Toolchain: Normalize dwarf, sjlj and seh eh

adds -fseh-exceptions and -fdwarf-exceptions flags

clang will check if the user has specified an exception model flag,
in the absense of specifying the exception model clang will then check
the driver default and append the model flag for that target to cc1

clang cc1 assumes dwarf is the default if none is passed
and -fno-exceptions has a higher priority then specifying the model

move __SEH__ macro definitions out of Targets into InitPreprocessor
behind the -fseh-exceptions flag

move __ARM_DWARF_EH__ macrodefinitions out of verious targets and into
InitPreprocessor behind the -fdwarf-exceptions flag and arm|thumb check

remove unused USESEHExceptions from the MinGW Driver

fold USESjLjExceptions into a new GetExceptionModel function that
gives the toolchain classes more flexibility with eh models

Reviewers: rnk, mstorsjo

Differential Revision: https://reviews.llvm.org/D39673

llvm-svn: 319294

18 files changed, 104 insertions, 59 deletions

diff --git a/clang/lib/Basic/Targets/ARM.cpp b/clang/lib/Basic/Targets/ARM.cpp
index 77b3f9a5373..fe261b77485 100644
--- a/clang/lib/Basic/Targets/ARM.cpp
+++ b/clang/lib/Basic/Targets/ARM.cpp
@@ -1000,7 +1000,6 @@ void MinGWARMTargetInfo::getTargetDefines(const LangOptions &Opts,
                                           MacroBuilder &Builder) const {
   WindowsARMTargetInfo::getTargetDefines(Opts, Builder);
   Builder.defineMacro("_ARM_");
-  Builder.defineMacro("__ARM_DWARF_EH__");
 }
 
 CygwinARMTargetInfo::CygwinARMTargetInfo(const llvm::Triple &Triple,
diff --git a/clang/lib/Basic/Targets/OSTargets.cpp b/clang/lib/Basic/Targets/OSTargets.cpp
index b01e682e64d..50abd4ce0c8 100644
--- a/clang/lib/Basic/Targets/OSTargets.cpp
+++ b/clang/lib/Basic/Targets/OSTargets.cpp
@@ -133,10 +133,6 @@ void getDarwinDefines(MacroBuilder &Builder, const LangOptions &Opts,
   if (Triple.isOSDarwin())
     Builder.defineMacro("__MACH__");
 
-  // The Watch ABI uses Dwarf EH.
-  if (Triple.isWatchABI())
-    Builder.defineMacro("__ARM_DWARF_EH__");
-
   PlatformMinVersion = VersionTuple(Maj, Min, Rev);
 }
 } // namespace targets
diff --git a/clang/lib/Basic/Targets/OSTargets.h b/clang/lib/Basic/Targets/OSTargets.h
index cf2905fbb02..d6c64b90a84 100644
--- a/clang/lib/Basic/Targets/OSTargets.h
+++ b/clang/lib/Basic/Targets/OSTargets.h
@@ -358,17 +358,6 @@ protected:
     Builder.defineMacro("__ELF__");
     if (Opts.POSIXThreads)
       Builder.defineMacro("_REENTRANT");
-
-    switch (Triple.getArch()) {
-    default:
-      break;
-    case llvm::Triple::arm:
-    case llvm::Triple::armeb:
-    case llvm::Triple::thumb:
-    case llvm::Triple::thumbeb:
-      Builder.defineMacro("__ARM_DWARF_EH__");
-      break;
-    }
   }
 
 public:
diff --git a/clang/lib/Basic/Targets/X86.h b/clang/lib/Basic/Targets/X86.h
index 8f4f5dab6af..5a4b6b53b31 100644
--- a/clang/lib/Basic/Targets/X86.h
+++ b/clang/lib/Basic/Targets/X86.h
@@ -710,15 +710,6 @@ public:
     LongDoubleFormat = &llvm::APFloat::x87DoubleExtended();
     HasFloat128 = true;
   }
-
-  void getTargetDefines(const LangOptions &Opts,
-                        MacroBuilder &Builder) const override {
-    WindowsX86_64TargetInfo::getTargetDefines(Opts, Builder);
-
-    // GCC defines this macro when it is using __gxx_personality_seh0.
-    if (!Opts.SjLjExceptions)
-      Builder.defineMacro("__SEH__");
-  }
 };
 
 // x86-64 Cygwin target
@@ -740,10 +731,6 @@ public:
     DefineStd(Builder, "unix", Opts);
     if (Opts.CPlusPlus)
       Builder.defineMacro("_GNU_SOURCE");
-
-    // GCC defines this macro when it is using __gxx_personality_seh0.
-    if (!Opts.SjLjExceptions)
-      Builder.defineMacro("__SEH__");
   }
 };
 
diff --git a/clang/lib/CodeGen/BackendUtil.cpp b/clang/lib/CodeGen/BackendUtil.cpp
index 5a13f511afc..235ab2db52d 100644
--- a/clang/lib/CodeGen/BackendUtil.cpp
+++ b/clang/lib/CodeGen/BackendUtil.cpp
@@ -424,6 +424,10 @@ static void initTargetOptions(llvm::TargetOptions &Options,
 
   if (LangOpts.SjLjExceptions)
     Options.ExceptionModel = llvm::ExceptionHandling::SjLj;
+  if (LangOpts.SEHExceptions)
+    Options.ExceptionModel = llvm::ExceptionHandling::WinEH;
+  if (LangOpts.DWARFExceptions)
+    Options.ExceptionModel = llvm::ExceptionHandling::DwarfCFI;
 
   Options.NoInfsFPMath = CodeGenOpts.NoInfsFPMath;
   Options.NoNaNsFPMath = CodeGenOpts.NoNaNsFPMath;
diff --git a/clang/lib/CodeGen/CGException.cpp b/clang/lib/CodeGen/CGException.cpp
index 6a421e81dff..d6a9538bc1f 100644
--- a/clang/lib/CodeGen/CGException.cpp
+++ b/clang/lib/CodeGen/CGException.cpp
@@ -112,17 +112,11 @@ EHPersonality::MSVC_C_specific_handler = { "__C_specific_handler", nullptr };
 const EHPersonality
 EHPersonality::MSVC_CxxFrameHandler3 = { "__CxxFrameHandler3", nullptr };
 
-/// On Win64, use libgcc's SEH personality function. We fall back to dwarf on
-/// other platforms, unless the user asked for SjLj exceptions.
-static bool useLibGCCSEHPersonality(const llvm::Triple &T) {
-  return T.isOSWindows() && T.getArch() == llvm::Triple::x86_64;
-}
-
 static const EHPersonality &getCPersonality(const llvm::Triple &T,
                                             const LangOptions &L) {
   if (L.SjLjExceptions)
     return EHPersonality::GNU_C_SJLJ;
-  else if (useLibGCCSEHPersonality(T))
+  if (L.SEHExceptions)
     return EHPersonality::GNU_C_SEH;
   return EHPersonality::GNU_C;
 }
@@ -144,7 +138,7 @@ static const EHPersonality &getObjCPersonality(const llvm::Triple &T,
   case ObjCRuntime::ObjFW:
     if (L.SjLjExceptions)
       return EHPersonality::GNU_ObjC_SJLJ;
-    else if (useLibGCCSEHPersonality(T))
+    if (L.SEHExceptions)
       return EHPersonality::GNU_ObjC_SEH;
     return EHPersonality::GNU_ObjC;
   }
@@ -155,7 +149,7 @@ static const EHPersonality &getCXXPersonality(const llvm::Triple &T,
                                               const LangOptions &L) {
   if (L.SjLjExceptions)
     return EHPersonality::GNU_CPlusPlus_SJLJ;
-  else if (useLibGCCSEHPersonality(T))
+  if (L.SEHExceptions)
     return EHPersonality::GNU_CPlusPlus_SEH;
   return EHPersonality::GNU_CPlusPlus;
 }
@@ -211,6 +205,10 @@ const EHPersonality &EHPersonality::get(CodeGenModule &CGM,
   if (T.isWindowsMSVCEnvironment() && !L.ObjC1) {
     if (L.SjLjExceptions)
       return EHPersonality::GNU_CPlusPlus_SJLJ;
+    if (L.SEHExceptions)
+      return EHPersonality::GNU_CPlusPlus_SEH;
+    if (L.DWARFExceptions)
+      return EHPersonality::GNU_CPlusPlus;
     else
       return EHPersonality::MSVC_CxxFrameHandler3;
   }
diff --git a/clang/lib/Driver/ToolChain.cpp b/clang/lib/Driver/ToolChain.cpp
index 741f4284cbb..256fbf5ef2a 100644
--- a/clang/lib/Driver/ToolChain.cpp
+++ b/clang/lib/Driver/ToolChain.cpp
@@ -27,6 +27,8 @@
 #include "llvm/Support/ErrorHandling.h"
 #include "llvm/Support/FileSystem.h"
 #include "llvm/Support/Path.h"
+#include "llvm/MC/MCAsmInfo.h"
+#include "llvm/MC/MCRegisterInfo.h"
 #include "llvm/Support/TargetParser.h"
 #include "llvm/Support/TargetRegistry.h"
 
@@ -449,6 +451,13 @@ ObjCRuntime ToolChain::getDefaultObjCRuntime(bool isNonFragile) const {
                      VersionTuple());
 }
 
+llvm::ExceptionHandling
+ToolChain::GetExceptionModel(const llvm::opt::ArgList &Args) const {
+  if (Triple.isOSWindows())
+    return llvm::ExceptionHandling::WinEH;
+  return llvm::ExceptionHandling::None;
+}
+
 bool ToolChain::isThreadModelSupported(const StringRef Model) const {
   if (Model == "single") {
     // FIXME: 'single' is only supported on ARM and WebAssembly so far.
diff --git a/clang/lib/Driver/ToolChains/Clang.cpp b/clang/lib/Driver/ToolChains/Clang.cpp
index d96664cf0be..1c90c6e9225 100644
--- a/clang/lib/Driver/ToolChains/Clang.cpp
+++ b/clang/lib/Driver/ToolChains/Clang.cpp
@@ -4166,9 +4166,33 @@ void Clang::ConstructJob(Compilation &C, const JobAction &JA,
     addExceptionArgs(Args, InputType, getToolChain(), KernelOrKext, Runtime,
                      CmdArgs);
 
-  if (Args.hasArg(options::OPT_fsjlj_exceptions) ||
-      getToolChain().UseSjLjExceptions(Args))
-    CmdArgs.push_back("-fsjlj-exceptions");
+  // Handle exception personalities
+  Arg *A = Args.getLastArg(options::OPT_fsjlj_exceptions,
+                           options::OPT_fseh_exceptions,
+                           options::OPT_fdwarf_exceptions);
+  if (A) {
+    const Option &Opt = A->getOption();
+    if (Opt.matches(options::OPT_fsjlj_exceptions))
+      CmdArgs.push_back("-fsjlj-exceptions");
+    if (Opt.matches(options::OPT_fseh_exceptions))
+      CmdArgs.push_back("-fseh-exceptions");
+    if (Opt.matches(options::OPT_fdwarf_exceptions))
+      CmdArgs.push_back("-fdwarf-exceptions");
+  } else {
+    switch(getToolChain().GetExceptionModel(Args)) {
+      default:
+        break;
+      case llvm::ExceptionHandling::DwarfCFI:
+        CmdArgs.push_back("-fdwarf-exceptions");
+        break;
+      case llvm::ExceptionHandling::SjLj:
+        CmdArgs.push_back("-fsjlj-exceptions");
+        break;
+      case llvm::ExceptionHandling::WinEH:
+        CmdArgs.push_back("-fseh-exceptions");
+        break;
+    }
+  }
 
   // C++ "sane" operator new.
   if (!Args.hasFlag(options::OPT_fassume_sane_operator_new,
diff --git a/clang/lib/Driver/ToolChains/Darwin.cpp b/clang/lib/Driver/ToolChains/Darwin.cpp
index 5dc8a91bcf1..7c401aa9dd5 100644
--- a/clang/lib/Driver/ToolChains/Darwin.cpp
+++ b/clang/lib/Driver/ToolChains/Darwin.cpp
@@ -1881,7 +1881,7 @@ bool MachO::IsUnwindTablesDefault(const ArgList &Args) const {
   // Unwind tables are not emitted if -fno-exceptions is supplied (except when
   // targeting x86_64).
   return getArch() == llvm::Triple::x86_64 ||
-         (!UseSjLjExceptions(Args) &&
+         (GetExceptionModel(Args) != llvm::ExceptionHandling::SjLj &&
           Args.hasFlag(options::OPT_fexceptions, options::OPT_fno_exceptions,
                        true));
 }
@@ -1892,15 +1892,18 @@ bool MachO::UseDwarfDebugFlags() const {
   return false;
 }
 
-bool Darwin::UseSjLjExceptions(const ArgList &Args) const {
+llvm::ExceptionHandling Darwin::GetExceptionModel(const ArgList &Args) const {
   // Darwin uses SjLj exceptions on ARM.
   if (getTriple().getArch() != llvm::Triple::arm &&
       getTriple().getArch() != llvm::Triple::thumb)
-    return false;
+    return llvm::ExceptionHandling::None;
 
   // Only watchOS uses the new DWARF/Compact unwinding method.
   llvm::Triple Triple(ComputeLLVMTriple(Args));
-  return !Triple.isWatchABI();
+  if(Triple.isWatchABI())
+    return llvm::ExceptionHandling::DwarfCFI;
+
+  return llvm::ExceptionHandling::SjLj;
 }
 
 bool Darwin::SupportsEmbeddedBitcode() const {
diff --git a/clang/lib/Driver/ToolChains/Darwin.h b/clang/lib/Driver/ToolChains/Darwin.h
index 2b8477aa275..c861f172fe1 100644
--- a/clang/lib/Driver/ToolChains/Darwin.h
+++ b/clang/lib/Driver/ToolChains/Darwin.h
@@ -247,8 +247,9 @@ public:
 
   bool UseDwarfDebugFlags() const override;
 
-  bool UseSjLjExceptions(const llvm::opt::ArgList &Args) const override {
-    return false;
+  llvm::ExceptionHandling
+  GetExceptionModel(const llvm::opt::ArgList &Args) const override {
+    return llvm::ExceptionHandling::None;
   }
 
   /// }
@@ -455,7 +456,8 @@ public:
 
   void CheckObjCARC() const override;
 
-  bool UseSjLjExceptions(const llvm::opt::ArgList &Args) const override;
+  llvm::ExceptionHandling GetExceptionModel(
+      const llvm::opt::ArgList &Args) const override;
 
   bool SupportsEmbeddedBitcode() const override;
 
diff --git a/clang/lib/Driver/ToolChains/FreeBSD.cpp b/clang/lib/Driver/ToolChains/FreeBSD.cpp
index 2f066cf0cc8..025acf15117 100644
--- a/clang/lib/Driver/ToolChains/FreeBSD.cpp
+++ b/clang/lib/Driver/ToolChains/FreeBSD.cpp
@@ -359,17 +359,17 @@ Tool *FreeBSD::buildAssembler() const {
 
 Tool *FreeBSD::buildLinker() const { return new tools::freebsd::Linker(*this); }
 
-bool FreeBSD::UseSjLjExceptions(const ArgList &Args) const {
+llvm::ExceptionHandling FreeBSD::GetExceptionModel(const ArgList &Args) const {
   // FreeBSD uses SjLj exceptions on ARM oabi.
   switch (getTriple().getEnvironment()) {
+  default:
+    if (getTriple().getArch() == llvm::Triple::arm ||
+        getTriple().getArch() == llvm::Triple::thumb)
+      return llvm::ExceptionHandling::SjLj;
   case llvm::Triple::GNUEABIHF:
   case llvm::Triple::GNUEABI:
   case llvm::Triple::EABI:
-    return false;
-
-  default:
-    return (getTriple().getArch() == llvm::Triple::arm ||
-            getTriple().getArch() == llvm::Triple::thumb);
+    return llvm::ExceptionHandling::None;
   }
 }
 
diff --git a/clang/lib/Driver/ToolChains/FreeBSD.h b/clang/lib/Driver/ToolChains/FreeBSD.h
index 25e9df72bc8..2943e1cacfb 100644
--- a/clang/lib/Driver/ToolChains/FreeBSD.h
+++ b/clang/lib/Driver/ToolChains/FreeBSD.h
@@ -66,7 +66,8 @@ public:
   void AddCXXStdlibLibArgs(const llvm::opt::ArgList &Args,
                            llvm::opt::ArgStringList &CmdArgs) const override;
 
-  bool UseSjLjExceptions(const llvm::opt::ArgList &Args) const override;
+  llvm::ExceptionHandling GetExceptionModel(
+      const llvm::opt::ArgList &Args) const override;
   bool isPIEDefault() const override;
   SanitizerMask getSupportedSanitizers() const override;
   unsigned GetDefaultDwarfVersion() const override { return 2; }
diff --git a/clang/lib/Driver/ToolChains/MinGW.cpp b/clang/lib/Driver/ToolChains/MinGW.cpp
index 79864eab83e..572ea803f2d 100644
--- a/clang/lib/Driver/ToolChains/MinGW.cpp
+++ b/clang/lib/Driver/ToolChains/MinGW.cpp
@@ -367,8 +367,11 @@ bool toolchains::MinGW::isPICDefaultForced() const {
   return getArch() == llvm::Triple::x86_64;
 }
 
-bool toolchains::MinGW::UseSEHExceptions() const {
-  return getArch() == llvm::Triple::x86_64;
+llvm::ExceptionHandling
+toolchains::MinGW::GetExceptionModel(const ArgList &Args) const {
+  if (getArch() == llvm::Triple::x86_64)
+    return llvm::ExceptionHandling::WinEH;
+  return llvm::ExceptionHandling::DwarfCFI;
 }
 
 void toolchains::MinGW::AddCudaIncludeArgs(const ArgList &DriverArgs,
diff --git a/clang/lib/Driver/ToolChains/MinGW.h b/clang/lib/Driver/ToolChains/MinGW.h
index 9b3d7c553f1..f8dbcae6275 100644
--- a/clang/lib/Driver/ToolChains/MinGW.h
+++ b/clang/lib/Driver/ToolChains/MinGW.h
@@ -64,7 +64,9 @@ public:
   bool isPICDefault() const override;
   bool isPIEDefault() const override;
   bool isPICDefaultForced() const override;
-  bool UseSEHExceptions() const;
+
+  llvm::ExceptionHandling GetExceptionModel(
+      const llvm::opt::ArgList &Args) const override;
 
   void
   AddClangSystemIncludeArgs(const llvm::opt::ArgList &DriverArgs,
diff --git a/clang/lib/Driver/ToolChains/NetBSD.cpp b/clang/lib/Driver/ToolChains/NetBSD.cpp
index 85bb69cfda0..c0a0808b377 100644
--- a/clang/lib/Driver/ToolChains/NetBSD.cpp
+++ b/clang/lib/Driver/ToolChains/NetBSD.cpp
@@ -416,6 +416,14 @@ void NetBSD::addLibStdCxxIncludePaths(const llvm::opt::ArgList &DriverArgs,
                            "", DriverArgs, CC1Args);
 }
 
+llvm::ExceptionHandling NetBSD::GetExceptionModel(const ArgList &Args) const {
+  // NetBSD uses Dwarf exceptions on ARM.
+  if (getTriple().getArch() == llvm::Triple::arm ||
+      getTriple().getArch() == llvm::Triple::thumb)
+    return llvm::ExceptionHandling::DwarfCFI;
+  return llvm::ExceptionHandling::None;
+}
+
 SanitizerMask NetBSD::getSupportedSanitizers() const {
   const bool IsX86 = getTriple().getArch() == llvm::Triple::x86;
   const bool IsX86_64 = getTriple().getArch() == llvm::Triple::x86_64;
diff --git a/clang/lib/Driver/ToolChains/NetBSD.h b/clang/lib/Driver/ToolChains/NetBSD.h
index 5163ff72d81..e98df72ce65 100644
--- a/clang/lib/Driver/ToolChains/NetBSD.h
+++ b/clang/lib/Driver/ToolChains/NetBSD.h
@@ -69,6 +69,9 @@ public:
     return true;
   }
 
+  llvm::ExceptionHandling GetExceptionModel(
+      const llvm::opt::ArgList &Args) const override;
+
   SanitizerMask getSupportedSanitizers() const override;
 
 protected:
diff --git a/clang/lib/Frontend/CompilerInvocation.cpp b/clang/lib/Frontend/CompilerInvocation.cpp
index 3d484170f82..cdd53608f65 100644
--- a/clang/lib/Frontend/CompilerInvocation.cpp
+++ b/clang/lib/Frontend/CompilerInvocation.cpp
@@ -2141,7 +2141,18 @@ static void ParseLangArgs(LangOptions &Opts, ArgList &Args, InputKind IK,
   Opts.Exceptions = Args.hasArg(OPT_fexceptions);
   Opts.ObjCExceptions = Args.hasArg(OPT_fobjc_exceptions);
   Opts.CXXExceptions = Args.hasArg(OPT_fcxx_exceptions);
-  Opts.SjLjExceptions = Args.hasArg(OPT_fsjlj_exceptions);
+
+  // Handle exception personalities
+  Arg *A = Args.getLastArg(options::OPT_fsjlj_exceptions,
+                           options::OPT_fseh_exceptions,
+                           options::OPT_fdwarf_exceptions);
+  if (A) {
+    const Option &Opt = A->getOption();
+    Opts.SjLjExceptions = Opt.matches(options::OPT_fsjlj_exceptions);
+    Opts.SEHExceptions = Opt.matches(options::OPT_fseh_exceptions);
+    Opts.DWARFExceptions = Opt.matches(options::OPT_fdwarf_exceptions);
+  }
+
   Opts.ExternCNoUnwind = Args.hasArg(OPT_fexternc_nounwind);
   Opts.TraditionalCPP = Args.hasArg(OPT_traditional_cpp);
 
diff --git a/clang/lib/Frontend/InitPreprocessor.cpp b/clang/lib/Frontend/InitPreprocessor.cpp
index 1dfbf187554..67c1faddc3a 100644
--- a/clang/lib/Frontend/InitPreprocessor.cpp
+++ b/clang/lib/Frontend/InitPreprocessor.cpp
@@ -677,8 +677,14 @@ static void InitializePredefinedMacros(const TargetInfo &TI,
     Builder.defineMacro("__EXCEPTIONS");
   if (!LangOpts.MSVCCompat && LangOpts.RTTI)
     Builder.defineMacro("__GXX_RTTI");
+
   if (LangOpts.SjLjExceptions)
     Builder.defineMacro("__USING_SJLJ_EXCEPTIONS__");
+  else if (LangOpts.SEHExceptions)
+    Builder.defineMacro("__SEH__");
+  else if (LangOpts.DWARFExceptions &&
+          (TI.getTriple().isThumb() || TI.getTriple().isARM()))
+    Builder.defineMacro("__ARM_DWARF_EH__");
 
   if (LangOpts.Deprecated)
     Builder.defineMacro("__DEPRECATED");