1 //===--- CodeGenAction.cpp - LLVM Code Generation Frontend Action ---------===//
2 //
3 //                     The LLVM Compiler Infrastructure
4 //
5 // This file is distributed under the University of Illinois Open Source
6 // License. See LICENSE.TXT for details.
7 //
8 //===----------------------------------------------------------------------===//
9 
10 #include "clang/CodeGen/CodeGenAction.h"
11 #include "clang/AST/ASTConsumer.h"
12 #include "clang/AST/ASTContext.h"
13 #include "clang/AST/DeclGroup.h"
14 #include "clang/Basic/FileManager.h"
15 #include "clang/Basic/SourceManager.h"
16 #include "clang/Basic/TargetInfo.h"
17 #include "clang/CodeGen/BackendUtil.h"
18 #include "clang/CodeGen/ModuleBuilder.h"
19 #include "clang/Frontend/CompilerInstance.h"
20 #include "clang/Frontend/FrontendDiagnostic.h"
21 #include "llvm/ADT/OwningPtr.h"
22 #include "llvm/ADT/SmallString.h"
23 #include "llvm/Bitcode/ReaderWriter.h"
24 #include "llvm/IR/LLVMContext.h"
25 #include "llvm/IR/Module.h"
26 #include "llvm/IRReader/IRReader.h"
27 #include "llvm/Linker.h"
28 #include "llvm/Pass.h"
29 #include "llvm/Support/MemoryBuffer.h"
30 #include "llvm/Support/SourceMgr.h"
31 #include "llvm/Support/Timer.h"
32 using namespace clang;
33 using namespace llvm;
34 
35 namespace clang {
36   class BackendConsumer : public ASTConsumer {
37     virtual void anchor();
38     DiagnosticsEngine &Diags;
39     BackendAction Action;
40     const CodeGenOptions &CodeGenOpts;
41     const TargetOptions &TargetOpts;
42     const LangOptions &LangOpts;
43     raw_ostream *AsmOutStream;
44     ASTContext *Context;
45 
46     Timer LLVMIRGeneration;
47 
48     OwningPtr<CodeGenerator> Gen;
49 
50     OwningPtr<llvm::Module> TheModule, LinkModule;
51 
52   public:
53     BackendConsumer(BackendAction action, DiagnosticsEngine &_Diags,
54                     const CodeGenOptions &compopts,
55                     const TargetOptions &targetopts,
56                     const LangOptions &langopts, bool TimePasses,
57                     const std::string &infile, llvm::Module *LinkModule,
58                     raw_ostream *OS, LLVMContext &C)
59         : Diags(_Diags), Action(action), CodeGenOpts(compopts),
60           TargetOpts(targetopts), LangOpts(langopts), AsmOutStream(OS),
61           Context(), LLVMIRGeneration("LLVM IR Generation Time"),
62           Gen(CreateLLVMCodeGen(Diags, infile, compopts, targetopts, C)),
63           LinkModule(LinkModule) {
64       llvm::TimePassesIsEnabled = TimePasses;
65     }
66 
67     llvm::Module *takeModule() { return TheModule.take(); }
68     llvm::Module *takeLinkModule() { return LinkModule.take(); }
69 
70     virtual void HandleCXXStaticMemberVarInstantiation(VarDecl *VD) {
71       Gen->HandleCXXStaticMemberVarInstantiation(VD);
72     }
73 
74     virtual void Initialize(ASTContext &Ctx) {
75       Context = &Ctx;
76 
77       if (llvm::TimePassesIsEnabled)
78         LLVMIRGeneration.startTimer();
79 
80       Gen->Initialize(Ctx);
81 
82       TheModule.reset(Gen->GetModule());
83 
84       if (llvm::TimePassesIsEnabled)
85         LLVMIRGeneration.stopTimer();
86     }
87 
88     virtual bool HandleTopLevelDecl(DeclGroupRef D) {
89       PrettyStackTraceDecl CrashInfo(*D.begin(), SourceLocation(),
90                                      Context->getSourceManager(),
91                                      "LLVM IR generation of declaration");
92 
93       if (llvm::TimePassesIsEnabled)
94         LLVMIRGeneration.startTimer();
95 
96       Gen->HandleTopLevelDecl(D);
97 
98       if (llvm::TimePassesIsEnabled)
99         LLVMIRGeneration.stopTimer();
100 
101       return true;
102     }
103 
104     virtual void HandleTranslationUnit(ASTContext &C) {
105       {
106         PrettyStackTraceString CrashInfo("Per-file LLVM IR generation");
107         if (llvm::TimePassesIsEnabled)
108           LLVMIRGeneration.startTimer();
109 
110         Gen->HandleTranslationUnit(C);
111 
112         if (llvm::TimePassesIsEnabled)
113           LLVMIRGeneration.stopTimer();
114       }
115 
116       // Silently ignore if we weren't initialized for some reason.
117       if (!TheModule)
118         return;
119 
120       // Make sure IR generation is happy with the module. This is released by
121       // the module provider.
122       llvm::Module *M = Gen->ReleaseModule();
123       if (!M) {
124         // The module has been released by IR gen on failures, do not double
125         // free.
126         TheModule.take();
127         return;
128       }
129 
130       assert(TheModule.get() == M &&
131              "Unexpected module change during IR generation");
132 
133       // Link LinkModule into this module if present, preserving its validity.
134       if (LinkModule) {
135         std::string ErrorMsg;
136         if (Linker::LinkModules(M, LinkModule.get(), Linker::PreserveSource,
137                                 &ErrorMsg)) {
138           Diags.Report(diag::err_fe_cannot_link_module)
139             << LinkModule->getModuleIdentifier() << ErrorMsg;
140           return;
141         }
142       }
143 
144       // Install an inline asm handler so that diagnostics get printed through
145       // our diagnostics hooks.
146       LLVMContext &Ctx = TheModule->getContext();
147       LLVMContext::InlineAsmDiagHandlerTy OldHandler =
148         Ctx.getInlineAsmDiagnosticHandler();
149       void *OldContext = Ctx.getInlineAsmDiagnosticContext();
150       Ctx.setInlineAsmDiagnosticHandler(InlineAsmDiagHandler, this);
151 
152       EmitBackendOutput(Diags, CodeGenOpts, TargetOpts, LangOpts,
153                         TheModule.get(), Action, AsmOutStream);
154 
155       Ctx.setInlineAsmDiagnosticHandler(OldHandler, OldContext);
156     }
157 
158     virtual void HandleTagDeclDefinition(TagDecl *D) {
159       PrettyStackTraceDecl CrashInfo(D, SourceLocation(),
160                                      Context->getSourceManager(),
161                                      "LLVM IR generation of declaration");
162       Gen->HandleTagDeclDefinition(D);
163     }
164 
165     virtual void HandleTagDeclRequiredDefinition(const TagDecl *D) {
166       Gen->HandleTagDeclRequiredDefinition(D);
167     }
168 
169     virtual void CompleteTentativeDefinition(VarDecl *D) {
170       Gen->CompleteTentativeDefinition(D);
171     }
172 
173     virtual void HandleVTable(CXXRecordDecl *RD, bool DefinitionRequired) {
174       Gen->HandleVTable(RD, DefinitionRequired);
175     }
176 
177     virtual void HandleLinkerOptionPragma(llvm::StringRef Opts) {
178       Gen->HandleLinkerOptionPragma(Opts);
179     }
180 
181     virtual void HandleDetectMismatch(llvm::StringRef Name,
182                                       llvm::StringRef Value) {
183       Gen->HandleDetectMismatch(Name, Value);
184     }
185 
186     virtual void HandleDependentLibrary(llvm::StringRef Opts) {
187       Gen->HandleDependentLibrary(Opts);
188     }
189 
190     static void InlineAsmDiagHandler(const llvm::SMDiagnostic &SM,void *Context,
191                                      unsigned LocCookie) {
192       SourceLocation Loc = SourceLocation::getFromRawEncoding(LocCookie);
193       ((BackendConsumer*)Context)->InlineAsmDiagHandler2(SM, Loc);
194     }
195 
196     void InlineAsmDiagHandler2(const llvm::SMDiagnostic &,
197                                SourceLocation LocCookie);
198   };
199 
200   void BackendConsumer::anchor() {}
201 }
202 
203 /// ConvertBackendLocation - Convert a location in a temporary llvm::SourceMgr
204 /// buffer to be a valid FullSourceLoc.
205 static FullSourceLoc ConvertBackendLocation(const llvm::SMDiagnostic &D,
206                                             SourceManager &CSM) {
207   // Get both the clang and llvm source managers.  The location is relative to
208   // a memory buffer that the LLVM Source Manager is handling, we need to add
209   // a copy to the Clang source manager.
210   const llvm::SourceMgr &LSM = *D.getSourceMgr();
211 
212   // We need to copy the underlying LLVM memory buffer because llvm::SourceMgr
213   // already owns its one and clang::SourceManager wants to own its one.
214   const MemoryBuffer *LBuf =
215   LSM.getMemoryBuffer(LSM.FindBufferContainingLoc(D.getLoc()));
216 
217   // Create the copy and transfer ownership to clang::SourceManager.
218   llvm::MemoryBuffer *CBuf =
219   llvm::MemoryBuffer::getMemBufferCopy(LBuf->getBuffer(),
220                                        LBuf->getBufferIdentifier());
221   FileID FID = CSM.createFileIDForMemBuffer(CBuf);
222 
223   // Translate the offset into the file.
224   unsigned Offset = D.getLoc().getPointer()  - LBuf->getBufferStart();
225   SourceLocation NewLoc =
226   CSM.getLocForStartOfFile(FID).getLocWithOffset(Offset);
227   return FullSourceLoc(NewLoc, CSM);
228 }
229 
230 
231 /// InlineAsmDiagHandler2 - This function is invoked when the backend hits an
232 /// error parsing inline asm.  The SMDiagnostic indicates the error relative to
233 /// the temporary memory buffer that the inline asm parser has set up.
234 void BackendConsumer::InlineAsmDiagHandler2(const llvm::SMDiagnostic &D,
235                                             SourceLocation LocCookie) {
236   // There are a couple of different kinds of errors we could get here.  First,
237   // we re-format the SMDiagnostic in terms of a clang diagnostic.
238 
239   // Strip "error: " off the start of the message string.
240   StringRef Message = D.getMessage();
241   if (Message.startswith("error: "))
242     Message = Message.substr(7);
243 
244   // If the SMDiagnostic has an inline asm source location, translate it.
245   FullSourceLoc Loc;
246   if (D.getLoc() != SMLoc())
247     Loc = ConvertBackendLocation(D, Context->getSourceManager());
248 
249 
250   // If this problem has clang-level source location information, report the
251   // issue as being an error in the source with a note showing the instantiated
252   // code.
253   if (LocCookie.isValid()) {
254     Diags.Report(LocCookie, diag::err_fe_inline_asm).AddString(Message);
255 
256     if (D.getLoc().isValid()) {
257       DiagnosticBuilder B = Diags.Report(Loc, diag::note_fe_inline_asm_here);
258       // Convert the SMDiagnostic ranges into SourceRange and attach them
259       // to the diagnostic.
260       for (unsigned i = 0, e = D.getRanges().size(); i != e; ++i) {
261         std::pair<unsigned, unsigned> Range = D.getRanges()[i];
262         unsigned Column = D.getColumnNo();
263         B << SourceRange(Loc.getLocWithOffset(Range.first - Column),
264                          Loc.getLocWithOffset(Range.second - Column));
265       }
266     }
267     return;
268   }
269 
270   // Otherwise, report the backend error as occurring in the generated .s file.
271   // If Loc is invalid, we still need to report the error, it just gets no
272   // location info.
273   Diags.Report(Loc, diag::err_fe_inline_asm).AddString(Message);
274 }
275 
276 //
277 
278 CodeGenAction::CodeGenAction(unsigned _Act, LLVMContext *_VMContext)
279   : Act(_Act), LinkModule(0),
280     VMContext(_VMContext ? _VMContext : new LLVMContext),
281     OwnsVMContext(!_VMContext) {}
282 
283 CodeGenAction::~CodeGenAction() {
284   TheModule.reset();
285   if (OwnsVMContext)
286     delete VMContext;
287 }
288 
289 bool CodeGenAction::hasIRSupport() const { return true; }
290 
291 void CodeGenAction::EndSourceFileAction() {
292   // If the consumer creation failed, do nothing.
293   if (!getCompilerInstance().hasASTConsumer())
294     return;
295 
296   // If we were given a link module, release consumer's ownership of it.
297   if (LinkModule)
298     BEConsumer->takeLinkModule();
299 
300   // Steal the module from the consumer.
301   TheModule.reset(BEConsumer->takeModule());
302 }
303 
304 llvm::Module *CodeGenAction::takeModule() {
305   return TheModule.take();
306 }
307 
308 llvm::LLVMContext *CodeGenAction::takeLLVMContext() {
309   OwnsVMContext = false;
310   return VMContext;
311 }
312 
313 static raw_ostream *GetOutputStream(CompilerInstance &CI,
314                                     StringRef InFile,
315                                     BackendAction Action) {
316   switch (Action) {
317   case Backend_EmitAssembly:
318     return CI.createDefaultOutputFile(false, InFile, "s");
319   case Backend_EmitLL:
320     return CI.createDefaultOutputFile(false, InFile, "ll");
321   case Backend_EmitBC:
322     return CI.createDefaultOutputFile(true, InFile, "bc");
323   case Backend_EmitNothing:
324     return 0;
325   case Backend_EmitMCNull:
326   case Backend_EmitObj:
327     return CI.createDefaultOutputFile(true, InFile, "o");
328   }
329 
330   llvm_unreachable("Invalid action!");
331 }
332 
333 ASTConsumer *CodeGenAction::CreateASTConsumer(CompilerInstance &CI,
334                                               StringRef InFile) {
335   BackendAction BA = static_cast<BackendAction>(Act);
336   OwningPtr<raw_ostream> OS(GetOutputStream(CI, InFile, BA));
337   if (BA != Backend_EmitNothing && !OS)
338     return 0;
339 
340   llvm::Module *LinkModuleToUse = LinkModule;
341 
342   // If we were not given a link module, and the user requested that one be
343   // loaded from bitcode, do so now.
344   const std::string &LinkBCFile = CI.getCodeGenOpts().LinkBitcodeFile;
345   if (!LinkModuleToUse && !LinkBCFile.empty()) {
346     std::string ErrorStr;
347 
348     llvm::MemoryBuffer *BCBuf =
349       CI.getFileManager().getBufferForFile(LinkBCFile, &ErrorStr);
350     if (!BCBuf) {
351       CI.getDiagnostics().Report(diag::err_cannot_open_file)
352         << LinkBCFile << ErrorStr;
353       return 0;
354     }
355 
356     LinkModuleToUse = getLazyBitcodeModule(BCBuf, *VMContext, &ErrorStr);
357     if (!LinkModuleToUse) {
358       CI.getDiagnostics().Report(diag::err_cannot_open_file)
359         << LinkBCFile << ErrorStr;
360       return 0;
361     }
362   }
363 
364   BEConsumer =
365       new BackendConsumer(BA, CI.getDiagnostics(),
366                           CI.getCodeGenOpts(), CI.getTargetOpts(),
367                           CI.getLangOpts(),
368                           CI.getFrontendOpts().ShowTimers, InFile,
369                           LinkModuleToUse, OS.take(), *VMContext);
370   return BEConsumer;
371 }
372 
373 void CodeGenAction::ExecuteAction() {
374   // If this is an IR file, we have to treat it specially.
375   if (getCurrentFileKind() == IK_LLVM_IR) {
376     BackendAction BA = static_cast<BackendAction>(Act);
377     CompilerInstance &CI = getCompilerInstance();
378     raw_ostream *OS = GetOutputStream(CI, getCurrentFile(), BA);
379     if (BA != Backend_EmitNothing && !OS)
380       return;
381 
382     bool Invalid;
383     SourceManager &SM = CI.getSourceManager();
384     const llvm::MemoryBuffer *MainFile = SM.getBuffer(SM.getMainFileID(),
385                                                       &Invalid);
386     if (Invalid)
387       return;
388 
389     // FIXME: This is stupid, IRReader shouldn't take ownership.
390     llvm::MemoryBuffer *MainFileCopy =
391       llvm::MemoryBuffer::getMemBufferCopy(MainFile->getBuffer(),
392                                            getCurrentFile());
393 
394     llvm::SMDiagnostic Err;
395     TheModule.reset(ParseIR(MainFileCopy, Err, *VMContext));
396     if (!TheModule) {
397       // Translate from the diagnostic info to the SourceManager location.
398       SourceLocation Loc = SM.translateFileLineCol(
399         SM.getFileEntryForID(SM.getMainFileID()), Err.getLineNo(),
400         Err.getColumnNo() + 1);
401 
402       // Get a custom diagnostic for the error. We strip off a leading
403       // diagnostic code if there is one.
404       StringRef Msg = Err.getMessage();
405       if (Msg.startswith("error: "))
406         Msg = Msg.substr(7);
407 
408       // Escape '%', which is interpreted as a format character.
409       SmallString<128> EscapedMessage;
410       for (unsigned i = 0, e = Msg.size(); i != e; ++i) {
411         if (Msg[i] == '%')
412           EscapedMessage += '%';
413         EscapedMessage += Msg[i];
414       }
415 
416       unsigned DiagID = CI.getDiagnostics().getCustomDiagID(
417           DiagnosticsEngine::Error, EscapedMessage);
418 
419       CI.getDiagnostics().Report(Loc, DiagID);
420       return;
421     }
422 
423     EmitBackendOutput(CI.getDiagnostics(), CI.getCodeGenOpts(),
424                       CI.getTargetOpts(), CI.getLangOpts(),
425                       TheModule.get(),
426                       BA, OS);
427     return;
428   }
429 
430   // Otherwise follow the normal AST path.
431   this->ASTFrontendAction::ExecuteAction();
432 }
433 
434 //
435 
436 void EmitAssemblyAction::anchor() { }
437 EmitAssemblyAction::EmitAssemblyAction(llvm::LLVMContext *_VMContext)
438   : CodeGenAction(Backend_EmitAssembly, _VMContext) {}
439 
440 void EmitBCAction::anchor() { }
441 EmitBCAction::EmitBCAction(llvm::LLVMContext *_VMContext)
442   : CodeGenAction(Backend_EmitBC, _VMContext) {}
443 
444 void EmitLLVMAction::anchor() { }
445 EmitLLVMAction::EmitLLVMAction(llvm::LLVMContext *_VMContext)
446   : CodeGenAction(Backend_EmitLL, _VMContext) {}
447 
448 void EmitLLVMOnlyAction::anchor() { }
449 EmitLLVMOnlyAction::EmitLLVMOnlyAction(llvm::LLVMContext *_VMContext)
450   : CodeGenAction(Backend_EmitNothing, _VMContext) {}
451 
452 void EmitCodeGenOnlyAction::anchor() { }
453 EmitCodeGenOnlyAction::EmitCodeGenOnlyAction(llvm::LLVMContext *_VMContext)
454   : CodeGenAction(Backend_EmitMCNull, _VMContext) {}
455 
456 void EmitObjAction::anchor() { }
457 EmitObjAction::EmitObjAction(llvm::LLVMContext *_VMContext)
458   : CodeGenAction(Backend_EmitObj, _VMContext) {}
459