1 /*
2 * Copyright (C) 2015 The Android Open Source Project
3 *
4 * Licensed under the Apache License, Version 2.0 (the "License");
5 * you may not use this file except in compliance with the License.
6 * You may obtain a copy of the License at
7 *
8 * http://www.apache.org/licenses/LICENSE-2.0
9 *
10 * Unless required by applicable law or agreed to in writing, software
11 * distributed under the License is distributed on an "AS IS" BASIS,
12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13 * See the License for the specific language governing permissions and
14 * limitations under the License.
15 */
16
17 #include "pc_relative_fixups_x86.h"
18 #include "code_generator_x86.h"
19 #include "intrinsics_x86.h"
20
21 namespace art {
22 namespace x86 {
23
24 /**
25 * Finds instructions that need the constant area base as an input.
26 */
27 class PCRelativeHandlerVisitor : public HGraphVisitor {
28 public:
PCRelativeHandlerVisitor(HGraph * graph,CodeGenerator * codegen)29 PCRelativeHandlerVisitor(HGraph* graph, CodeGenerator* codegen)
30 : HGraphVisitor(graph),
31 codegen_(down_cast<CodeGeneratorX86*>(codegen)),
32 base_(nullptr) {}
33
MoveBaseIfNeeded()34 void MoveBaseIfNeeded() {
35 if (base_ != nullptr) {
36 // Bring the base closer to the first use (previously, it was in the
37 // entry block) and relieve some pressure on the register allocator
38 // while avoiding recalculation of the base in a loop.
39 base_->MoveBeforeFirstUserAndOutOfLoops();
40 }
41 }
42
43 private:
VisitAdd(HAdd * add)44 void VisitAdd(HAdd* add) override {
45 BinaryFP(add);
46 }
47
VisitSub(HSub * sub)48 void VisitSub(HSub* sub) override {
49 BinaryFP(sub);
50 }
51
VisitMul(HMul * mul)52 void VisitMul(HMul* mul) override {
53 BinaryFP(mul);
54 }
55
VisitDiv(HDiv * div)56 void VisitDiv(HDiv* div) override {
57 BinaryFP(div);
58 }
59
VisitCompare(HCompare * compare)60 void VisitCompare(HCompare* compare) override {
61 BinaryFP(compare);
62 }
63
VisitReturn(HReturn * ret)64 void VisitReturn(HReturn* ret) override {
65 HConstant* value = ret->InputAt(0)->AsConstant();
66 if ((value != nullptr && DataType::IsFloatingPointType(value->GetType()))) {
67 ReplaceInput(ret, value, 0, true);
68 }
69 }
70
VisitInvokeStaticOrDirect(HInvokeStaticOrDirect * invoke)71 void VisitInvokeStaticOrDirect(HInvokeStaticOrDirect* invoke) override {
72 HandleInvoke(invoke);
73 }
74
VisitInvokeVirtual(HInvokeVirtual * invoke)75 void VisitInvokeVirtual(HInvokeVirtual* invoke) override {
76 HandleInvoke(invoke);
77 }
78
VisitInvokeInterface(HInvokeInterface * invoke)79 void VisitInvokeInterface(HInvokeInterface* invoke) override {
80 HandleInvoke(invoke);
81 }
82
VisitLoadClass(HLoadClass * load_class)83 void VisitLoadClass(HLoadClass* load_class) override {
84 if (load_class->HasPcRelativeLoadKind()) {
85 HX86ComputeBaseMethodAddress* method_address = GetPCRelativeBasePointer(load_class);
86 load_class->AddSpecialInput(method_address);
87 }
88 }
89
VisitLoadString(HLoadString * load_string)90 void VisitLoadString(HLoadString* load_string) override {
91 if (load_string->HasPcRelativeLoadKind()) {
92 HX86ComputeBaseMethodAddress* method_address = GetPCRelativeBasePointer(load_string);
93 load_string->AddSpecialInput(method_address);
94 }
95 }
96
BinaryFP(HBinaryOperation * bin)97 void BinaryFP(HBinaryOperation* bin) {
98 HConstant* rhs = bin->InputAt(1)->AsConstant();
99 if (rhs != nullptr && DataType::IsFloatingPointType(rhs->GetType())) {
100 ReplaceInput(bin, rhs, 1, false);
101 }
102 }
103
VisitEqual(HEqual * cond)104 void VisitEqual(HEqual* cond) override {
105 BinaryFP(cond);
106 }
107
VisitNotEqual(HNotEqual * cond)108 void VisitNotEqual(HNotEqual* cond) override {
109 BinaryFP(cond);
110 }
111
VisitLessThan(HLessThan * cond)112 void VisitLessThan(HLessThan* cond) override {
113 BinaryFP(cond);
114 }
115
VisitLessThanOrEqual(HLessThanOrEqual * cond)116 void VisitLessThanOrEqual(HLessThanOrEqual* cond) override {
117 BinaryFP(cond);
118 }
119
VisitGreaterThan(HGreaterThan * cond)120 void VisitGreaterThan(HGreaterThan* cond) override {
121 BinaryFP(cond);
122 }
123
VisitGreaterThanOrEqual(HGreaterThanOrEqual * cond)124 void VisitGreaterThanOrEqual(HGreaterThanOrEqual* cond) override {
125 BinaryFP(cond);
126 }
127
VisitNeg(HNeg * neg)128 void VisitNeg(HNeg* neg) override {
129 if (DataType::IsFloatingPointType(neg->GetType())) {
130 // We need to replace the HNeg with a HX86FPNeg in order to address the constant area.
131 HX86ComputeBaseMethodAddress* method_address = GetPCRelativeBasePointer(neg);
132 HGraph* graph = GetGraph();
133 HBasicBlock* block = neg->GetBlock();
134 HX86FPNeg* x86_fp_neg = new (graph->GetAllocator()) HX86FPNeg(
135 neg->GetType(),
136 neg->InputAt(0),
137 method_address,
138 neg->GetDexPc());
139 block->ReplaceAndRemoveInstructionWith(neg, x86_fp_neg);
140 }
141 }
142
VisitPackedSwitch(HPackedSwitch * switch_insn)143 void VisitPackedSwitch(HPackedSwitch* switch_insn) override {
144 if (switch_insn->GetNumEntries() <=
145 InstructionCodeGeneratorX86::kPackedSwitchJumpTableThreshold) {
146 return;
147 }
148 // We need to replace the HPackedSwitch with a HX86PackedSwitch in order to
149 // address the constant area.
150 HX86ComputeBaseMethodAddress* method_address = GetPCRelativeBasePointer(switch_insn);
151 HGraph* graph = GetGraph();
152 HBasicBlock* block = switch_insn->GetBlock();
153 HX86PackedSwitch* x86_switch = new (graph->GetAllocator()) HX86PackedSwitch(
154 switch_insn->GetStartValue(),
155 switch_insn->GetNumEntries(),
156 switch_insn->InputAt(0),
157 method_address,
158 switch_insn->GetDexPc());
159 block->ReplaceAndRemoveInstructionWith(switch_insn, x86_switch);
160 }
161
GetPCRelativeBasePointer(HInstruction * cursor)162 HX86ComputeBaseMethodAddress* GetPCRelativeBasePointer(HInstruction* cursor) {
163 bool has_irreducible_loops = GetGraph()->HasIrreducibleLoops();
164 if (!has_irreducible_loops) {
165 // Ensure we only initialize the pointer once.
166 if (base_ != nullptr) {
167 return base_;
168 }
169 }
170 // Insert the base at the start of the entry block, move it to a better
171 // position later in MoveBaseIfNeeded().
172 HX86ComputeBaseMethodAddress* method_address =
173 new (GetGraph()->GetAllocator()) HX86ComputeBaseMethodAddress();
174 if (has_irreducible_loops) {
175 cursor->GetBlock()->InsertInstructionBefore(method_address, cursor);
176 } else {
177 HBasicBlock* entry_block = GetGraph()->GetEntryBlock();
178 entry_block->InsertInstructionBefore(method_address, entry_block->GetFirstInstruction());
179 base_ = method_address;
180 }
181 return method_address;
182 }
183
ReplaceInput(HInstruction * insn,HConstant * value,int input_index,bool materialize)184 void ReplaceInput(HInstruction* insn, HConstant* value, int input_index, bool materialize) {
185 HX86ComputeBaseMethodAddress* method_address = GetPCRelativeBasePointer(insn);
186 HX86LoadFromConstantTable* load_constant =
187 new (GetGraph()->GetAllocator()) HX86LoadFromConstantTable(method_address, value);
188 if (!materialize) {
189 load_constant->MarkEmittedAtUseSite();
190 }
191 insn->GetBlock()->InsertInstructionBefore(load_constant, insn);
192 insn->ReplaceInput(load_constant, input_index);
193 }
194
HandleInvoke(HInvoke * invoke)195 void HandleInvoke(HInvoke* invoke) {
196 HInvokeStaticOrDirect* invoke_static_or_direct = invoke->AsInvokeStaticOrDirect();
197
198 // If this is an invoke-static/-direct with PC-relative addressing (within boot image
199 // or using .bss or .data.bimg.rel.ro), we need the PC-relative address base.
200 bool base_added = false;
201 if (invoke_static_or_direct != nullptr &&
202 invoke_static_or_direct->HasPcRelativeMethodLoadKind() &&
203 !IsCallFreeIntrinsic<IntrinsicLocationsBuilderX86>(invoke, codegen_)) {
204 HX86ComputeBaseMethodAddress* method_address = GetPCRelativeBasePointer(invoke);
205 // Add the extra parameter.
206 invoke_static_or_direct->AddSpecialInput(method_address);
207 base_added = true;
208 }
209
210 // Ensure that we can load FP arguments from the constant area.
211 HInputsRef inputs = invoke->GetInputs();
212 for (size_t i = 0; i < inputs.size(); i++) {
213 HConstant* input = inputs[i]->AsConstant();
214 if (input != nullptr && DataType::IsFloatingPointType(input->GetType())) {
215 ReplaceInput(invoke, input, i, true);
216 }
217 }
218
219 switch (invoke->GetIntrinsic()) {
220 case Intrinsics::kMathAbsDouble:
221 case Intrinsics::kMathAbsFloat:
222 case Intrinsics::kMathMaxDoubleDouble:
223 case Intrinsics::kMathMaxFloatFloat:
224 case Intrinsics::kMathMinDoubleDouble:
225 case Intrinsics::kMathMinFloatFloat:
226 LOG(FATAL) << "Unreachable min/max/abs: intrinsics should have been lowered "
227 "to IR nodes by instruction simplifier";
228 UNREACHABLE();
229 case Intrinsics::kIntegerValueOf:
230 // This intrinsic can be call free if it loads the address of the boot image object.
231 // If we're compiling PIC, we need the address base for loading from .data.bimg.rel.ro.
232 if (!codegen_->GetCompilerOptions().GetCompilePic()) {
233 break;
234 }
235 FALLTHROUGH_INTENDED;
236 case Intrinsics::kMathRoundFloat:
237 // This intrinsic needs the constant area.
238 if (!base_added) {
239 DCHECK(invoke_static_or_direct != nullptr);
240 HX86ComputeBaseMethodAddress* method_address = GetPCRelativeBasePointer(invoke);
241 invoke_static_or_direct->AddSpecialInput(method_address);
242 }
243 break;
244 default:
245 break;
246 }
247 }
248
249 CodeGeneratorX86* codegen_;
250
251 // The generated HX86ComputeBaseMethodAddress in the entry block needed as an
252 // input to the HX86LoadFromConstantTable instructions. Only set for
253 // graphs with reducible loops.
254 HX86ComputeBaseMethodAddress* base_;
255 };
256
Run()257 bool PcRelativeFixups::Run() {
258 PCRelativeHandlerVisitor visitor(graph_, codegen_);
259 visitor.VisitInsertionOrder();
260 visitor.MoveBaseIfNeeded();
261 return true;
262 }
263
264 } // namespace x86
265 } // namespace art
266