Enable EHABI by default

After all hard work to implement the EHABI and with the test-suite
passing, it's time to turn it on by default and allow users to
disable it as a work-around while we fix the eventual bugs that show
up.

This commit also remove the -arm-enable-ehabi-descriptors, since we
want the tables to be printed every time the EHABI is turned on
for non-Darwin ARM targets.

Although MCJIT EHABI is not working yet (needs linking with the right
libraries), this commit also fixes some relocations on MCJIT regarding
the EH tables/lib calls, and update some tests to avoid using EH tables
when none are needed.

The EH tests in the test-suite that were previously disabled on ARM
now pass with these changes, so a follow-up commit on the test-suite
will re-enable them.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@200388 91177308-0d34-0410-b5e6-96231b3b80d8

3 files changed, 18 insertions, 5 deletions

diff --git a/lib/Target/ARM/ARMAsmPrinter.cpp b/lib/Target/ARM/ARMAsmPrinter.cpp
index 9c40ac8a7a..46bd34fe39 100644
--- a/lib/Target/ARM/ARMAsmPrinter.cpp
+++ b/lib/Target/ARM/ARMAsmPrinter.cpp
@@ -1106,7 +1106,7 @@ void ARMAsmPrinter::EmitUnwindingInstruction(const MachineInstr *MI) {
   }
 }
 
-extern cl::opt<bool> EnableARMEHABI;
+extern cl::opt<bool> DisableARMEHABI;
 
 // Simple pseudo-instructions have their lowering (with expansion to real
 // instructions) auto-generated.
@@ -1122,7 +1122,8 @@ void ARMAsmPrinter::EmitInstruction(const MachineInstr *MI) {
   }
 
   // Emit unwinding stuff for frame-related instructions
-  if (EnableARMEHABI && MI->getFlag(MachineInstr::FrameSetup))
+  if (Subtarget->isTargetEHABICompatible() && !DisableARMEHABI &&
+       MI->getFlag(MachineInstr::FrameSetup))
     EmitUnwindingInstruction(MI);
 
   // Do any auto-generated pseudo lowerings.
diff --git a/lib/Target/ARM/ARMSubtarget.h b/lib/Target/ARM/ARMSubtarget.h
index 3a9f940381..200f198d27 100644
--- a/lib/Target/ARM/ARMSubtarget.h
+++ b/lib/Target/ARM/ARMSubtarget.h
@@ -328,6 +328,16 @@ public:
            !isTargetDarwin();
   }
 
+  // ARM Targets that support EHABI exception handling standard
+  // Darwin uses SjLj. Other targets might need more checks.
+  bool isTargetEHABICompatible() const {
+    return (TargetTriple.getEnvironment() == Triple::EABI ||
+            TargetTriple.getEnvironment() == Triple::GNUEABI ||
+            TargetTriple.getEnvironment() == Triple::EABIHF ||
+            TargetTriple.getEnvironment() == Triple::GNUEABIHF) &&
+           !isTargetDarwin();
+  }
+
   bool isTargetHardFloat() const {
     return TargetTriple.getEnvironment() == Triple::GNUEABIHF ||
            TargetTriple.getEnvironment() == Triple::EABIHF;
diff --git a/lib/Target/ARM/MCTargetDesc/ARMMCAsmInfo.cpp b/lib/Target/ARM/MCTargetDesc/ARMMCAsmInfo.cpp
index b2a71a8706..5cb6c0b44e 100644
--- a/lib/Target/ARM/MCTargetDesc/ARMMCAsmInfo.cpp
+++ b/lib/Target/ARM/MCTargetDesc/ARMMCAsmInfo.cpp
@@ -16,9 +16,11 @@
 
 using namespace llvm;
 
+// ARM EHABI is experimental but the quality is good enough
+// to be turned on by default on non-Darwin ARM targets.
 cl::opt<bool>
-EnableARMEHABI("arm-enable-ehabi", cl::Hidden,
-  cl::desc("Generate ARM EHABI tables"),
+DisableARMEHABI("arm-disable-ehabi", cl::Hidden,
+  cl::desc("Disable ARM experimental exception handling"),
   cl::init(false));
 
 
@@ -52,7 +54,7 @@ ARMELFMCAsmInfo::ARMELFMCAsmInfo() {
   SupportsDebugInformation = true;
 
   // Exceptions handling
-  if (EnableARMEHABI)
+  if (!DisableARMEHABI)
     ExceptionsType = ExceptionHandling::ARM;
 
   // foo(plt) instead of foo@plt