slang_backend.cpp revision 796e7b1400d3f3f7c07496d88bb48129ea925bb9 
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/IR/IRPrintingPasses.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 "strip_unknown_attributes.h"
59#include "BitWriter_2_9/ReaderWriter_2_9.h"
60#include "BitWriter_2_9_func/ReaderWriter_2_9_func.h"
61#include "BitWriter_3_2/ReaderWriter_3_2.h"
62
63namespace slang {
64
65void Backend::CreateFunctionPasses() {
66  if (!mPerFunctionPasses) {
67    mPerFunctionPasses = new llvm::FunctionPassManager(mpModule);
68    mPerFunctionPasses->add(new llvm::DataLayoutPass(mpModule));
69
70    llvm::PassManagerBuilder PMBuilder;
71    PMBuilder.OptLevel = mCodeGenOpts.OptimizationLevel;
72    PMBuilder.populateFunctionPassManager(*mPerFunctionPasses);
73  }
74}
75
76void Backend::CreateModulePasses() {
77  if (!mPerModulePasses) {
78    mPerModulePasses = new llvm::PassManager();
79    mPerModulePasses->add(new llvm::DataLayoutPass(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    // Add a pass to strip off unknown/unsupported attributes.
99    mPerModulePasses->add(createStripUnknownAttributesPass());
100  }
101}
102
103bool Backend::CreateCodeGenPasses() {
104  if ((mOT != Slang::OT_Assembly) && (mOT != Slang::OT_Object))
105    return true;
106
107  // Now we add passes for code emitting
108  if (mCodeGenPasses) {
109    return true;
110  } else {
111    mCodeGenPasses = new llvm::FunctionPassManager(mpModule);
112    mCodeGenPasses->add(new llvm::DataLayoutPass(mpModule));
113  }
114
115  // Create the TargetMachine for generating code.
116  std::string Triple = mpModule->getTargetTriple();
117
118  std::string Error;
119  const llvm::Target* TargetInfo =
120      llvm::TargetRegistry::lookupTarget(Triple, Error);
121  if (TargetInfo == NULL) {
122    mDiagEngine.Report(clang::diag::err_fe_unable_to_create_target) << Error;
123    return false;
124  }
125
126  // Target Machine Options
127  llvm::TargetOptions Options;
128
129  Options.NoFramePointerElim = mCodeGenOpts.DisableFPElim;
130
131  // Use hardware FPU.
132  //
133  // FIXME: Need to detect the CPU capability and decide whether to use softfp.
134  // To use softfp, change following 2 lines to
135  //
136  // Options.FloatABIType = llvm::FloatABI::Soft;
137  // Options.UseSoftFloat = true;
138  Options.FloatABIType = llvm::FloatABI::Hard;
139  Options.UseSoftFloat = false;
140
141  // BCC needs all unknown symbols resolved at compilation time. So we don't
142  // need any relocation model.
143  llvm::Reloc::Model RM = llvm::Reloc::Static;
144
145  // This is set for the linker (specify how large of the virtual addresses we
146  // can access for all unknown symbols.)
147  llvm::CodeModel::Model CM;
148  if (mpModule->getDataLayout()->getPointerSize() == 4) {
149    CM = llvm::CodeModel::Small;
150  } else {
151    // The target may have pointer size greater than 32 (e.g. x86_64
152    // architecture) may need large data address model
153    CM = llvm::CodeModel::Medium;
154  }
155
156  // Setup feature string
157  std::string FeaturesStr;
158  if (mTargetOpts.CPU.size() || mTargetOpts.Features.size()) {
159    llvm::SubtargetFeatures Features;
160
161    for (std::vector<std::string>::const_iterator
162             I = mTargetOpts.Features.begin(), E = mTargetOpts.Features.end();
163         I != E;
164         I++)
165      Features.AddFeature(*I);
166
167    FeaturesStr = Features.getString();
168  }
169
170  llvm::TargetMachine *TM =
171    TargetInfo->createTargetMachine(Triple, mTargetOpts.CPU, FeaturesStr,
172                                    Options, RM, CM);
173
174  // Register scheduler
175  llvm::RegisterScheduler::setDefault(llvm::createDefaultScheduler);
176
177  // Register allocation policy:
178  //  createFastRegisterAllocator: fast but bad quality
179  //  createGreedyRegisterAllocator: not so fast but good quality
180  llvm::RegisterRegAlloc::setDefault((mCodeGenOpts.OptimizationLevel == 0) ?
181                                     llvm::createFastRegisterAllocator :
182                                     llvm::createGreedyRegisterAllocator);
183
184  llvm::CodeGenOpt::Level OptLevel = llvm::CodeGenOpt::Default;
185  if (mCodeGenOpts.OptimizationLevel == 0) {
186    OptLevel = llvm::CodeGenOpt::None;
187  } else if (mCodeGenOpts.OptimizationLevel == 3) {
188    OptLevel = llvm::CodeGenOpt::Aggressive;
189  }
190
191  llvm::TargetMachine::CodeGenFileType CGFT =
192      llvm::TargetMachine::CGFT_AssemblyFile;
193  if (mOT == Slang::OT_Object) {
194    CGFT = llvm::TargetMachine::CGFT_ObjectFile;
195  }
196  if (TM->addPassesToEmitFile(*mCodeGenPasses, FormattedOutStream,
197                              CGFT, OptLevel)) {
198    mDiagEngine.Report(clang::diag::err_fe_unable_to_interface_with_target);
199    return false;
200  }
201
202  return true;
203}
204
205Backend::Backend(clang::DiagnosticsEngine *DiagEngine,
206                 const clang::CodeGenOptions &CodeGenOpts,
207                 const clang::TargetOptions &TargetOpts,
208                 PragmaList *Pragmas,
209                 llvm::raw_ostream *OS,
210                 Slang::OutputType OT)
211    : ASTConsumer(),
212      mTargetOpts(TargetOpts),
213      mpModule(NULL),
214      mpOS(OS),
215      mOT(OT),
216      mGen(NULL),
217      mPerFunctionPasses(NULL),
218      mPerModulePasses(NULL),
219      mCodeGenPasses(NULL),
220      mLLVMContext(llvm::getGlobalContext()),
221      mDiagEngine(*DiagEngine),
222      mCodeGenOpts(CodeGenOpts),
223      mPragmas(Pragmas) {
224  FormattedOutStream.setStream(*mpOS,
225                               llvm::formatted_raw_ostream::PRESERVE_STREAM);
226  mGen = CreateLLVMCodeGen(mDiagEngine, "", mCodeGenOpts,
227                           mTargetOpts, mLLVMContext);
228}
229
230void Backend::Initialize(clang::ASTContext &Ctx) {
231  mGen->Initialize(Ctx);
232
233  mpModule = mGen->GetModule();
234}
235
236// Encase the Bitcode in a wrapper containing RS version information.
237void Backend::WrapBitcode(llvm::raw_string_ostream &Bitcode) {
238  bcinfo::AndroidBitcodeWrapper wrapper;
239  size_t actualWrapperLen = bcinfo::writeAndroidBitcodeWrapper(
240      &wrapper, Bitcode.str().length(), getTargetAPI(),
241      SlangVersion::CURRENT, mCodeGenOpts.OptimizationLevel);
242
243  slangAssert(actualWrapperLen > 0);
244
245  // Write out the bitcode wrapper.
246  FormattedOutStream.write(reinterpret_cast<char*>(&wrapper), actualWrapperLen);
247
248  // Write out the actual encoded bitcode.
249  FormattedOutStream << Bitcode.str();
250}
251
252bool Backend::HandleTopLevelDecl(clang::DeclGroupRef D) {
253  return mGen->HandleTopLevelDecl(D);
254}
255
256void Backend::HandleTranslationUnit(clang::ASTContext &Ctx) {
257  HandleTranslationUnitPre(Ctx);
258
259  mGen->HandleTranslationUnit(Ctx);
260
261  // Here, we complete a translation unit (whole translation unit is now in LLVM
262  // IR). Now, interact with LLVM backend to generate actual machine code (asm
263  // or machine code, whatever.)
264
265  // Silently ignore if we weren't initialized for some reason.
266  if (!mpModule)
267    return;
268
269  llvm::Module *M = mGen->ReleaseModule();
270  if (!M) {
271    // The module has been released by IR gen on failures, do not double free.
272    mpModule = NULL;
273    return;
274  }
275
276  slangAssert(mpModule == M &&
277              "Unexpected module change during LLVM IR generation");
278
279  // Insert #pragma information into metadata section of module
280  if (!mPragmas->empty()) {
281    llvm::NamedMDNode *PragmaMetadata =
282        mpModule->getOrInsertNamedMetadata(Slang::PragmaMetadataName);
283    for (PragmaList::const_iterator I = mPragmas->begin(), E = mPragmas->end();
284         I != E;
285         I++) {
286      llvm::SmallVector<llvm::Value*, 2> Pragma;
287      // Name goes first
288      Pragma.push_back(llvm::MDString::get(mLLVMContext, I->first));
289      // And then value
290      Pragma.push_back(llvm::MDString::get(mLLVMContext, I->second));
291
292      // Create MDNode and insert into PragmaMetadata
293      PragmaMetadata->addOperand(
294          llvm::MDNode::get(mLLVMContext, Pragma));
295    }
296  }
297
298  HandleTranslationUnitPost(mpModule);
299
300  // Create passes for optimization and code emission
301
302  // Create and run per-function passes
303  CreateFunctionPasses();
304  if (mPerFunctionPasses) {
305    mPerFunctionPasses->doInitialization();
306
307    for (llvm::Module::iterator I = mpModule->begin(), E = mpModule->end();
308         I != E;
309         I++)
310      if (!I->isDeclaration())
311        mPerFunctionPasses->run(*I);
312
313    mPerFunctionPasses->doFinalization();
314  }
315
316  // Create and run module passes
317  CreateModulePasses();
318  if (mPerModulePasses)
319    mPerModulePasses->run(*mpModule);
320
321  switch (mOT) {
322    case Slang::OT_Assembly:
323    case Slang::OT_Object: {
324      if (!CreateCodeGenPasses())
325        return;
326
327      mCodeGenPasses->doInitialization();
328
329      for (llvm::Module::iterator I = mpModule->begin(), E = mpModule->end();
330          I != E;
331          I++)
332        if (!I->isDeclaration())
333          mCodeGenPasses->run(*I);
334
335      mCodeGenPasses->doFinalization();
336      break;
337    }
338    case Slang::OT_LLVMAssembly: {
339      llvm::PassManager *LLEmitPM = new llvm::PassManager();
340      LLEmitPM->add(llvm::createPrintModulePass(FormattedOutStream));
341      LLEmitPM->run(*mpModule);
342      break;
343    }
344    case Slang::OT_Bitcode: {
345      llvm::PassManager *BCEmitPM = new llvm::PassManager();
346      std::string BCStr;
347      llvm::raw_string_ostream Bitcode(BCStr);
348      unsigned int TargetAPI = getTargetAPI();
349      switch (TargetAPI) {
350        case SLANG_HC_TARGET_API:
351        case SLANG_HC_MR1_TARGET_API:
352        case SLANG_HC_MR2_TARGET_API: {
353          // Pre-ICS targets must use the LLVM 2.9 BitcodeWriter
354          BCEmitPM->add(llvm_2_9::createBitcodeWriterPass(Bitcode));
355          break;
356        }
357        case SLANG_ICS_TARGET_API:
358        case SLANG_ICS_MR1_TARGET_API: {
359          // ICS targets must use the LLVM 2.9_func BitcodeWriter
360          BCEmitPM->add(llvm_2_9_func::createBitcodeWriterPass(Bitcode));
361          break;
362        }
363        default: {
364          if (TargetAPI < SLANG_MINIMUM_TARGET_API ||
365              TargetAPI > SLANG_MAXIMUM_TARGET_API) {
366            slangAssert(false && "Invalid target API value");
367          }
368          // Switch to the 3.2 BitcodeWriter by default, and don't use
369          // LLVM's included BitcodeWriter at all (for now).
370          BCEmitPM->add(llvm_3_2::createBitcodeWriterPass(Bitcode));
371          //BCEmitPM->add(llvm::createBitcodeWriterPass(Bitcode));
372          break;
373        }
374      }
375
376      BCEmitPM->run(*mpModule);
377      WrapBitcode(Bitcode);
378      break;
379    }
380    case Slang::OT_Nothing: {
381      return;
382    }
383    default: {
384      slangAssert(false && "Unknown output type");
385    }
386  }
387
388  FormattedOutStream.flush();
389}
390
391void Backend::HandleTagDeclDefinition(clang::TagDecl *D) {
392  mGen->HandleTagDeclDefinition(D);
393}
394
395void Backend::CompleteTentativeDefinition(clang::VarDecl *D) {
396  mGen->CompleteTentativeDefinition(D);
397}
398
399Backend::~Backend() {
400  delete mpModule;
401  delete mGen;
402  delete mPerFunctionPasses;
403  delete mPerModulePasses;
404  delete mCodeGenPasses;
405}
406
407}  // namespace slang
408