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 && Primitive::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 HLoadClass::LoadKind load_kind = load_class->GetLoadKind();
85 if (load_kind == HLoadClass::LoadKind::kBootImageLinkTimePcRelative ||
86 load_kind == HLoadClass::LoadKind::kBssEntry) {
87 HX86ComputeBaseMethodAddress* method_address = GetPCRelativeBasePointer(load_class);
88 load_class->AddSpecialInput(method_address);
89 }
90 }
91
VisitLoadString(HLoadString * load_string)92 void VisitLoadString(HLoadString* load_string) OVERRIDE {
93 HLoadString::LoadKind load_kind = load_string->GetLoadKind();
94 if (load_kind == HLoadString::LoadKind::kBootImageLinkTimePcRelative ||
95 load_kind == HLoadString::LoadKind::kBssEntry) {
96 HX86ComputeBaseMethodAddress* method_address = GetPCRelativeBasePointer(load_string);
97 load_string->AddSpecialInput(method_address);
98 }
99 }
100
BinaryFP(HBinaryOperation * bin)101 void BinaryFP(HBinaryOperation* bin) {
102 HConstant* rhs = bin->InputAt(1)->AsConstant();
103 if (rhs != nullptr && Primitive::IsFloatingPointType(rhs->GetType())) {
104 ReplaceInput(bin, rhs, 1, false);
105 }
106 }
107
VisitEqual(HEqual * cond)108 void VisitEqual(HEqual* cond) OVERRIDE {
109 BinaryFP(cond);
110 }
111
VisitNotEqual(HNotEqual * cond)112 void VisitNotEqual(HNotEqual* cond) OVERRIDE {
113 BinaryFP(cond);
114 }
115
VisitLessThan(HLessThan * cond)116 void VisitLessThan(HLessThan* cond) OVERRIDE {
117 BinaryFP(cond);
118 }
119
VisitLessThanOrEqual(HLessThanOrEqual * cond)120 void VisitLessThanOrEqual(HLessThanOrEqual* cond) OVERRIDE {
121 BinaryFP(cond);
122 }
123
VisitGreaterThan(HGreaterThan * cond)124 void VisitGreaterThan(HGreaterThan* cond) OVERRIDE {
125 BinaryFP(cond);
126 }
127
VisitGreaterThanOrEqual(HGreaterThanOrEqual * cond)128 void VisitGreaterThanOrEqual(HGreaterThanOrEqual* cond) OVERRIDE {
129 BinaryFP(cond);
130 }
131
VisitNeg(HNeg * neg)132 void VisitNeg(HNeg* neg) OVERRIDE {
133 if (Primitive::IsFloatingPointType(neg->GetType())) {
134 // We need to replace the HNeg with a HX86FPNeg in order to address the constant area.
135 HX86ComputeBaseMethodAddress* method_address = GetPCRelativeBasePointer(neg);
136 HGraph* graph = GetGraph();
137 HBasicBlock* block = neg->GetBlock();
138 HX86FPNeg* x86_fp_neg = new (graph->GetArena()) HX86FPNeg(
139 neg->GetType(),
140 neg->InputAt(0),
141 method_address,
142 neg->GetDexPc());
143 block->ReplaceAndRemoveInstructionWith(neg, x86_fp_neg);
144 }
145 }
146
VisitPackedSwitch(HPackedSwitch * switch_insn)147 void VisitPackedSwitch(HPackedSwitch* switch_insn) OVERRIDE {
148 if (switch_insn->GetNumEntries() <=
149 InstructionCodeGeneratorX86::kPackedSwitchJumpTableThreshold) {
150 return;
151 }
152 // We need to replace the HPackedSwitch with a HX86PackedSwitch in order to
153 // address the constant area.
154 HX86ComputeBaseMethodAddress* method_address = GetPCRelativeBasePointer(switch_insn);
155 HGraph* graph = GetGraph();
156 HBasicBlock* block = switch_insn->GetBlock();
157 HX86PackedSwitch* x86_switch = new (graph->GetArena()) HX86PackedSwitch(
158 switch_insn->GetStartValue(),
159 switch_insn->GetNumEntries(),
160 switch_insn->InputAt(0),
161 method_address,
162 switch_insn->GetDexPc());
163 block->ReplaceAndRemoveInstructionWith(switch_insn, x86_switch);
164 }
165
GetPCRelativeBasePointer(HInstruction * cursor)166 HX86ComputeBaseMethodAddress* GetPCRelativeBasePointer(HInstruction* cursor) {
167 bool has_irreducible_loops = GetGraph()->HasIrreducibleLoops();
168 if (!has_irreducible_loops) {
169 // Ensure we only initialize the pointer once.
170 if (base_ != nullptr) {
171 return base_;
172 }
173 }
174 // Insert the base at the start of the entry block, move it to a better
175 // position later in MoveBaseIfNeeded().
176 HX86ComputeBaseMethodAddress* method_address =
177 new (GetGraph()->GetArena()) HX86ComputeBaseMethodAddress();
178 if (has_irreducible_loops) {
179 cursor->GetBlock()->InsertInstructionBefore(method_address, cursor);
180 } else {
181 HBasicBlock* entry_block = GetGraph()->GetEntryBlock();
182 entry_block->InsertInstructionBefore(method_address, entry_block->GetFirstInstruction());
183 base_ = method_address;
184 }
185 return method_address;
186 }
187
ReplaceInput(HInstruction * insn,HConstant * value,int input_index,bool materialize)188 void ReplaceInput(HInstruction* insn, HConstant* value, int input_index, bool materialize) {
189 HX86ComputeBaseMethodAddress* method_address = GetPCRelativeBasePointer(insn);
190 HX86LoadFromConstantTable* load_constant =
191 new (GetGraph()->GetArena()) HX86LoadFromConstantTable(method_address, value);
192 if (!materialize) {
193 load_constant->MarkEmittedAtUseSite();
194 }
195 insn->GetBlock()->InsertInstructionBefore(load_constant, insn);
196 insn->ReplaceInput(load_constant, input_index);
197 }
198
HandleInvoke(HInvoke * invoke)199 void HandleInvoke(HInvoke* invoke) {
200 // If this is an invoke-static/-direct with PC-relative dex cache array
201 // addressing, we need the PC-relative address base.
202 HInvokeStaticOrDirect* invoke_static_or_direct = invoke->AsInvokeStaticOrDirect();
203 // We can't add a pointer to the constant area if we already have a current
204 // method pointer. This may arise when sharpening doesn't remove the current
205 // method pointer from the invoke.
206 if (invoke_static_or_direct != nullptr &&
207 invoke_static_or_direct->HasCurrentMethodInput()) {
208 DCHECK(!invoke_static_or_direct->HasPcRelativeDexCache());
209 return;
210 }
211
212 bool base_added = false;
213 if (invoke_static_or_direct != nullptr &&
214 invoke_static_or_direct->HasPcRelativeDexCache() &&
215 !IsCallFreeIntrinsic<IntrinsicLocationsBuilderX86>(invoke, codegen_)) {
216 HX86ComputeBaseMethodAddress* method_address = GetPCRelativeBasePointer(invoke);
217 // Add the extra parameter.
218 invoke_static_or_direct->AddSpecialInput(method_address);
219 base_added = true;
220 }
221
222 // Ensure that we can load FP arguments from the constant area.
223 HInputsRef inputs = invoke->GetInputs();
224 for (size_t i = 0; i < inputs.size(); i++) {
225 HConstant* input = inputs[i]->AsConstant();
226 if (input != nullptr && Primitive::IsFloatingPointType(input->GetType())) {
227 ReplaceInput(invoke, input, i, true);
228 }
229 }
230
231 // These intrinsics need the constant area.
232 switch (invoke->GetIntrinsic()) {
233 case Intrinsics::kMathAbsDouble:
234 case Intrinsics::kMathAbsFloat:
235 case Intrinsics::kMathMaxDoubleDouble:
236 case Intrinsics::kMathMaxFloatFloat:
237 case Intrinsics::kMathMinDoubleDouble:
238 case Intrinsics::kMathMinFloatFloat:
239 case Intrinsics::kMathRoundFloat:
240 if (!base_added) {
241 DCHECK(invoke_static_or_direct != nullptr);
242 DCHECK(!invoke_static_or_direct->HasCurrentMethodInput());
243 HX86ComputeBaseMethodAddress* method_address = GetPCRelativeBasePointer(invoke);
244 invoke_static_or_direct->AddSpecialInput(method_address);
245 }
246 break;
247 default:
248 break;
249 }
250 }
251
252 CodeGeneratorX86* codegen_;
253
254 // The generated HX86ComputeBaseMethodAddress in the entry block needed as an
255 // input to the HX86LoadFromConstantTable instructions. Only set for
256 // graphs with reducible loops.
257 HX86ComputeBaseMethodAddress* base_;
258 };
259
Run()260 void PcRelativeFixups::Run() {
261 PCRelativeHandlerVisitor visitor(graph_, codegen_);
262 visitor.VisitInsertionOrder();
263 visitor.MoveBaseIfNeeded();
264 }
265
266 } // namespace x86
267 } // namespace art
268