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

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@319294 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 7 insertions, 4 deletions

diff --git a/lib/Driver/ToolChains/Darwin.cpp b/lib/Driver/ToolChains/Darwin.cpp
index 5dc8a91bcf..7c401aa9dd 100644
--- a/lib/Driver/ToolChains/Darwin.cpp
+++ b/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 {