Fix two (three) more issues with unchecked Error.

[srhines]

Summary

If assertions are disabled, but LLVM_ABI_BREAKING_CHANGES is enabled,
this will cause an issue with an unchecked Success. Switching to
consumeError() is the correct way to bypass the check. This patch also
includes disabling 2 tests that can't work without assertions enabled,
since llvm_unreachable() with NDEBUG won't crash.

[srhines]

https://reviews.llvm.org/D36728 is related for Clang (where this was discovered to crash clang-format in some configurations).

[srhines]

Switch to cantFail

[lhames]

include/llvm/ExecutionEngine/Orc/OrcRemoteTargetClient.h

171–174 ↗

(On Diff #111289)

Since we're not using the error we can avoid naming it at all and just have:

//FIXME: Add error poll.
cantFail(Client.deregisterEHFrames(Frame.Addr, Frame.Size));

[srhines]

Remove unnecessary variable and assertion.

[srhines]

PTAL

[srhines]

Ping.

[lhames]

LGTM. :)

llvm/trunk/include/llvm/ExecutionEngine/Orc/OrcRemoteTargetClient.h

public:
 
     void registerEHFrames(uint8_t *Addr, uint64_t LoadAddr,
                           size_t Size) override {
       UnfinalizedEHFrames.push_back({LoadAddr, Size});
     }
 
     void deregisterEHFrames() override {
       for (auto &Frame : RegisteredEHFrames) {
-        auto Err = Client.deregisterEHFrames(Frame.Addr, Frame.Size);
         // FIXME: Add error poll.
-        assert(!Err && "Failed to register remote EH frames.");
-        (void)Err;
+        llvm::cantFail(Client.deregisterEHFrames(Frame.Addr, Frame.Size));
       }
     }
 
     void notifyObjectLoaded(RuntimeDyld &Dyld,
                             const object::ObjectFile &Obj) override {
       DEBUG(dbgs() << "Allocator " << Id << " applied mappings:\n");
       for (auto &ObjAllocs : Unmapped) {
         {

llvm/trunk/unittests/Support/ErrorTest.cpp

TEST(Error, CantFailSuccess) {
   EXPECT_EQ(X, 42) << "Expected value modified by cantFail";
 
   int Dummy = 42;
   int &Y = cantFail(Expected<int&>(Dummy));
   EXPECT_EQ(&Dummy, &Y) << "Reference mangled by cantFail";
 }
 
 // Test that cantFail results in a crash if you pass it a failure value.
-#if LLVM_ENABLE_ABI_BREAKING_CHECKS
+#if LLVM_ENABLE_ABI_BREAKING_CHECKS && !defined(NDEBUG)
 TEST(Error, CantFailDeath) {
   EXPECT_DEATH(
       cantFail(make_error<StringError>("foo", inconvertibleErrorCode())),
       "Failure value returned from cantFail wrapped call")
     << "cantFail(Error) did not cause an abort for failure value";
 
   EXPECT_DEATH(
       {