIter++);
llvm::Value *Arg_outstep = &*(ExpandedFunctionArgIter);
llvm::Value *InStep = nullptr;
llvm::Value *OutStep = nullptr;
// Construct the actual function body.
llvm::IRBuilder<> Builder(ExpandedFunction->getEntryBlock().begin());
// Collect and construct the arguments for the kernel().
// Note that we load any loop-invariant arguments before entering the Loop.
llvm::Function::arg_iterator FunctionArgIter = Function->arg_begin();
llvm::Type *InTy = nullptr;
llvm::Value *InBasePtr = nullptr;
if (bcinfo::MetadataExtractor::hasForEachSignatureIn(Signature)) {
llvm::Value *InsBasePtr = Builder.CreateStructGEP(nullptr, Arg_p, RsExpandKernelDriverInfoPfxFieldInPtr, "inputs_base");
llvm::Value *InStepsBase = Builder.CreateStructGEP(nullptr, Arg_p, RsExpandKernelDriverInfoPfxFieldInStride, "insteps_base");
llvm::Value *InStepAddr = Builder.CreateConstInBoundsGEP2_32(nullptr, InStepsBase, 0, 0);
llvm::LoadInst *InStepArg = Builder.CreateLoad(InStepAddr,
"instep_addr");
InTy = (FunctionArgIter++)->getType();
InStep = getStepValue(&DL, InTy, InStepArg);
InStep->setName("instep");
llvm::Value *InputAddr = Builder.CreateConstInBoundsGEP2_32(nullptr, InsBasePtr, 0, 0);
InBasePtr = Builder.CreateLoad(InputAddr, "input_base");
}
llvm::Type *OutTy = nullptr;
llvm::Value *OutBasePtr = nullptr;
if (bcinfo::MetadataExtractor::hasForEachSignatureOut(Signature)) {
OutTy = (FunctionArgIter++)->getType();
OutStep = getStepValue(&DL, OutTy, Arg_outstep);
OutStep->setName("outstep");
OutBasePtr = Builder.CreateLoad(
Builder.CreateConstInBoundsGEP2_32(nullptr,
Builder.CreateStructGEP(nullptr, Arg_p, RsExpandKernelDriverInfoPfxFieldOutPtr),
0, 0));
}
llvm::Value *UsrData = nullptr;
if (bcinfo::MetadataExtractor::hasForEachSignatureUsrData(Signature)) {
llvm::Type *UsrDataTy = (FunctionArgIter++)->getType();
UsrData = Builder.CreatePointerCast(Builder.CreateLoad(
Builder.CreateStructGEP(nullptr, Arg_p, RsExpandKernelDriverInfoPfxFieldUsr)), UsrDataTy);
UsrData->setName("UsrData");
}
llvm::PHINode *IV;
createLoop(Builder, Arg_x1, Arg_x2, &IV);
llvm::SmallVector<llvm::Value*, 8> CalleeArgs;
ExpandSpecialArguments(Signature, IV, Arg_p, Builder, CalleeArgs,
[&FunctionArgIter]() { FunctionArgIter++; });
bccAssert(FunctionArgIter == Function->arg_end());
// Populate the actual call to kernel().
llvm::SmallVector<llvm::Value*, 8> RootArgs;
llvm::Value *InPtr = nullptr;
llvm::Value *OutPtr = nullptr;
// Calculate the current input and output pointers
//
// We always calculate the input/output pointers with a GEP operating on i8
// values and only cast at the very end to OutTy. This is because the step
// between two values is given in bytes.
//
// TODO: We could further optimize the output by using a GEP operation of
// type 'OutTy' in cases where the element type of the allocation allows.
if (OutBasePtr) {
llvm::Value *OutOffset = Builder.CreateSub(IV, Arg_x1);
OutOffset = Builder.CreateMul(OutOffset, OutStep);
OutPtr = Builder.CreateGEP(OutBasePtr, OutOffset);
OutPtr = Builder.CreatePointerCast(OutPtr, OutTy);
}
if (InBasePtr) {
llvm::Value *InOffset = Builder.CreateSub(IV, Arg_x1);
InOffset = Builder.CreateMul(InOffset, InStep);
InPtr = Builder.CreateGEP(InBasePtr, InOffset);
InPtr = Builder.CreatePointerCast(InPtr, InTy);
}
if (InPtr) {
RootArgs.push_back(InPtr);
}
if (OutPtr) {
RootArgs.push_back(OutPtr);
}
if (UsrData) {
RootArgs.push_back(UsrData);
}
RootArgs.append(CalleeArgs.begin(), CalleeArgs.end());
Builder.CreateCall(Function, RootArgs);
return true;
}
/* Expand a pass-by-value kernel.
*/
bool ExpandKernel(llvm::Function *Function, uint32_t Signature) {
bccAssert(bcinfo::MetadataExtractor::hasForEachSignatureKernel(Signature));
ALOGV("Expanding kernel Function %s", Function->getName().str().c_str());
// TODO: Refactor this to share functionality with ExpandFunction.
llvm::DataLayout DL(Module);
llvm::Function *ExpandedFunction =
createEmptyExpandedFunction(Function->getName());
/*
* Extract the expanded function's parameters. It is guaranteed by
* createEmptyExpandedFunction that there will be five parameters.
*/
bccAssert(ExpandedFunction->arg_size() == NUM_EXPANDED_FUNCTION_PARAMS);
llvm::Function::arg_iterator ExpandedFunctionArgIter =
ExpandedFunction->arg_begin();
llvm::Value *Arg_p = &*(ExpandedFunctionArgIter++);
llvm::Value *Arg_x1 = &*(ExpandedFunctionArgIter++);
llvm::Value *Arg_x2 = &*(ExpandedFunctionArgIter++);
llvm::Value *Arg_outstep = &*(ExpandedFunctionArgIter);
// Construct the actual function body.
llvm::IRBuilder<> Builder(ExpandedFunction->getEntryBlock().begin());
// Create TBAA meta-data.
llvm::MDNode *TBAARenderScriptDistinct, *TBAARenderScript,
*TBAAAllocation, *TBAAPointer;
llvm::MDBuilder MDHelper(*Context);
TBAARenderScriptDistinct =
MDHelper.createTBAARoot("RenderScript Distinct TBAA");
TBAARenderScript = MDHelper.createTBAANode("RenderScript TBAA",
TBAARenderScriptDistinct);
TBAAAllocation = MDHelper.createTBAAScalarTypeNode("allocation",
TBAARenderScript);
TBAAAllocation = MDHelper.createTBAAStructTagNode(TBAAAllocation,
TBAAAllocation, 0);
TBAAPointer = MDHelper.createTBAAScalarTypeNode("pointer",
TBAARenderScript);
TBAAPointer = MDHelper.createTBAAStructTagNode(TBAAPointer, TBAAPointer, 0);
llvm::MDNode *AliasingDomain, *AliasingScope;
AliasingDomain = MDHelper.createAnonymousAliasScopeDomain("RS argument scope domain");
AliasingScope = MDHelper.createAnonymousAliasScope(AliasingDomain, "RS argument scope");
/*
* Collect and construct the arguments for the kernel().
*
* Note that we load any loop-invariant arguments before entering the Loop.
*/
size_t NumInputs = Function->arg_size();
// No usrData parameter on kernels.
bccAssert(
!bcinfo::MetadataExtractor::hasForEachSignatureUsrData(Signature));
llvm::Function::arg_iterator ArgIter = Function->arg_begin();
// Check the return type
llvm::Type *OutTy = nullptr;
llvm::Value *OutStep = nullptr;
llvm::LoadInst *OutBasePtr = nullptr;
llvm::Value *CastedOutBasePtr = nullptr;
bool PassOutByPointer = false;
if (bcinfo::MetadataExtractor::hasForEachSignatureOut(Signature)) {
llvm::Type *OutBaseTy = Function->getReturnType();
if (OutBaseTy->isVoidTy()) {
PassOutByPointer = true;
OutTy = ArgIter->getType();
ArgIter++;
--NumInputs;
} else {
// We don't increment Args, since we are using the actual return type.
OutTy = OutBaseTy->getPointerTo();
}
OutStep = getStepValue(&DL, OutTy, Arg_outstep);
OutStep->setName("outstep");
OutBasePtr = Builder.CreateLoad(
Builder.CreateConstInBoundsGEP2_32(nullptr,
Builder.CreateStructGEP(nullptr, Arg_p, RsExpandKernelDriverInfoPfxFieldOutPtr),
0, 0));
if (gEnableRsTbaa) {
OutBasePtr->setMetadata("tbaa", TBAAPointer);
}
OutBasePtr->setMetadata("alias.scope", AliasingScope);
CastedOutBasePtr = Builder.CreatePointerCast(OutBasePtr, OutTy, "casted_out");
}
llvm::PHINode *IV;
createLoop(Builder, Arg_x1, Arg_x2, &IV);
llvm::SmallVector<llvm::Value*, 8> CalleeArgs;
ExpandSpecialArguments(Signature, IV, Arg_p, Builder, CalleeArgs,
[&NumInputs]() { --NumInputs; });
llvm::SmallVector<llvm::Type*, 8> InTypes;
llvm::SmallVector<llvm::Value*, 8> InSteps;
llvm::SmallVector<llvm::Value*, 8> InBasePtrs;
llvm::SmallVector<bool, 8> InIsStructPointer;
bccAssert(NumInputs <= RS_KERNEL_INPUT_LIMIT);
if (NumInputs > 0) {
llvm::Value *InsBasePtr = Builder.CreateStructGEP(nullptr, Arg_p, RsExpandKernelDriverInfoPfxFieldInPtr, "inputs_base");
llvm::Value *InStepsBase = Builder.CreateStructGEP(nullptr, Arg_p, RsExpandKernelDriverInfoPfxFieldInStride, "insteps_base");
for (size_t InputIndex = 0; InputIndex < NumInputs;
++InputIndex, ArgIter++) {
llvm::Value *InStepAddr = Builder.CreateConstInBoundsGEP2_32(nullptr, InStepsBase, 0, InputIndex);
llvm::LoadInst *InStepArg = Builder.CreateLoad(InStepAddr,
"instep_addr");
llvm::Type *InType = ArgIter->getType();
/*
* AArch64 calling dictate that structs of sufficient size get passed by
* pointer instead of passed by value. This, combined with the fact
* that we don't allow kernels to operate on pointer data means that if
* we see a kernel with a pointer parameter we know that it is struct
* input that has been promoted. As such we don't need to convert its
* type to a pointer. Later we will need to know to avoid a load, so we
* save this information in InIsStructPointer.
*/
if (!InType->isPointerTy()) {
InType = InType->getPointerTo();
InIsStructPointer.push_back(false);
} else {
InIsStructPointer.push_back(true);
}
llvm::Value *InStep = getStepValue(&DL, InType, InStepArg);
InStep->setName("instep");
llvm::Value *InputAddr = Builder.CreateConstInBoundsGEP2_32(nullptr, InsBasePtr, 0, InputIndex);
llvm::LoadInst *InBasePtr = Builder.CreateLoad(InputAddr,
"input_base");
llvm::Value *CastInBasePtr = Builder.CreatePointerCast(InBasePtr,
InType, "casted_in");
if (gEnableRsTbaa) {
InBasePtr->setMetadata("tbaa", TBAAPointer);
}
InBasePtr->setMetadata("alias.scope", AliasingScope);
InTypes.push_back(InType);
InSteps.push_back(InStep);
InBasePtrs.push_back(CastInBasePtr);
}
}
// Populate the actual call to kernel().
llvm::SmallVector<llvm::Value*, 8> RootArgs;
// Calculate the current input and output pointers
//
//
// We always calculate the input/output pointers with a GEP operating on i8
// values combined with a multiplication and only cast at the very end to
// OutTy. This is to account for dynamic stepping sizes when the value
// isn't apparent at compile time. In the (very common) case when we know
// the step size at compile time, due to haveing complete type information
// this multiplication will optmized out and produces code equivalent to a
// a GEP on a pointer of the correct type.
// Output
llvm::Value *OutPtr = nullptr;
if (CastedOutBasePtr) {
llvm::Value *OutOffset = Builder.CreateSub(IV, Arg_x1);
OutPtr = Builder.CreateGEP(CastedOutBasePtr, OutOffset);
if (PassOutByPointer) {
RootArgs.push_back(OutPtr);
}
}
// Inputs
if (NumInputs > 0) {
llvm::Value *Offset = Builder.CreateSub(IV, Arg_x1);
for (size_t Index = 0; Index < NumInputs; ++Index) {
llvm::Value *InPtr = Builder.CreateGEP(InBasePtrs[Index], Offset);
llvm::Value *Input;
if (InIsStructPointer[Index]) {
Input = InPtr;
} else {
llvm::LoadInst *InputLoad = Builder.CreateLoad(InPtr, "input");
if (gEnableRsTbaa) {
InputLoad->setMetadata("tbaa", TBAAAllocation);
}
InputLoad->setMetadata("alias.scope", AliasingScope);
Input = InputLoad;
}
RootArgs.push_back(Input);
}
}
RootArgs.append(CalleeArgs.begin(), CalleeArgs.end());
llvm::Value *RetVal = Builder.CreateCall(Function, RootArgs);
if (OutPtr && !PassOutByPointer) {
llvm::StoreInst *Store = Builder.CreateStore(RetVal, OutPtr);
if (gEnableRsTbaa) {
Store->setMetadata("tbaa", TBAAAllocation);
}
Store->setMetadata("alias.scope", AliasingScope);
}
return true;
}
/// @brief Checks if pointers to allocation internals are exposed
///
/// This function verifies if through the parameters passed to the kernel
/// or through calls to the runtime library the script gains access to
/// pointers pointing to data within a RenderScript Allocation.
/// If we know we control all loads from and stores to data within
/// RenderScript allocations and if we know the run-time internal accesses
/// are all annotated with RenderScript TBAA metadata, only then we
/// can safely use TBAA to distinguish between generic and from-allocation
/// pointers.
bool allocPointersExposed(llvm::Module &Module) {
// Old style kernel function can expose pointers to elements within
// allocations.
// TODO: Extend analysis to allow simple cases of old-style kernels.
for (size_t i = 0; i < mExportForEachCount; ++i) {
const char *Name = mExportForEachNameList[i];
uint32_t Signature = mExportForEachSignatureList[i];
if (Module.getFunction(Name) &&
!bcinfo::MetadataExtractor::hasForEachSignatureKernel(Signature)) {
return true;
}
}
// Check for library functions that expose a pointer to an Allocation or
// that are not yet annotated with RenderScript-specific tbaa information.
static const std::vector<const char *> Funcs{
// rsGetElementAt(...)
"_Z14rsGetElementAt13rs_allocationj",
"_Z14rsGetElementAt13rs_allocationjj",
"_Z14rsGetElementAt13rs_allocationjjj",
// rsSetElementAt()
"_Z14rsSetElementAt13rs_allocationPvj",
"_Z14rsSetElementAt13rs_allocationPvjj",
"_Z14rsSetElementAt13rs_allocationPvjjj",
// rsGetElementAtYuv_uchar_Y()
"_Z25rsGetElementAtYuv_uchar_Y13rs_allocationjj",
// rsGetElementAtYuv_uchar_U()
"_Z25rsGetElementAtYuv_uchar_U13rs_allocationjj",
// rsGetElementAtYuv_uchar_V()
"_Z25rsGetElementAtYuv_uchar_V13rs_allocationjj",
};
for (auto FI : Funcs) {
llvm::Function *Function = Module.getFunction(FI);
if (!Function) {
ALOGE("Missing run-time function '%s'", FI);
return true;
}
if (Function->getNumUses() > 0) {
return true;
}
}
return false;
}
/// @brief Connect RenderScript TBAA metadata to C/C++ metadata
///
/// The TBAA metadata used to annotate loads/stores from RenderScript
/// Allocations is generated in a separate TBAA tree with a
/// "RenderScript Distinct TBAA" root node. LLVM does assume may-alias for
/// all nodes in unrelated alias analysis trees. This function makes the
/// "RenderScript TBAA" node (which is parented by the Distinct TBAA root),
/// a subtree of the normal C/C++ TBAA tree aside of normal C/C++ types. With
/// the connected trees every access to an Allocation is resolved to
/// must-alias if compared to a normal C/C++ access.
void connectRenderScriptTBAAMetadata(llvm::Module &Module) {
llvm::MDBuilder MDHelper(*Context);
llvm::MDNode *TBAARenderScriptDistinct =
MDHelper.createTBAARoot("RenderScript Distinct TBAA");
llvm::MDNode *TBAARenderScript = MDHelper.createTBAANode(
"RenderScript TBAA", TBAARenderScriptDistinct);
llvm::MDNode *TBAARoot = MDHelper.createTBAARoot("Simple C/C++ TBAA");
TBAARenderScript->replaceOperandWith(1, TBAARoot);
}
virtual bool runOnModule(llvm::Module &Module) {
bool Changed = false;
this->Module = &Module;
this->Context = &Module.getContext();
this->buildTypes();
bcinfo::MetadataExtractor me(&Module);
if (!me.extract()) {
ALOGE("Could not extract metadata from module!");
return false;
}
mExportForEachCount = me.getExportForEachSignatureCount();
mExportForEachNameList = me.getExportForEachNameList();
mExportForEachSignatureList = me.getExportForEachSignatureList();
bool AllocsExposed = allocPointersExposed(Module);
for (size_t i = 0; i < mExportForEachCount; ++i) {
const char *name = mExportForEachNameList[i];
uint32_t signature = mExportForEachSignatureList[i];
llvm::Function *kernel = Module.getFunction(name);
if (kernel) {
if (bcinfo::MetadataExtractor::hasForEachSignatureKernel(signature)) {
Changed |= ExpandKernel(kernel, signature);
kernel->setLinkage(llvm::GlobalValue::InternalLinkage);
} else if (kernel->getReturnType()->isVoidTy()) {
Changed |= ExpandFunction(kernel, signature);
kernel->setLinkage(llvm::GlobalValue::InternalLinkage);
} else {
// There are some graphics root functions that are not
// expanded, but that will be called directly. For those
// functions, we can not set the linkage to internal.
}
}
}
if (gEnableRsTbaa && !AllocsExposed) {
connectRenderScriptTBAAMetadata(Module);
}
return Changed;
}
virtual const char *getPassName() const {
return "ForEach-able Function Expansion";
}
}; // end RSForEachExpandPass
} // end anonymous namespace
char RSForEachExpandPass::ID = 0;
static llvm::RegisterPass<RSForEachExpandPass> X("foreachexp", "ForEach Expand Pass");
namespace bcc {
llvm::ModulePass *
createRSForEachExpandPass(bool pEnableStepOpt){
return new RSForEachExpandPass(pEnableStepOpt);
}
} // end namespace bcc