1 /* Copyright 2017 The TensorFlow Authors. All Rights Reserved.
2
3 Licensed under the Apache License, Version 2.0 (the "License");
4 you may not use this file except in compliance with the License.
5 You may obtain a copy of the License at
6
7 http://www.apache.org/licenses/LICENSE-2.0
8
9 Unless required by applicable law or agreed to in writing, software
10 distributed under the License is distributed on an "AS IS" BASIS,
11 WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
12 See the License for the specific language governing permissions and
13 limitations under the License.
14 ==============================================================================*/
15
16 #include "tensorflow/compiler/xla/service/llvm_ir/tuple_ops.h"
17
18 #include <stddef.h>
19 #include <string>
20 #include <vector>
21
22 #include "llvm/IR/Instructions.h"
23 #include "tensorflow/compiler/xla/service/llvm_ir/llvm_util.h"
24 #include "tensorflow/compiler/xla/shape_util.h"
25 #include "tensorflow/compiler/xla/types.h"
26 #include "tensorflow/compiler/xla/xla_data.pb.h"
27 #include "tensorflow/core/platform/logging.h"
28
29 namespace xla {
30 namespace llvm_ir {
31
getModuleFromBuilder(llvm::IRBuilder<> * b)32 static llvm::Module* getModuleFromBuilder(llvm::IRBuilder<>* b) {
33 return b->GetInsertBlock()->getModule();
34 }
35
EmitTupleSelect(const IrArray & select,const IrArray & pred,llvm::Value * on_true,llvm::Value * on_false,llvm::IRBuilder<> * b)36 void EmitTupleSelect(const IrArray& select, const IrArray& pred,
37 llvm::Value* on_true, llvm::Value* on_false,
38 llvm::IRBuilder<>* b) {
39 llvm::Module* module = getModuleFromBuilder(b);
40 CHECK(ShapeUtil::IsScalar(pred.GetShape()));
41
42 llvm::LoadInst* pred_value =
43 b->CreateLoad(pred.GetBasePointer(), "load_predicate_value");
44 llvm::Value* pred_cond = b->CreateICmpNE(
45 pred_value,
46 llvm::ConstantInt::get(PrimitiveTypeToIrType(PRED, module), 0),
47 "boolean_predicate");
48
49 VLOG(2) << "HandleSelect for tuple:";
50 VLOG(2) << " pred_value: " << DumpToString(*pred_value);
51 VLOG(2) << " pred_cond: " << DumpToString(*pred_cond);
52
53 llvm::Value* src = b->CreateSelect(pred_cond, on_true, on_false);
54 llvm::Value* dst = select.GetBasePointer();
55 int64 table_size = ShapeUtil::ByteSizeOfTupleIndexTable(
56 select.GetShape(), module->getDataLayout().getPointerSize());
57 b->CreateMemCpy(dst, /*DstAlign=*/llvm::Align(1), src,
58 /*SrcAlign=*/llvm::Align(1), b->getInt64(table_size));
59 }
60
EmitTuple(const IrArray & tuple,absl::Span<llvm::Value * const> operands,llvm::IRBuilder<> * b)61 void EmitTuple(const IrArray& tuple, absl::Span<llvm::Value* const> operands,
62 llvm::IRBuilder<>* b) {
63 llvm::Module* module = getModuleFromBuilder(b);
64 for (size_t i = 0; i < operands.size(); ++i) {
65 auto* cast =
66 b->CreatePointerCast(operands[i], PrimitiveTypeToIrType(TUPLE, module));
67 auto* store = b->CreateStore(
68 cast, b->CreateInBoundsGEP(tuple.GetBasePointer(),
69 {b->getInt64(0), b->getInt64(i)}));
70 tuple.AnnotateLoadStoreInstructionWithMetadata(store);
71 }
72 }
73
EmitTuple(const IrArray & tuple,absl::Span<const IrArray> buffers,llvm::IRBuilder<> * b)74 void EmitTuple(const IrArray& tuple, absl::Span<const IrArray> buffers,
75 llvm::IRBuilder<>* b) {
76 std::vector<llvm::Value*> buffer_ptrs;
77 buffer_ptrs.reserve(buffers.size());
78 absl::c_transform(
79 buffers, std::back_inserter(buffer_ptrs),
80 [](const llvm_ir::IrArray& buffer) { return buffer.GetBasePointer(); });
81 llvm_ir::EmitTuple(tuple, buffer_ptrs, b);
82 }
83
EmitTupleAllocasAtFunctionEntry(const Shape & tuple_shape,llvm::IRBuilder<> * b)84 std::vector<llvm::Value*> EmitTupleAllocasAtFunctionEntry(
85 const Shape& tuple_shape, llvm::IRBuilder<>* b) {
86 llvm::Module* module = b->GetInsertBlock()->getModule();
87
88 llvm::IRBuilder<>::InsertPointGuard guard(*b);
89 llvm::Function* function = b->GetInsertBlock()->getParent();
90 b->SetInsertPoint(&function->getEntryBlock(),
91 function->getEntryBlock().getFirstInsertionPt());
92 CHECK(tuple_shape.IsTuple());
93 int tuple_size = tuple_shape.tuple_shapes_size();
94
95 std::vector<llvm::Value*> generated_allocas;
96 for (int i = 0; i < tuple_size; i++) {
97 const Shape& element_shape = tuple_shape.tuple_shapes(i);
98 CHECK(ShapeUtil::IsScalar(element_shape));
99 llvm::Type* type =
100 llvm_ir::PrimitiveTypeToIrType(element_shape.element_type(), module);
101 llvm::AllocaInst* alloca = b->CreateAlloca(
102 type,
103 /*ArraySize=*/nullptr, AsStringRef(absl::StrCat("tuple_element_", i)));
104 generated_allocas.push_back(alloca);
105 }
106
107 return generated_allocas;
108 }
109
EmitGetTupleElement(const Shape & target_shape,int64 index,int alignment,llvm::Value * operand,llvm::IRBuilder<> * b)110 llvm::Value* EmitGetTupleElement(const Shape& target_shape, int64 index,
111 int alignment, llvm::Value* operand,
112 llvm::IRBuilder<>* b) {
113 llvm::Module* module = getModuleFromBuilder(b);
114 llvm::Value* element_ptr =
115 b->CreateInBoundsGEP(operand, {b->getInt64(0), b->getInt64(index)});
116 llvm::LoadInst* src_buffer = b->CreateLoad(element_ptr);
117
118 // Mark the loaded pointer as dereferenceable if we know its shape.
119 if (!target_shape.IsOpaque()) {
120 SetDereferenceableMetadataForLoad(
121 src_buffer,
122 ByteSizeOf(target_shape, src_buffer->getModule()->getDataLayout()));
123 }
124 SetAlignmentMetadataForLoad(src_buffer, alignment);
125
126 llvm::Type* element_type = ShapeToIrType(target_shape, module);
127 llvm::Value* ret_val =
128 b->CreateBitCast(src_buffer, element_type->getPointerTo());
129 return ret_val;
130 }
131
132 } // namespace llvm_ir
133 } // namespace xla
134