slang_backend.cpp revision 18c8829f2bd3cbe0d02471588c6643c0a8c6ca3c 
1/*
2 * Copyright 2010, 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 "slang_backend.h"
18
19#include <string>
20#include <vector>
21
22#include "clang/AST/ASTContext.h"
23#include "clang/AST/Decl.h"
24#include "clang/AST/DeclGroup.h"
25
26#include "clang/Basic/Diagnostic.h"
27#include "clang/Basic/TargetInfo.h"
28#include "clang/Basic/TargetOptions.h"
29
30#include "clang/CodeGen/ModuleBuilder.h"
31
32#include "clang/Frontend/CodeGenOptions.h"
33#include "clang/Frontend/FrontendDiagnostic.h"
34
35#include "llvm/Assembly/PrintModulePass.h"
36
37#include "llvm/Bitcode/ReaderWriter.h"
38
39#include "llvm/CodeGen/RegAllocRegistry.h"
40#include "llvm/CodeGen/SchedulerRegistry.h"
41
42#include "llvm/LLVMContext.h"
43#include "llvm/Module.h"
44#include "llvm/Metadata.h"
45
46#include "llvm/Support/PassManagerBuilder.h"
47
48#include "llvm/Target/TargetData.h"
49#include "llvm/Target/TargetMachine.h"
50#include "llvm/Target/TargetOptions.h"
51#include "llvm/Target/TargetRegistry.h"
52
53#include "llvm/MC/SubtargetFeature.h"
54
55#include "slang.h"
56#include "slang_assert.h"
57
58namespace slang {
59
60void Backend::CreateFunctionPasses() {
61  if (!mPerFunctionPasses) {
62    mPerFunctionPasses = new llvm::FunctionPassManager(mpModule);
63    mPerFunctionPasses->add(new llvm::TargetData(mpModule));
64
65    llvm::PassManagerBuilder PMBuilder;
66    PMBuilder.OptLevel = mCodeGenOpts.OptimizationLevel;
67    PMBuilder.populateFunctionPassManager(*mPerFunctionPasses);
68  }
69  return;
70}
71
72void Backend::CreateModulePasses() {
73  if (!mPerModulePasses) {
74    mPerModulePasses = new llvm::PassManager();
75    mPerModulePasses->add(new llvm::TargetData(mpModule));
76
77    llvm::PassManagerBuilder PMBuilder;
78    PMBuilder.OptLevel = mCodeGenOpts.OptimizationLevel;
79    PMBuilder.SizeLevel = mCodeGenOpts.OptimizeSize;
80    PMBuilder.SizeLevel = mCodeGenOpts.OptimizeSize;
81    if (mCodeGenOpts.UnitAtATime) {
82      PMBuilder.DisableUnitAtATime = 0;
83    } else {
84      PMBuilder.DisableUnitAtATime = 1;
85    }
86
87    if (mCodeGenOpts.UnrollLoops) {
88      PMBuilder.DisableUnrollLoops = 0;
89    } else {
90      PMBuilder.DisableUnrollLoops = 1;
91    }
92
93    PMBuilder.DisableSimplifyLibCalls = false;
94    PMBuilder.populateModulePassManager(*mPerModulePasses);
95  }
96  return;
97}
98
99bool Backend::CreateCodeGenPasses() {
100  if ((mOT != Slang::OT_Assembly) && (mOT != Slang::OT_Object))
101    return true;
102
103  // Now we add passes for code emitting
104  if (mCodeGenPasses) {
105    return true;
106  } else {
107    mCodeGenPasses = new llvm::FunctionPassManager(mpModule);
108    mCodeGenPasses->add(new llvm::TargetData(mpModule));
109  }
110
111  // Create the TargetMachine for generating code.
112  std::string Triple = mpModule->getTargetTriple();
113
114  std::string Error;
115  const llvm::Target* TargetInfo =
116      llvm::TargetRegistry::lookupTarget(Triple, Error);
117  if (TargetInfo == NULL) {
118    mDiags.Report(clang::diag::err_fe_unable_to_create_target) << Error;
119    return false;
120  }
121
122  llvm::NoFramePointerElim = mCodeGenOpts.DisableFPElim;
123
124  // Use hardware FPU.
125  //
126  // FIXME: Need to detect the CPU capability and decide whether to use softfp.
127  // To use softfp, change following 2 lines to
128  //
129  //  llvm::FloatABIType = llvm::FloatABI::Soft;
130  //  llvm::UseSoftFloat = true;
131  llvm::FloatABIType = llvm::FloatABI::Hard;
132  llvm::UseSoftFloat = false;
133
134  // BCC needs all unknown symbols resolved at compilation time. So we don't
135  // need any relocation model.
136  llvm::TargetMachine::setRelocationModel(llvm::Reloc::Static);
137
138
139  // This is set for the linker (specify how large of the virtual addresses we
140  // can access for all unknown symbols.)
141  if (mpModule->getPointerSize() == llvm::Module::Pointer32)
142    llvm::TargetMachine::setCodeModel(llvm::CodeModel::Small);
143  else
144    // The target may have pointer size greater than 32 (e.g. x86_64
145    // architecture) may need large data address model
146    llvm::TargetMachine::setCodeModel(llvm::CodeModel::Medium);
147
148  // Setup feature string
149  std::string FeaturesStr;
150  if (mTargetOpts.CPU.size() || mTargetOpts.Features.size()) {
151    llvm::SubtargetFeatures Features;
152
153    for (std::vector<std::string>::const_iterator
154             I = mTargetOpts.Features.begin(), E = mTargetOpts.Features.end();
155         I != E;
156         I++)
157      Features.AddFeature(*I);
158
159    FeaturesStr = Features.getString();
160  }
161  llvm::TargetMachine *TM =
162      TargetInfo->createTargetMachine(Triple, mTargetOpts.CPU, FeaturesStr);
163
164  // Register scheduler
165  llvm::RegisterScheduler::setDefault(llvm::createDefaultScheduler);
166
167  // Register allocation policy:
168  //  createFastRegisterAllocator: fast but bad quality
169  //  createLinearScanRegisterAllocator: not so fast but good quality
170  llvm::RegisterRegAlloc::setDefault((mCodeGenOpts.OptimizationLevel == 0) ?
171                                     llvm::createFastRegisterAllocator :
172                                     llvm::createLinearScanRegisterAllocator);
173
174  llvm::CodeGenOpt::Level OptLevel = llvm::CodeGenOpt::Default;
175  if (mCodeGenOpts.OptimizationLevel == 0) {
176    OptLevel = llvm::CodeGenOpt::None;
177  } else if (mCodeGenOpts.OptimizationLevel == 3) {
178    OptLevel = llvm::CodeGenOpt::Aggressive;
179  }
180
181  llvm::TargetMachine::CodeGenFileType CGFT =
182      llvm::TargetMachine::CGFT_AssemblyFile;
183  if (mOT == Slang::OT_Object) {
184    CGFT = llvm::TargetMachine::CGFT_ObjectFile;
185  }
186  if (TM->addPassesToEmitFile(*mCodeGenPasses, FormattedOutStream,
187                              CGFT, OptLevel)) {
188    mDiags.Report(clang::diag::err_fe_unable_to_interface_with_target);
189    return false;
190  }
191
192  return true;
193}
194
195Backend::Backend(clang::Diagnostic *Diags,
196                 const clang::CodeGenOptions &CodeGenOpts,
197                 const clang::TargetOptions &TargetOpts,
198                 PragmaList *Pragmas,
199                 llvm::raw_ostream *OS,
200                 Slang::OutputType OT)
201    : ASTConsumer(),
202      mCodeGenOpts(CodeGenOpts),
203      mTargetOpts(TargetOpts),
204      mpModule(NULL),
205      mpOS(OS),
206      mOT(OT),
207      mGen(NULL),
208      mPerFunctionPasses(NULL),
209      mPerModulePasses(NULL),
210      mCodeGenPasses(NULL),
211      mLLVMContext(llvm::getGlobalContext()),
212      mDiags(*Diags),
213      mPragmas(Pragmas) {
214  FormattedOutStream.setStream(*mpOS,
215                               llvm::formatted_raw_ostream::PRESERVE_STREAM);
216  mGen = CreateLLVMCodeGen(mDiags, "", mCodeGenOpts, mLLVMContext);
217  return;
218}
219
220void Backend::Initialize(clang::ASTContext &Ctx) {
221  mGen->Initialize(Ctx);
222
223  mpModule = mGen->GetModule();
224
225  return;
226}
227
228void Backend::HandleTopLevelDecl(clang::DeclGroupRef D) {
229  mGen->HandleTopLevelDecl(D);
230  return;
231}
232
233void Backend::HandleTranslationUnit(clang::ASTContext &Ctx) {
234  HandleTranslationUnitPre(Ctx);
235
236  mGen->HandleTranslationUnit(Ctx);
237
238  // Here, we complete a translation unit (whole translation unit is now in LLVM
239  // IR). Now, interact with LLVM backend to generate actual machine code (asm
240  // or machine code, whatever.)
241
242  // Silently ignore if we weren't initialized for some reason.
243  if (!mpModule)
244    return;
245
246  llvm::Module *M = mGen->ReleaseModule();
247  if (!M) {
248    // The module has been released by IR gen on failures, do not double free.
249    mpModule = NULL;
250    return;
251  }
252
253  slangAssert(mpModule == M &&
254              "Unexpected module change during LLVM IR generation");
255
256  // Insert #pragma information into metadata section of module
257  if (!mPragmas->empty()) {
258    llvm::NamedMDNode *PragmaMetadata =
259        mpModule->getOrInsertNamedMetadata(Slang::PragmaMetadataName);
260    for (PragmaList::const_iterator I = mPragmas->begin(), E = mPragmas->end();
261         I != E;
262         I++) {
263      llvm::SmallVector<llvm::Value*, 2> Pragma;
264      // Name goes first
265      Pragma.push_back(llvm::MDString::get(mLLVMContext, I->first));
266      // And then value
267      Pragma.push_back(llvm::MDString::get(mLLVMContext, I->second));
268
269      // Create MDNode and insert into PragmaMetadata
270      PragmaMetadata->addOperand(
271          llvm::MDNode::get(mLLVMContext, Pragma));
272    }
273  }
274
275  HandleTranslationUnitPost(mpModule);
276
277  // Create passes for optimization and code emission
278
279  // Create and run per-function passes
280  CreateFunctionPasses();
281  if (mPerFunctionPasses) {
282    mPerFunctionPasses->doInitialization();
283
284    for (llvm::Module::iterator I = mpModule->begin(), E = mpModule->end();
285         I != E;
286         I++)
287      if (!I->isDeclaration())
288        mPerFunctionPasses->run(*I);
289
290    mPerFunctionPasses->doFinalization();
291  }
292
293  // Create and run module passes
294  CreateModulePasses();
295  if (mPerModulePasses)
296    mPerModulePasses->run(*mpModule);
297
298  switch (mOT) {
299    case Slang::OT_Assembly:
300    case Slang::OT_Object: {
301      if (!CreateCodeGenPasses())
302        return;
303
304      mCodeGenPasses->doInitialization();
305
306      for (llvm::Module::iterator I = mpModule->begin(), E = mpModule->end();
307          I != E;
308          I++)
309        if (!I->isDeclaration())
310          mCodeGenPasses->run(*I);
311
312      mCodeGenPasses->doFinalization();
313      break;
314    }
315    case Slang::OT_LLVMAssembly: {
316      llvm::PassManager *LLEmitPM = new llvm::PassManager();
317      LLEmitPM->add(llvm::createPrintModulePass(&FormattedOutStream));
318      LLEmitPM->run(*mpModule);
319      break;
320    }
321    case Slang::OT_Bitcode: {
322      llvm::PassManager *BCEmitPM = new llvm::PassManager();
323      BCEmitPM->add(llvm::createBitcodeWriterPass(FormattedOutStream));
324      BCEmitPM->run(*mpModule);
325      break;
326    }
327    case Slang::OT_Nothing: {
328      return;
329    }
330    default: {
331      slangAssert(false && "Unknown output type");
332    }
333  }
334
335  FormattedOutStream.flush();
336
337  return;
338}
339
340void Backend::HandleTagDeclDefinition(clang::TagDecl *D) {
341  mGen->HandleTagDeclDefinition(D);
342  return;
343}
344
345void Backend::CompleteTentativeDefinition(clang::VarDecl *D) {
346  mGen->CompleteTentativeDefinition(D);
347  return;
348}
349
350Backend::~Backend() {
351  delete mpModule;
352  delete mGen;
353  delete mPerFunctionPasses;
354  delete mPerModulePasses;
355  delete mCodeGenPasses;
356  return;
357}
358
359}  // namespace slang
360