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[OpenCL] Simplify LLVM IR generated for OpenCL blocks
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Summary:
Emit direct call of block invoke functions when possible, i.e. in case the
block is not passed as a function argument.
Also doing some refactoring of `CodeGenFunction::EmitBlockCallExpr()`

Reviewers: Anastasia, yaxunl, svenvh

Reviewed By: Anastasia

Subscribers: cfe-commits

Tags: #clang

Differential Revision: https://reviews.llvm.org/D58388

llvm-svn: 354568
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Andrew Savonichev committed Feb 21, 2019
1 parent 6561a82 commit 43fceb2
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Showing 5 changed files with 91 additions and 64 deletions.
77 changes: 37 additions & 40 deletions clang/lib/CodeGen/CGBlocks.cpp
View file
Expand Up @@ -1253,52 +1253,49 @@ RValue CodeGenFunction::EmitBlockCallExpr(const CallExpr *E,
ReturnValueSlot ReturnValue) {
const BlockPointerType *BPT =
E->getCallee()->getType()->getAs<BlockPointerType>();

llvm::Value *BlockPtr = EmitScalarExpr(E->getCallee());

// Get a pointer to the generic block literal.
// For OpenCL we generate generic AS void ptr to be able to reuse the same
// block definition for blocks with captures generated as private AS local
// variables and without captures generated as global AS program scope
// variables.
unsigned AddrSpace = 0;
if (getLangOpts().OpenCL)
AddrSpace = getContext().getTargetAddressSpace(LangAS::opencl_generic);

llvm::Type *BlockLiteralTy =
llvm::PointerType::get(CGM.getGenericBlockLiteralType(), AddrSpace);

// Bitcast the callee to a block literal.
BlockPtr =
Builder.CreatePointerCast(BlockPtr, BlockLiteralTy, "block.literal");

// Get the function pointer from the literal.
llvm::Value *FuncPtr =
Builder.CreateStructGEP(CGM.getGenericBlockLiteralType(), BlockPtr,
CGM.getLangOpts().OpenCL ? 2 : 3);

// Add the block literal.
llvm::Type *GenBlockTy = CGM.getGenericBlockLiteralType();
llvm::Value *Func = nullptr;
QualType FnType = BPT->getPointeeType();
ASTContext &Ctx = getContext();
CallArgList Args;

QualType VoidPtrQualTy = getContext().VoidPtrTy;
llvm::Type *GenericVoidPtrTy = VoidPtrTy;
if (getLangOpts().OpenCL) {
GenericVoidPtrTy = CGM.getOpenCLRuntime().getGenericVoidPointerType();
VoidPtrQualTy =
getContext().getPointerType(getContext().getAddrSpaceQualType(
getContext().VoidTy, LangAS::opencl_generic));
}

BlockPtr = Builder.CreatePointerCast(BlockPtr, GenericVoidPtrTy);
Args.add(RValue::get(BlockPtr), VoidPtrQualTy);

QualType FnType = BPT->getPointeeType();
// For OpenCL, BlockPtr is already casted to generic block literal.

// First argument of a block call is a generic block literal casted to
// generic void pointer, i.e. i8 addrspace(4)*
llvm::Value *BlockDescriptor = Builder.CreatePointerCast(
BlockPtr, CGM.getOpenCLRuntime().getGenericVoidPointerType());
QualType VoidPtrQualTy = Ctx.getPointerType(
Ctx.getAddrSpaceQualType(Ctx.VoidTy, LangAS::opencl_generic));
Args.add(RValue::get(BlockDescriptor), VoidPtrQualTy);
// And the rest of the arguments.
EmitCallArgs(Args, FnType->getAs<FunctionProtoType>(), E->arguments());

// We *can* call the block directly unless it is a function argument.
if (!isa<ParmVarDecl>(E->getCalleeDecl()))
Func = CGM.getOpenCLRuntime().getInvokeFunction(E->getCallee());
else {
llvm::Value *FuncPtr = Builder.CreateStructGEP(GenBlockTy, BlockPtr, 2);
Func = Builder.CreateAlignedLoad(FuncPtr, getPointerAlign());
}
} else {
// Bitcast the block literal to a generic block literal.
BlockPtr = Builder.CreatePointerCast(
BlockPtr, llvm::PointerType::get(GenBlockTy, 0), "block.literal");
// Get pointer to the block invoke function
llvm::Value *FuncPtr = Builder.CreateStructGEP(GenBlockTy, BlockPtr, 3);

// And the rest of the arguments.
EmitCallArgs(Args, FnType->getAs<FunctionProtoType>(), E->arguments());
// First argument is a block literal casted to a void pointer
BlockPtr = Builder.CreatePointerCast(BlockPtr, VoidPtrTy);
Args.add(RValue::get(BlockPtr), Ctx.VoidPtrTy);
// And the rest of the arguments.
EmitCallArgs(Args, FnType->getAs<FunctionProtoType>(), E->arguments());

// Load the function.
llvm::Value *Func = Builder.CreateAlignedLoad(FuncPtr, getPointerAlign());
// Load the function.
Func = Builder.CreateAlignedLoad(FuncPtr, getPointerAlign());
}

const FunctionType *FuncTy = FnType->castAs<FunctionType>();
const CGFunctionInfo &FnInfo =
Expand Down
30 changes: 22 additions & 8 deletions clang/lib/CodeGen/CGOpenCLRuntime.cpp
View file
Expand Up @@ -122,6 +122,23 @@ llvm::PointerType *CGOpenCLRuntime::getGenericVoidPointerType() {
CGM.getContext().getTargetAddressSpace(LangAS::opencl_generic));
}

// Get the block literal from an expression derived from the block expression.
// OpenCL v2.0 s6.12.5:
// Block variable declarations are implicitly qualified with const. Therefore
// all block variables must be initialized at declaration time and may not be
// reassigned.
static const BlockExpr *getBlockExpr(const Expr *E) {
const Expr *Prev = nullptr; // to make sure we do not stuck in infinite loop.
while(!isa<BlockExpr>(E) && E != Prev) {
Prev = E;
E = E->IgnoreCasts();
if (auto DR = dyn_cast<DeclRefExpr>(E)) {
E = cast<VarDecl>(DR->getDecl())->getInit();
}
}
return cast<BlockExpr>(E);
}

/// Record emitted llvm invoke function and llvm block literal for the
/// corresponding block expression.
void CGOpenCLRuntime::recordBlockInfo(const BlockExpr *E,
Expand All @@ -136,20 +153,17 @@ void CGOpenCLRuntime::recordBlockInfo(const BlockExpr *E,
EnqueuedBlockMap[E].Kernel = nullptr;
}

llvm::Function *CGOpenCLRuntime::getInvokeFunction(const Expr *E) {
return EnqueuedBlockMap[getBlockExpr(E)].InvokeFunc;
}

CGOpenCLRuntime::EnqueuedBlockInfo
CGOpenCLRuntime::emitOpenCLEnqueuedBlock(CodeGenFunction &CGF, const Expr *E) {
CGF.EmitScalarExpr(E);

// The block literal may be assigned to a const variable. Chasing down
// to get the block literal.
if (auto DR = dyn_cast<DeclRefExpr>(E)) {
E = cast<VarDecl>(DR->getDecl())->getInit();
}
E = E->IgnoreImplicit();
if (auto Cast = dyn_cast<CastExpr>(E)) {
E = Cast->getSubExpr();
}
auto *Block = cast<BlockExpr>(E);
const BlockExpr *Block = getBlockExpr(E);

assert(EnqueuedBlockMap.find(Block) != EnqueuedBlockMap.end() &&
"Block expression not emitted");
Expand Down
4 changes: 4 additions & 0 deletions clang/lib/CodeGen/CGOpenCLRuntime.h
View file
Expand Up @@ -91,6 +91,10 @@ class CGOpenCLRuntime {
/// \param Block block literal emitted for the block expression.
void recordBlockInfo(const BlockExpr *E, llvm::Function *InvokeF,
llvm::Value *Block);

/// \return LLVM block invoke function emitted for an expression derived from
/// the block expression.
llvm::Function *getInvokeFunction(const Expr *E);
};

}
Expand Down
10 changes: 2 additions & 8 deletions clang/test/CodeGenOpenCL/blocks.cl
View file
Expand Up @@ -39,11 +39,8 @@ void foo(){
// SPIR: %[[blk_gen_ptr:.*]] = addrspacecast %struct.__opencl_block_literal_generic* %[[blk_ptr]] to %struct.__opencl_block_literal_generic addrspace(4)*
// SPIR: store %struct.__opencl_block_literal_generic addrspace(4)* %[[blk_gen_ptr]], %struct.__opencl_block_literal_generic addrspace(4)** %[[block_B:.*]],
// SPIR: %[[block_literal:.*]] = load %struct.__opencl_block_literal_generic addrspace(4)*, %struct.__opencl_block_literal_generic addrspace(4)** %[[block_B]]
// SPIR: %[[invoke_addr:.*]] = getelementptr inbounds %struct.__opencl_block_literal_generic, %struct.__opencl_block_literal_generic addrspace(4)* %[[block_literal]], i32 0, i32 2
// SPIR: %[[blk_gen_ptr:.*]] = bitcast %struct.__opencl_block_literal_generic addrspace(4)* %[[block_literal]] to i8 addrspace(4)*
// SPIR: %[[invoke_func_ptr:.*]] = load i8 addrspace(4)*, i8 addrspace(4)* addrspace(4)* %[[invoke_addr]]
// SPIR: %[[invoke_func:.*]] = addrspacecast i8 addrspace(4)* %[[invoke_func_ptr]] to i32 (i8 addrspace(4)*)*
// SPIR: call {{.*}}i32 %[[invoke_func]](i8 addrspace(4)* %[[blk_gen_ptr]])
// SPIR: call {{.*}}i32 @__foo_block_invoke(i8 addrspace(4)* %[[blk_gen_ptr]])
// AMDGCN: %[[block_invoke:.*]] = getelementptr inbounds <{ i32, i32, i8*, i32 }>, <{ i32, i32, i8*, i32 }> addrspace(5)* %[[block:.*]], i32 0, i32 2
// AMDGCN: store i8* bitcast (i32 (i8*)* @__foo_block_invoke to i8*), i8* addrspace(5)* %[[block_invoke]]
// AMDGCN: %[[block_captured:.*]] = getelementptr inbounds <{ i32, i32, i8*, i32 }>, <{ i32, i32, i8*, i32 }> addrspace(5)* %[[block]], i32 0, i32 3
Expand All @@ -53,11 +50,8 @@ void foo(){
// AMDGCN: %[[blk_gen_ptr:.*]] = addrspacecast %struct.__opencl_block_literal_generic addrspace(5)* %[[blk_ptr]] to %struct.__opencl_block_literal_generic*
// AMDGCN: store %struct.__opencl_block_literal_generic* %[[blk_gen_ptr]], %struct.__opencl_block_literal_generic* addrspace(5)* %[[block_B:.*]],
// AMDGCN: %[[block_literal:.*]] = load %struct.__opencl_block_literal_generic*, %struct.__opencl_block_literal_generic* addrspace(5)* %[[block_B]]
// AMDGCN: %[[invoke_addr:.*]] = getelementptr inbounds %struct.__opencl_block_literal_generic, %struct.__opencl_block_literal_generic* %[[block_literal]], i32 0, i32 2
// AMDGCN: %[[blk_gen_ptr:.*]] = bitcast %struct.__opencl_block_literal_generic* %[[block_literal]] to i8*
// AMDGCN: %[[invoke_func_ptr:.*]] = load i8*, i8** %[[invoke_addr]]
// AMDGCN: %[[invoke_func:.*]] = bitcast i8* %[[invoke_func_ptr]] to i32 (i8*)*
// AMDGCN: call {{.*}}i32 %[[invoke_func]](i8* %[[blk_gen_ptr]])
// AMDGCN: call {{.*}}i32 @__foo_block_invoke(i8* %[[blk_gen_ptr]])

int (^ block_B)(void) = ^{
return i;
Expand Down
34 changes: 26 additions & 8 deletions clang/test/CodeGenOpenCL/cl20-device-side-enqueue.cl
View file
Expand Up @@ -312,9 +312,7 @@ kernel void device_side_enqueue(global int *a, global int *b, int i) {
};

// Uses global block literal [[BLG8]] and invoke function [[INVG8]].
// COMMON: [[r1:%.*]] = load i8 addrspace(4)*, i8 addrspace(4)* addrspace(4)* getelementptr inbounds (%struct.__opencl_block_literal_generic, %struct.__opencl_block_literal_generic addrspace(4)* addrspacecast (%struct.__opencl_block_literal_generic addrspace(1)* bitcast ({ i32, i32, i8 addrspace(4)* } addrspace(1)* [[BLG8]] to %struct.__opencl_block_literal_generic addrspace(1)*) to %struct.__opencl_block_literal_generic addrspace(4)*), i32 0, i32 2)
// COMMON: [[r2:%.*]] = addrspacecast i8 addrspace(4)* [[r1]] to void (i8 addrspace(4)*)*
// COMMON: call spir_func void [[r2]](i8 addrspace(4)* addrspacecast (i8 addrspace(1)* bitcast ({ i32, i32, i8 addrspace(4)* } addrspace(1)* [[BLG8]] to i8 addrspace(1)*) to i8 addrspace(4)*))
// COMMON: call spir_func void @__device_side_enqueue_block_invoke_11(i8 addrspace(4)* addrspacecast (i8 addrspace(1)* bitcast ({ i32, i32, i8 addrspace(4)* } addrspace(1)* [[BLG8]] to i8 addrspace(1)*) to i8 addrspace(4)*))
block_A();

// Emits global block literal [[BLG8]] and block kernel [[INVGK8]]. [[INVGK8]] calls [[INVG8]].
Expand All @@ -333,15 +331,35 @@ kernel void device_side_enqueue(global int *a, global int *b, int i) {
unsigned size = get_kernel_work_group_size(block_A);

// Uses global block literal [[BLG8]] and invoke function [[INVG8]]. Make sure no redundant block literal and invoke functions are emitted.
// COMMON: [[r1:%.*]] = load i8 addrspace(4)*, i8 addrspace(4)* addrspace(4)* getelementptr inbounds (%struct.__opencl_block_literal_generic, %struct.__opencl_block_literal_generic addrspace(4)* addrspacecast (%struct.__opencl_block_literal_generic addrspace(1)* bitcast ({ i32, i32, i8 addrspace(4)* } addrspace(1)* [[BLG8]] to %struct.__opencl_block_literal_generic addrspace(1)*) to %struct.__opencl_block_literal_generic addrspace(4)*), i32 0, i32 2)
// COMMON: [[r2:%.*]] = addrspacecast i8 addrspace(4)* [[r1]] to void (i8 addrspace(4)*)*
// COMMON: call spir_func void [[r2]](i8 addrspace(4)* addrspacecast (i8 addrspace(1)* bitcast ({ i32, i32, i8 addrspace(4)* } addrspace(1)* [[BLG8]] to i8 addrspace(1)*) to i8 addrspace(4)*))
// COMMON: call spir_func void @__device_side_enqueue_block_invoke_11(i8 addrspace(4)* addrspacecast (i8 addrspace(1)* bitcast ({ i32, i32, i8 addrspace(4)* } addrspace(1)* [[BLG8]] to i8 addrspace(1)*) to i8 addrspace(4)*))
block_A();

// Make sure that block invoke function is resolved correctly after sequence of assignements.
// COMMON: store %struct.__opencl_block_literal_generic addrspace(4)*
// COMMON-SAME: addrspacecast (%struct.__opencl_block_literal_generic addrspace(1)*
// COMMON-SAME: bitcast ({ i32, i32, i8 addrspace(4)* } addrspace(1)* [[BL_GLOBAL]] to %struct.__opencl_block_literal_generic addrspace(1)*)
// COMMON-SAME: to %struct.__opencl_block_literal_generic addrspace(4)*),
// COMMON-SAME: %struct.__opencl_block_literal_generic addrspace(4)** %b1,
bl_t b1 = block_G;
// COMMON: store %struct.__opencl_block_literal_generic addrspace(4)*
// COMMON-SAME: addrspacecast (%struct.__opencl_block_literal_generic addrspace(1)*
// COMMON-SAME: bitcast ({ i32, i32, i8 addrspace(4)* } addrspace(1)* [[BL_GLOBAL]] to %struct.__opencl_block_literal_generic addrspace(1)*)
// COMMON-SAME: to %struct.__opencl_block_literal_generic addrspace(4)*),
// COMMON-SAME: %struct.__opencl_block_literal_generic addrspace(4)** %b2,
bl_t b2 = b1;
// COMMON: call spir_func void @block_G_block_invoke(i8 addrspace(4)* addrspacecast (i8 addrspace(1)*
// COMMON-SAME: bitcast ({ i32, i32, i8 addrspace(4)* } addrspace(1)* [[BL_GLOBAL]] to i8 addrspace(1)*)
// COOMON-SAME: to i8 addrspace(4)*), i8 addrspace(3)* null)
b2(0);
// Uses global block literal [[BL_GLOBAL]] and block kernel [[INV_G_K]]. [[INV_G_K]] calls [[INV_G]].
// COMMON: call i32 @__get_kernel_preferred_work_group_size_multiple_impl(
// COMMON-SAME: i8 addrspace(4)* addrspacecast (i8* bitcast ({{.*}} [[INV_G_K:[^ ]+_kernel]] to i8*) to i8 addrspace(4)*),
// COMMON-SAME: i8 addrspace(4)* addrspacecast (i8 addrspace(1)* bitcast ({ i32, i32, i8 addrspace(4)* } addrspace(1)* [[BL_GLOBAL]] to i8 addrspace(1)*) to i8 addrspace(4)*))
size = get_kernel_preferred_work_group_size_multiple(b2);

void (^block_C)(void) = ^{
callee(i, a);
};

// Emits block literal on stack and block kernel [[INVLK3]].
// COMMON: store i8 addrspace(4)* addrspacecast (i8* bitcast (void (i8 addrspace(4)*)* [[INVL3:@__device_side_enqueue_block_invoke[^ ]*]] to i8*) to i8 addrspace(4)*), i8 addrspace(4)** %block.invoke
// COMMON: [[DEF_Q:%[0-9]+]] = load %opencl.queue_t{{.*}}*, %opencl.queue_t{{.*}}** %default_queue
Expand Down Expand Up @@ -404,8 +422,8 @@ kernel void device_side_enqueue(global int *a, global int *b, int i) {
// COMMON: define internal spir_func void [[INVG8]](i8 addrspace(4)*{{.*}})
// COMMON: define internal spir_func void [[INVG9]](i8 addrspace(4)*{{.*}}, i8 addrspace(3)* %{{.*}})
// COMMON: define internal spir_kernel void [[INVGK8]](i8 addrspace(4)*{{.*}})
// COMMON: define internal spir_kernel void [[INV_G_K]](i8 addrspace(4)*{{.*}}, i8 addrspace(3)*{{.*}})
// COMMON: define internal spir_kernel void [[INVLK3]](i8 addrspace(4)*{{.*}})
// COMMON: define internal spir_kernel void [[INVGK9]](i8 addrspace(4)*{{.*}}, i8 addrspace(3)*{{.*}})
// COMMON: define internal spir_kernel void [[INV_G_K]](i8 addrspace(4)*{{.*}}, i8 addrspace(3)*{{.*}})
// COMMON: define internal spir_kernel void [[INVGK10]](i8 addrspace(4)*{{.*}})
// COMMON: define internal spir_kernel void [[INVGK11]](i8 addrspace(4)*{{.*}})

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