Retry: [Driver] Compute effective target triples once per job (NFCI)

Compute an effective triple once per job. Cache the triple in the
prevailing ToolChain for the duration of the job.

Clients which need effective triples now look them up in the ToolChain.
This eliminates wasteful re-computation of effective triples (e.g in
getARMFloatABI()).

While we're at it, delete MachO::ComputeEffectiveClangTriple. It was a
no-op override.

Differential Revision: https://reviews.llvm.org/D22596

llvm-svn: 276937

clang/include/clang/Driver/ToolChain.h

@@ -40,6 +40,7 @@ namespace driver {
   class Compilation;
   class Driver;
   class JobAction;
+  class RegisterEffectiveTriple;
   class SanitizerArgs;
   class Tool;
 
@@ -91,6 +92,14 @@ class ToolChain {
 
   mutable std::unique_ptr<SanitizerArgs> SanitizerArguments;
 
+  /// The effective clang triple for the current Job.
+  mutable llvm::Triple EffectiveTriple;
+
+  /// Set the toolchain's effective clang triple.
+  void setEffectiveTriple(llvm::Triple ET) const { EffectiveTriple = ET; }
+
+  friend class RegisterEffectiveTriple;
+
 protected:
   MultilibSet Multilibs;
   const char *DefaultLinker = "ld";
@@ -141,6 +150,12 @@ class ToolChain {
     return Triple.getTriple();
   }
 
+  /// Get the toolchain's effective clang triple.
+  const llvm::Triple &getEffectiveTriple() const {
+    assert(!EffectiveTriple.getTriple().empty() && "No effective triple");
+    return EffectiveTriple;
+  }
+
   path_list &getFilePaths() { return FilePaths; }
   const path_list &getFilePaths() const { return FilePaths; }
 
@@ -432,6 +447,19 @@ class ToolChain {
   virtual VersionTuple getMSVCVersionFromExe() const { return VersionTuple(); }
 };
 
+/// Set a ToolChain's effective triple. Reset it when the registration object
+/// is destroyed.
+class RegisterEffectiveTriple {
+  const ToolChain &TC;
+
+public:
+  RegisterEffectiveTriple(const ToolChain &TC, llvm::Triple T) : TC(TC) {
+    TC.setEffectiveTriple(T);
+  }
+
+  ~RegisterEffectiveTriple() { TC.setEffectiveTriple(llvm::Triple()); }
+};
+
 } // end namespace driver
 } // end namespace clang
 

clang/lib/Driver/Driver.cpp

@@ -2247,6 +2247,19 @@ InputInfo Driver::BuildJobsForActionNoCache(
     InputInfos.append(OffloadDependencesInputInfo.begin(),
                       OffloadDependencesInputInfo.end());
 
+  // Set the effective triple of the toolchain for the duration of this job.
+  llvm::Triple EffectiveTriple;
+  const ToolChain &ToolTC = T->getToolChain();
+  const ArgList &Args = C.getArgsForToolChain(TC, BoundArch);
+  if (InputInfos.size() != 1) {
+    EffectiveTriple = llvm::Triple(ToolTC.ComputeEffectiveClangTriple(Args));
+  } else {
+    // Pass along the input type if it can be unambiguously determined.
+    EffectiveTriple = llvm::Triple(
+        ToolTC.ComputeEffectiveClangTriple(Args, InputInfos[0].getType()));
+  }
+  RegisterEffectiveTriple TripleRAII(ToolTC, EffectiveTriple);
+
   // Determine the place to write output to, if any.
   InputInfo Result;
   if (JA->getType() == types::TY_Nothing)

clang/lib/Driver/ToolChain.cpp

@@ -68,7 +68,8 @@ static ToolChain::RTTIMode CalculateRTTIMode(const ArgList &Args,
 ToolChain::ToolChain(const Driver &D, const llvm::Triple &T,
                      const ArgList &Args)
     : D(D), Triple(T), Args(Args), CachedRTTIArg(GetRTTIArgument(Args)),
-      CachedRTTIMode(CalculateRTTIMode(Args, Triple, CachedRTTIArg)) {
+      CachedRTTIMode(CalculateRTTIMode(Args, Triple, CachedRTTIArg)),
+      EffectiveTriple() {
   if (Arg *A = Args.getLastArg(options::OPT_mthread_model))
     if (!isThreadModelSupported(A->getValue()))
       D.Diag(diag::err_drv_invalid_thread_model_for_target)

clang/lib/Driver/ToolChains.cpp

@@ -176,13 +176,6 @@ Darwin::~Darwin() {}
 
 MachO::~MachO() {}
 
-std::string MachO::ComputeEffectiveClangTriple(const ArgList &Args,
-                                               types::ID InputType) const {
-  llvm::Triple Triple(ComputeLLVMTriple(Args, InputType));
-
-  return Triple.getTriple();
-}
-
 std::string Darwin::ComputeEffectiveClangTriple(const ArgList &Args,
                                                 types::ID InputType) const {
   llvm::Triple Triple(ComputeLLVMTriple(Args, InputType));

clang/lib/Driver/ToolChains.h

@@ -312,9 +312,6 @@ class LLVM_LIBRARY_VISIBILITY MachO : public ToolChain {
   /// @name ToolChain Implementation
   /// {
 
-  std::string ComputeEffectiveClangTriple(const llvm::opt::ArgList &Args,
-                                          types::ID InputType) const override;
-
   types::ID LookupTypeForExtension(const char *Ext) const override;
 
   bool HasNativeLLVMSupport() const override;

clang/lib/Driver/Tools.cpp

@@ -764,7 +764,7 @@ static bool useAAPCSForMachO(const llvm::Triple &T) {
 // -mfloat-abi=.
 arm::FloatABI arm::getARMFloatABI(const ToolChain &TC, const ArgList &Args) {
   const Driver &D = TC.getDriver();
-  const llvm::Triple Triple(TC.ComputeEffectiveClangTriple(Args));
+  const llvm::Triple &Triple = TC.getEffectiveTriple();
   auto SubArch = getARMSubArchVersionNumber(Triple);
   arm::FloatABI ABI = FloatABI::Invalid;
   if (Arg *A =
@@ -1165,8 +1165,7 @@ static std::string getAArch64TargetCPU(const ArgList &Args) {
 
 void Clang::AddAArch64TargetArgs(const ArgList &Args,
                                  ArgStringList &CmdArgs) const {
-  std::string TripleStr = getToolChain().ComputeEffectiveClangTriple(Args);
-  llvm::Triple Triple(TripleStr);
+  const llvm::Triple &Triple = getToolChain().getEffectiveTriple();
 
   if (!Args.hasFlag(options::OPT_mred_zone, options::OPT_mno_red_zone, true) ||
       Args.hasArg(options::OPT_mkernel) ||
@@ -3838,8 +3837,8 @@ static void AddAssemblerKPIC(const ToolChain &ToolChain, const ArgList &Args,
 void Clang::ConstructJob(Compilation &C, const JobAction &JA,
                          const InputInfo &Output, const InputInfoList &Inputs,
                          const ArgList &Args, const char *LinkingOutput) const {
-  std::string TripleStr = getToolChain().ComputeEffectiveClangTriple(Args);
-  const llvm::Triple Triple(TripleStr);
+  const llvm::Triple &Triple = getToolChain().getEffectiveTriple();
+  const std::string &TripleStr = Triple.getTriple();
 
   bool KernelOrKext =
       Args.hasArg(options::OPT_mkernel, options::OPT_fapple_kext);
@@ -6500,9 +6499,8 @@ void ClangAs::ConstructJob(Compilation &C, const JobAction &JA,
   assert(Inputs.size() == 1 && "Unexpected number of inputs.");
   const InputInfo &Input = Inputs[0];
 
-  std::string TripleStr =
-      getToolChain().ComputeEffectiveClangTriple(Args, Input.getType());
-  const llvm::Triple Triple(TripleStr);
+  const llvm::Triple &Triple = getToolChain().getEffectiveTriple();
+  const std::string &TripleStr = Triple.getTriple();
 
   // Don't warn about "clang -w -c foo.s"
   Args.ClaimAllArgs(options::OPT_w);
@@ -8878,9 +8876,7 @@ void netbsd::Linker::ConstructJob(Compilation &C, const JobAction &JA,
     break;
   case llvm::Triple::armeb:
   case llvm::Triple::thumbeb:
-    arm::appendEBLinkFlags(
-        Args, CmdArgs,
-        llvm::Triple(getToolChain().ComputeEffectiveClangTriple(Args)));
+    arm::appendEBLinkFlags(Args, CmdArgs, getToolChain().getEffectiveTriple());
     CmdArgs.push_back("-m");
     switch (getToolChain().getTriple().getEnvironment()) {
     case llvm::Triple::EABI:
@@ -9044,8 +9040,7 @@ void gnutools::Assembler::ConstructJob(Compilation &C, const JobAction &JA,
                                        const char *LinkingOutput) const {
   claimNoWarnArgs(Args);
 
-  std::string TripleStr = getToolChain().ComputeEffectiveClangTriple(Args);
-  llvm::Triple Triple = llvm::Triple(TripleStr);
+  const llvm::Triple &Triple = getToolChain().getEffectiveTriple();
 
   ArgStringList CmdArgs;
 
@@ -9380,8 +9375,7 @@ void gnutools::Linker::ConstructJob(Compilation &C, const JobAction &JA,
       static_cast<const toolchains::Linux &>(getToolChain());
   const Driver &D = ToolChain.getDriver();
 
-  std::string TripleStr = getToolChain().ComputeEffectiveClangTriple(Args);
-  llvm::Triple Triple = llvm::Triple(TripleStr);
+  const llvm::Triple &Triple = getToolChain().getEffectiveTriple();
 
   const llvm::Triple::ArchType Arch = ToolChain.getArch();
   const bool isAndroid = ToolChain.getTriple().isAndroid();