slang_backend.cpp revision a1f95ee8df425089100148a42954cf61dc285015 
1/*
2 * Copyright 2010-2012, 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 "bcinfo/BitcodeWrapper.h"
23
24#include "clang/AST/ASTContext.h"
25#include "clang/AST/Decl.h"
26#include "clang/AST/DeclGroup.h"
27
28#include "clang/Basic/Diagnostic.h"
29#include "clang/Basic/TargetInfo.h"
30#include "clang/Basic/TargetOptions.h"
31
32#include "clang/CodeGen/ModuleBuilder.h"
33
34#include "clang/Frontend/CodeGenOptions.h"
35#include "clang/Frontend/FrontendDiagnostic.h"
36
37#include "llvm/Assembly/PrintModulePass.h"
38
39#include "llvm/Bitcode/ReaderWriter.h"
40
41#include "llvm/CodeGen/RegAllocRegistry.h"
42#include "llvm/CodeGen/SchedulerRegistry.h"
43
44#include "llvm/IR/LLVMContext.h"
45#include "llvm/IR/Module.h"
46#include "llvm/IR/Metadata.h"
47
48#include "llvm/Transforms/IPO/PassManagerBuilder.h"
49
50#include "llvm/IR/DataLayout.h"
51#include "llvm/Target/TargetMachine.h"
52#include "llvm/Target/TargetOptions.h"
53#include "llvm/Support/TargetRegistry.h"
54
55#include "llvm/MC/SubtargetFeature.h"
56
57#include "slang_assert.h"
58#include "BitWriter_2_9/ReaderWriter_2_9.h"
59#include "BitWriter_2_9_func/ReaderWriter_2_9_func.h"
60#include "BitWriter_3_2/ReaderWriter_3_2.h"
61
62namespace slang {
63
64void Backend::CreateFunctionPasses() {
65  if (!mPerFunctionPasses) {
66    mPerFunctionPasses = new llvm::FunctionPassManager(mpModule);
67    mPerFunctionPasses->add(new llvm::DataLayout(mpModule));
68
69    llvm::PassManagerBuilder PMBuilder;
70    PMBuilder.OptLevel = mCodeGenOpts.OptimizationLevel;
71    PMBuilder.populateFunctionPassManager(*mPerFunctionPasses);
72  }
73  return;
74}
75
76void Backend::CreateModulePasses() {
77  if (!mPerModulePasses) {
78    mPerModulePasses = new llvm::PassManager();
79    mPerModulePasses->add(new llvm::DataLayout(mpModule));
80
81    llvm::PassManagerBuilder PMBuilder;
82    PMBuilder.OptLevel = mCodeGenOpts.OptimizationLevel;
83    PMBuilder.SizeLevel = mCodeGenOpts.OptimizeSize;
84    PMBuilder.SizeLevel = mCodeGenOpts.OptimizeSize;
85    if (mCodeGenOpts.UnitAtATime) {
86      PMBuilder.DisableUnitAtATime = 0;
87    } else {
88      PMBuilder.DisableUnitAtATime = 1;
89    }
90
91    if (mCodeGenOpts.UnrollLoops) {
92      PMBuilder.DisableUnrollLoops = 0;
93    } else {
94      PMBuilder.DisableUnrollLoops = 1;
95    }
96
97    PMBuilder.populateModulePassManager(*mPerModulePasses);
98  }
99  return;
100}
101
102bool Backend::CreateCodeGenPasses() {
103  if ((mOT != Slang::OT_Assembly) && (mOT != Slang::OT_Object))
104    return true;
105
106  // Now we add passes for code emitting
107  if (mCodeGenPasses) {
108    return true;
109  } else {
110    mCodeGenPasses = new llvm::FunctionPassManager(mpModule);
111    mCodeGenPasses->add(new llvm::DataLayout(mpModule));
112  }
113
114  // Create the TargetMachine for generating code.
115  std::string Triple = mpModule->getTargetTriple();
116
117  std::string Error;
118  const llvm::Target* TargetInfo =
119      llvm::TargetRegistry::lookupTarget(Triple, Error);
120  if (TargetInfo == NULL) {
121    mDiagEngine.Report(clang::diag::err_fe_unable_to_create_target) << Error;
122    return false;
123  }
124
125  // Target Machine Options
126  llvm::TargetOptions Options;
127
128  Options.NoFramePointerElim = mCodeGenOpts.DisableFPElim;
129
130  // Use hardware FPU.
131  //
132  // FIXME: Need to detect the CPU capability and decide whether to use softfp.
133  // To use softfp, change following 2 lines to
134  //
135  // Options.FloatABIType = llvm::FloatABI::Soft;
136  // Options.UseSoftFloat = true;
137  Options.FloatABIType = llvm::FloatABI::Hard;
138  Options.UseSoftFloat = false;
139
140  // BCC needs all unknown symbols resolved at compilation time. So we don't
141  // need any relocation model.
142  llvm::Reloc::Model RM = llvm::Reloc::Static;
143
144  // This is set for the linker (specify how large of the virtual addresses we
145  // can access for all unknown symbols.)
146  llvm::CodeModel::Model CM;
147  if (mpModule->getPointerSize() == llvm::Module::Pointer32) {
148    CM = llvm::CodeModel::Small;
149  } else {
150    // The target may have pointer size greater than 32 (e.g. x86_64
151    // architecture) may need large data address model
152    CM = llvm::CodeModel::Medium;
153  }
154
155  // Setup feature string
156  std::string FeaturesStr;
157  if (mTargetOpts.CPU.size() || mTargetOpts.Features.size()) {
158    llvm::SubtargetFeatures Features;
159
160    for (std::vector<std::string>::const_iterator
161             I = mTargetOpts.Features.begin(), E = mTargetOpts.Features.end();
162         I != E;
163         I++)
164      Features.AddFeature(*I);
165
166    FeaturesStr = Features.getString();
167  }
168
169  llvm::TargetMachine *TM =
170    TargetInfo->createTargetMachine(Triple, mTargetOpts.CPU, FeaturesStr,
171                                    Options, RM, CM);
172
173  // Register scheduler
174  llvm::RegisterScheduler::setDefault(llvm::createDefaultScheduler);
175
176  // Register allocation policy:
177  //  createFastRegisterAllocator: fast but bad quality
178  //  createGreedyRegisterAllocator: not so fast but good quality
179  llvm::RegisterRegAlloc::setDefault((mCodeGenOpts.OptimizationLevel == 0) ?
180                                     llvm::createFastRegisterAllocator :
181                                     llvm::createGreedyRegisterAllocator);
182
183  llvm::CodeGenOpt::Level OptLevel = llvm::CodeGenOpt::Default;
184  if (mCodeGenOpts.OptimizationLevel == 0) {
185    OptLevel = llvm::CodeGenOpt::None;
186  } else if (mCodeGenOpts.OptimizationLevel == 3) {
187    OptLevel = llvm::CodeGenOpt::Aggressive;
188  }
189
190  llvm::TargetMachine::CodeGenFileType CGFT =
191      llvm::TargetMachine::CGFT_AssemblyFile;
192  if (mOT == Slang::OT_Object) {
193    CGFT = llvm::TargetMachine::CGFT_ObjectFile;
194  }
195  if (TM->addPassesToEmitFile(*mCodeGenPasses, FormattedOutStream,
196                              CGFT, OptLevel)) {
197    mDiagEngine.Report(clang::diag::err_fe_unable_to_interface_with_target);
198    return false;
199  }
200
201  return true;
202}
203
204Backend::Backend(clang::DiagnosticsEngine *DiagEngine,
205                 const clang::CodeGenOptions &CodeGenOpts,
206                 const clang::TargetOptions &TargetOpts,
207                 PragmaList *Pragmas,
208                 llvm::raw_ostream *OS,
209                 Slang::OutputType OT)
210    : ASTConsumer(),
211      mTargetOpts(TargetOpts),
212      mpModule(NULL),
213      mpOS(OS),
214      mOT(OT),
215      mGen(NULL),
216      mPerFunctionPasses(NULL),
217      mPerModulePasses(NULL),
218      mCodeGenPasses(NULL),
219      mLLVMContext(llvm::getGlobalContext()),
220      mDiagEngine(*DiagEngine),
221      mCodeGenOpts(CodeGenOpts),
222      mPragmas(Pragmas) {
223  FormattedOutStream.setStream(*mpOS,
224                               llvm::formatted_raw_ostream::PRESERVE_STREAM);
225  mGen = CreateLLVMCodeGen(mDiagEngine, "", mCodeGenOpts,
226                           mTargetOpts, mLLVMContext);
227  return;
228}
229
230void Backend::Initialize(clang::ASTContext &Ctx) {
231  mGen->Initialize(Ctx);
232
233  mpModule = mGen->GetModule();
234
235  return;
236}
237
238// Encase the Bitcode in a wrapper containing RS version information.
239void Backend::WrapBitcode(llvm::raw_string_ostream &Bitcode) {
240  bcinfo::AndroidBitcodeWrapper wrapper;
241  size_t actualWrapperLen = bcinfo::writeAndroidBitcodeWrapper(
242      &wrapper, Bitcode.str().length(), getTargetAPI(),
243      SlangVersion::CURRENT, mCodeGenOpts.OptimizationLevel);
244
245  slangAssert(actualWrapperLen > 0);
246
247  // Write out the bitcode wrapper.
248  FormattedOutStream.write(reinterpret_cast<char*>(&wrapper), actualWrapperLen);
249
250  // Write out the actual encoded bitcode.
251  FormattedOutStream << Bitcode.str();
252  return;
253}
254
255bool Backend::HandleTopLevelDecl(clang::DeclGroupRef D) {
256  return mGen->HandleTopLevelDecl(D);
257}
258
259void Backend::HandleTranslationUnit(clang::ASTContext &Ctx) {
260  HandleTranslationUnitPre(Ctx);
261
262  mGen->HandleTranslationUnit(Ctx);
263
264  // Here, we complete a translation unit (whole translation unit is now in LLVM
265  // IR). Now, interact with LLVM backend to generate actual machine code (asm
266  // or machine code, whatever.)
267
268  // Silently ignore if we weren't initialized for some reason.
269  if (!mpModule)
270    return;
271
272  llvm::Module *M = mGen->ReleaseModule();
273  if (!M) {
274    // The module has been released by IR gen on failures, do not double free.
275    mpModule = NULL;
276    return;
277  }
278
279  slangAssert(mpModule == M &&
280              "Unexpected module change during LLVM IR generation");
281
282  // Insert #pragma information into metadata section of module
283  if (!mPragmas->empty()) {
284    llvm::NamedMDNode *PragmaMetadata =
285        mpModule->getOrInsertNamedMetadata(Slang::PragmaMetadataName);
286    for (PragmaList::const_iterator I = mPragmas->begin(), E = mPragmas->end();
287         I != E;
288         I++) {
289      llvm::SmallVector<llvm::Value*, 2> Pragma;
290      // Name goes first
291      Pragma.push_back(llvm::MDString::get(mLLVMContext, I->first));
292      // And then value
293      Pragma.push_back(llvm::MDString::get(mLLVMContext, I->second));
294
295      // Create MDNode and insert into PragmaMetadata
296      PragmaMetadata->addOperand(
297          llvm::MDNode::get(mLLVMContext, Pragma));
298    }
299  }
300
301  HandleTranslationUnitPost(mpModule);
302
303  // Create passes for optimization and code emission
304
305  // Create and run per-function passes
306  CreateFunctionPasses();
307  if (mPerFunctionPasses) {
308    mPerFunctionPasses->doInitialization();
309
310    for (llvm::Module::iterator I = mpModule->begin(), E = mpModule->end();
311         I != E;
312         I++)
313      if (!I->isDeclaration())
314        mPerFunctionPasses->run(*I);
315
316    mPerFunctionPasses->doFinalization();
317  }
318
319  // Create and run module passes
320  CreateModulePasses();
321  if (mPerModulePasses)
322    mPerModulePasses->run(*mpModule);
323
324  switch (mOT) {
325    case Slang::OT_Assembly:
326    case Slang::OT_Object: {
327      if (!CreateCodeGenPasses())
328        return;
329
330      mCodeGenPasses->doInitialization();
331
332      for (llvm::Module::iterator I = mpModule->begin(), E = mpModule->end();
333          I != E;
334          I++)
335        if (!I->isDeclaration())
336          mCodeGenPasses->run(*I);
337
338      mCodeGenPasses->doFinalization();
339      break;
340    }
341    case Slang::OT_LLVMAssembly: {
342      llvm::PassManager *LLEmitPM = new llvm::PassManager();
343      LLEmitPM->add(llvm::createPrintModulePass(&FormattedOutStream));
344      LLEmitPM->run(*mpModule);
345      break;
346    }
347    case Slang::OT_Bitcode: {
348      llvm::PassManager *BCEmitPM = new llvm::PassManager();
349      std::string BCStr;
350      llvm::raw_string_ostream Bitcode(BCStr);
351      unsigned int TargetAPI = getTargetAPI();
352      switch (TargetAPI) {
353        case SLANG_HC_TARGET_API:
354        case SLANG_HC_MR1_TARGET_API:
355        case SLANG_HC_MR2_TARGET_API: {
356          // Pre-ICS targets must use the LLVM 2.9 BitcodeWriter
357          BCEmitPM->add(llvm_2_9::createBitcodeWriterPass(Bitcode));
358          break;
359        }
360        case SLANG_ICS_TARGET_API:
361        case SLANG_ICS_MR1_TARGET_API: {
362          // ICS targets must use the LLVM 2.9_func BitcodeWriter
363          BCEmitPM->add(llvm_2_9_func::createBitcodeWriterPass(Bitcode));
364          break;
365        }
366        default: {
367          if (TargetAPI < SLANG_MINIMUM_TARGET_API ||
368              TargetAPI > SLANG_MAXIMUM_TARGET_API) {
369            slangAssert(false && "Invalid target API value");
370          }
371          // Switch to the 3.2 BitcodeWriter by default, and don't use
372          // LLVM's included BitcodeWriter at all (for now).
373          BCEmitPM->add(llvm_3_2::createBitcodeWriterPass(Bitcode));
374          //BCEmitPM->add(llvm::createBitcodeWriterPass(Bitcode));
375          break;
376        }
377      }
378
379      BCEmitPM->run(*mpModule);
380      WrapBitcode(Bitcode);
381      break;
382    }
383    case Slang::OT_Nothing: {
384      return;
385    }
386    default: {
387      slangAssert(false && "Unknown output type");
388    }
389  }
390
391  FormattedOutStream.flush();
392
393  return;
394}
395
396void Backend::HandleTagDeclDefinition(clang::TagDecl *D) {
397  mGen->HandleTagDeclDefinition(D);
398  return;
399}
400
401void Backend::CompleteTentativeDefinition(clang::VarDecl *D) {
402  mGen->CompleteTentativeDefinition(D);
403  return;
404}
405
406Backend::~Backend() {
407  delete mpModule;
408  delete mGen;
409  delete mPerFunctionPasses;
410  delete mPerModulePasses;
411  delete mCodeGenPasses;
412  return;
413}
414
415}  // namespace slang
416