Break Frontend's dependency on Rewrite, Checker and CodeGen in shared library configuration

Currently, all AST consumers are located in the Frontend library,
meaning that in a shared library configuration, Frontend has a
dependency on Rewrite, Checker and CodeGen.  This is suboptimal for
clients which only wish to make use of the frontend.  CodeGen in
particular introduces a large number of unwanted dependencies.

This patch breaks the dependency by moving all AST consumers with
dependencies on Rewrite, Checker and/or CodeGen to their respective
libraries.  The patch therefore introduces dependencies in the other
direction (i.e. from Rewrite, Checker and CodeGen to Frontend).

After applying this patch, Clang builds correctly using CMake and
shared libraries ("cmake -DBUILD_SHARED_LIBS=ON").

N.B. This patch includes file renames which are indicated in the
patch body.

Changes in this revision of the patch:
 - Fixed some copy-paste mistakes in the header files
 - Modified certain aspects of the coding to comply with the LLVM
   Coding Standards

llvm-svn: 106010

1 files changed, 325 insertions, 0 deletions

diff --git a/clang/lib/CodeGen/BackendUtil.cpp b/clang/lib/CodeGen/BackendUtil.cpp
new file mode 100644
index 00000000000..766b239c4c0
--- /dev/null
+++ b/clang/lib/CodeGen/BackendUtil.cpp
@@ -0,0 +1,325 @@
+//===--- BackendUtil.cpp - LLVM Backend Utilities -------------------------===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+
+#include "clang/CodeGen/BackendUtil.h"
+#include "clang/Basic/Diagnostic.h"
+#include "clang/Basic/TargetOptions.h"
+#include "clang/CodeGen/CodeGenOptions.h"
+#include "clang/Frontend/FrontendDiagnostic.h"
+#include "llvm/Module.h"
+#include "llvm/PassManager.h"
+#include "llvm/Assembly/PrintModulePass.h"
+#include "llvm/Bitcode/ReaderWriter.h"
+#include "llvm/CodeGen/RegAllocRegistry.h"
+#include "llvm/CodeGen/SchedulerRegistry.h"
+#include "llvm/Support/CommandLine.h"
+#include "llvm/Support/FormattedStream.h"
+#include "llvm/Support/PrettyStackTrace.h"
+#include "llvm/Support/StandardPasses.h"
+#include "llvm/Support/Timer.h"
+#include "llvm/Support/raw_ostream.h"
+#include "llvm/Target/SubtargetFeature.h"
+#include "llvm/Target/TargetData.h"
+#include "llvm/Target/TargetMachine.h"
+#include "llvm/Target/TargetOptions.h"
+#include "llvm/Target/TargetRegistry.h"
+using namespace clang;
+using namespace llvm;
+
+namespace {
+
+class EmitAssemblyHelper {
+  Diagnostic &Diags;
+  const CodeGenOptions &CodeGenOpts;
+  const TargetOptions &TargetOpts;
+  Module *TheModule;
+
+  Timer CodeGenerationTime;
+
+  mutable FunctionPassManager *CodeGenPasses;
+  mutable PassManager *PerModulePasses;
+  mutable FunctionPassManager *PerFunctionPasses;
+
+private:
+  FunctionPassManager *getCodeGenPasses() const {
+    if (!CodeGenPasses) {
+      CodeGenPasses = new FunctionPassManager(TheModule);
+      CodeGenPasses->add(new TargetData(TheModule));
+    }
+    return CodeGenPasses;
+  }
+
+  PassManager *getPerModulePasses() const {
+    if (!PerModulePasses) {
+      PerModulePasses = new PassManager();
+      PerModulePasses->add(new TargetData(TheModule));
+    }
+    return PerModulePasses;
+  }
+
+  FunctionPassManager *getPerFunctionPasses() const {
+    if (!PerFunctionPasses) {
+      PerFunctionPasses = new FunctionPassManager(TheModule);
+      PerFunctionPasses->add(new TargetData(TheModule));
+    }
+    return PerFunctionPasses;
+  }
+
+  void CreatePasses();
+
+  /// AddEmitPasses - Add passes necessary to emit assembly or LLVM IR.
+  ///
+  /// \return True on success.
+  bool AddEmitPasses(BackendAction Action, formatted_raw_ostream &OS);
+
+public:
+  EmitAssemblyHelper(Diagnostic &_Diags,
+                     const CodeGenOptions &CGOpts, const TargetOptions &TOpts,
+                     Module *M)
+    : Diags(_Diags), CodeGenOpts(CGOpts), TargetOpts(TOpts),
+      TheModule(M), CodeGenerationTime("Code Generation Time"),
+      CodeGenPasses(0), PerModulePasses(0), PerFunctionPasses(0) {}
+
+  ~EmitAssemblyHelper() {
+    delete CodeGenPasses;
+    delete PerModulePasses;
+    delete PerFunctionPasses;
+  }
+
+  void EmitAssembly(BackendAction Action, raw_ostream *OS);
+};
+
+}
+
+void EmitAssemblyHelper::CreatePasses() {
+  unsigned OptLevel = CodeGenOpts.OptimizationLevel;
+  CodeGenOptions::InliningMethod Inlining = CodeGenOpts.Inlining;
+
+  // Handle disabling of LLVM optimization, where we want to preserve the
+  // internal module before any optimization.
+  if (CodeGenOpts.DisableLLVMOpts) {
+    OptLevel = 0;
+    Inlining = CodeGenOpts.NoInlining;
+  }
+
+  // In -O0 if checking is disabled, we don't even have per-function passes.
+  if (CodeGenOpts.VerifyModule)
+    getPerFunctionPasses()->add(createVerifierPass());
+
+  // Assume that standard function passes aren't run for -O0.
+  if (OptLevel > 0)
+    llvm::createStandardFunctionPasses(getPerFunctionPasses(), OptLevel);
+
+  llvm::Pass *InliningPass = 0;
+  switch (Inlining) {
+  case CodeGenOptions::NoInlining: break;
+  case CodeGenOptions::NormalInlining: {
+    // Set the inline threshold following llvm-gcc.
+    //
+    // FIXME: Derive these constants in a principled fashion.
+    unsigned Threshold = 225;
+    if (CodeGenOpts.OptimizeSize)
+      Threshold = 75;
+    else if (OptLevel > 2)
+      Threshold = 275;
+    InliningPass = createFunctionInliningPass(Threshold);
+    break;
+  }
+  case CodeGenOptions::OnlyAlwaysInlining:
+    InliningPass = createAlwaysInlinerPass();         // Respect always_inline
+    break;
+  }
+
+  // For now we always create per module passes.
+  llvm::createStandardModulePasses(getPerModulePasses(), OptLevel,
+                                   CodeGenOpts.OptimizeSize,
+                                   CodeGenOpts.UnitAtATime,
+                                   CodeGenOpts.UnrollLoops,
+                                   CodeGenOpts.SimplifyLibCalls,
+                                   /*HaveExceptions=*/true,
+                                   InliningPass);
+}
+
+bool EmitAssemblyHelper::AddEmitPasses(BackendAction Action,
+                                       formatted_raw_ostream &OS) {
+  // Create the TargetMachine for generating code.
+  std::string Error;
+  std::string Triple = TheModule->getTargetTriple();
+  const llvm::Target *TheTarget = TargetRegistry::lookupTarget(Triple, Error);
+  if (!TheTarget) {
+    Diags.Report(diag::err_fe_unable_to_create_target) << Error;
+    return false;
+  }
+
+  // FIXME: Expose these capabilities via actual APIs!!!! Aside from just
+  // being gross, this is also totally broken if we ever care about
+  // concurrency.
+  llvm::NoFramePointerElim = CodeGenOpts.DisableFPElim;
+  if (CodeGenOpts.FloatABI == "soft")
+    llvm::FloatABIType = llvm::FloatABI::Soft;
+  else if (CodeGenOpts.FloatABI == "hard")
+    llvm::FloatABIType = llvm::FloatABI::Hard;
+  else {
+    assert(CodeGenOpts.FloatABI.empty() && "Invalid float abi!");
+    llvm::FloatABIType = llvm::FloatABI::Default;
+  }
+  NoZerosInBSS = CodeGenOpts.NoZeroInitializedInBSS;
+  llvm::UseSoftFloat = CodeGenOpts.SoftFloat;
+  UnwindTablesMandatory = CodeGenOpts.UnwindTables;
+
+  TargetMachine::setAsmVerbosityDefault(CodeGenOpts.AsmVerbose);
+
+  TargetMachine::setFunctionSections(CodeGenOpts.FunctionSections);
+  TargetMachine::setDataSections    (CodeGenOpts.DataSections);
+
+  // FIXME: Parse this earlier.
+  if (CodeGenOpts.RelocationModel == "static") {
+    TargetMachine::setRelocationModel(llvm::Reloc::Static);
+  } else if (CodeGenOpts.RelocationModel == "pic") {
+    TargetMachine::setRelocationModel(llvm::Reloc::PIC_);
+  } else {
+    assert(CodeGenOpts.RelocationModel == "dynamic-no-pic" &&
+           "Invalid PIC model!");
+    TargetMachine::setRelocationModel(llvm::Reloc::DynamicNoPIC);
+  }
+  // FIXME: Parse this earlier.
+  if (CodeGenOpts.CodeModel == "small") {
+    TargetMachine::setCodeModel(llvm::CodeModel::Small);
+  } else if (CodeGenOpts.CodeModel == "kernel") {
+    TargetMachine::setCodeModel(llvm::CodeModel::Kernel);
+  } else if (CodeGenOpts.CodeModel == "medium") {
+    TargetMachine::setCodeModel(llvm::CodeModel::Medium);
+  } else if (CodeGenOpts.CodeModel == "large") {
+    TargetMachine::setCodeModel(llvm::CodeModel::Large);
+  } else {
+    assert(CodeGenOpts.CodeModel.empty() && "Invalid code model!");
+    TargetMachine::setCodeModel(llvm::CodeModel::Default);
+  }
+
+  std::vector<const char *> BackendArgs;
+  BackendArgs.push_back("clang"); // Fake program name.
+  if (!CodeGenOpts.DebugPass.empty()) {
+    BackendArgs.push_back("-debug-pass");
+    BackendArgs.push_back(CodeGenOpts.DebugPass.c_str());
+  }
+  if (!CodeGenOpts.LimitFloatPrecision.empty()) {
+    BackendArgs.push_back("-limit-float-precision");
+    BackendArgs.push_back(CodeGenOpts.LimitFloatPrecision.c_str());
+  }
+  if (llvm::TimePassesIsEnabled)
+    BackendArgs.push_back("-time-passes");
+  BackendArgs.push_back(0);
+  llvm::cl::ParseCommandLineOptions(BackendArgs.size() - 1,
+                                    const_cast<char **>(&BackendArgs[0]));
+
+  std::string FeaturesStr;
+  if (TargetOpts.CPU.size() || TargetOpts.Features.size()) {
+    SubtargetFeatures Features;
+    Features.setCPU(TargetOpts.CPU);
+    for (std::vector<std::string>::const_iterator
+           it = TargetOpts.Features.begin(),
+           ie = TargetOpts.Features.end(); it != ie; ++it)
+      Features.AddFeature(*it);
+    FeaturesStr = Features.getString();
+  }
+  TargetMachine *TM = TheTarget->createTargetMachine(Triple, FeaturesStr);
+
+  if (CodeGenOpts.RelaxAll)
+    TM->setMCRelaxAll(true);
+
+  // Create the code generator passes.
+  FunctionPassManager *PM = getCodeGenPasses();
+  CodeGenOpt::Level OptLevel = CodeGenOpt::Default;
+
+  switch (CodeGenOpts.OptimizationLevel) {
+  default: break;
+  case 0: OptLevel = CodeGenOpt::None; break;
+  case 3: OptLevel = CodeGenOpt::Aggressive; break;
+  }
+
+  // Normal mode, emit a .s or .o file by running the code generator. Note,
+  // this also adds codegenerator level optimization passes.
+  TargetMachine::CodeGenFileType CGFT = TargetMachine::CGFT_AssemblyFile;
+  if (Action == Backend_EmitObj)
+    CGFT = TargetMachine::CGFT_ObjectFile;
+  else if (Action == Backend_EmitMCNull)
+    CGFT = TargetMachine::CGFT_Null;
+  else
+    assert(Action == Backend_EmitAssembly && "Invalid action!");
+  if (TM->addPassesToEmitFile(*PM, OS, CGFT, OptLevel,
+                              /*DisableVerify=*/!CodeGenOpts.VerifyModule)) {
+    Diags.Report(diag::err_fe_unable_to_interface_with_target);
+    return false;
+  }
+
+  return true;
+}
+
+void EmitAssemblyHelper::EmitAssembly(BackendAction Action, raw_ostream *OS) {
+  TimeRegion Region(llvm::TimePassesIsEnabled ? &CodeGenerationTime : 0);
+  llvm::formatted_raw_ostream FormattedOS;
+
+  CreatePasses();
+  switch (Action) {
+  case Backend_EmitNothing:
+    break;
+
+  case Backend_EmitBC:
+    getPerModulePasses()->add(createBitcodeWriterPass(*OS));
+    break;
+
+  case Backend_EmitLL:
+    FormattedOS.setStream(*OS, formatted_raw_ostream::PRESERVE_STREAM);
+    getPerModulePasses()->add(createPrintModulePass(&FormattedOS));
+    break;
+
+  default:
+    FormattedOS.setStream(*OS, formatted_raw_ostream::PRESERVE_STREAM);
+    if (!AddEmitPasses(Action, FormattedOS))
+      return;
+  }
+
+  // Run passes. For now we do all passes at once, but eventually we
+  // would like to have the option of streaming code generation.
+
+  if (PerFunctionPasses) {
+    PrettyStackTraceString CrashInfo("Per-function optimization");
+
+    PerFunctionPasses->doInitialization();
+    for (Module::iterator I = TheModule->begin(),
+           E = TheModule->end(); I != E; ++I)
+      if (!I->isDeclaration())
+        PerFunctionPasses->run(*I);
+    PerFunctionPasses->doFinalization();
+  }
+
+  if (PerModulePasses) {
+    PrettyStackTraceString CrashInfo("Per-module optimization passes");
+    PerModulePasses->run(*TheModule);
+  }
+
+  if (CodeGenPasses) {
+    PrettyStackTraceString CrashInfo("Code generation");
+
+    CodeGenPasses->doInitialization();
+    for (Module::iterator I = TheModule->begin(),
+           E = TheModule->end(); I != E; ++I)
+      if (!I->isDeclaration())
+        CodeGenPasses->run(*I);
+    CodeGenPasses->doFinalization();
+  }
+}
+
+void clang::EmitBackendOutput(Diagnostic &Diags, const CodeGenOptions &CGOpts,
+                              const TargetOptions &TOpts, Module *M,
+                              BackendAction Action, raw_ostream *OS) {
+  EmitAssemblyHelper AsmHelper(Diags, CGOpts, TOpts, M);
+
+  AsmHelper.EmitAssembly(Action, OS);
+}