[llvm] [CFI] Fix Direct Call Issues in CFI Dispatch Table (PR #69663)

[Oskar Wirga via llvm-commits]

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@@ -1471,6 +1471,11 @@ void LowerTypeTestsModule::createJumpTable(
   SmallVector<Value *, 16> AsmArgs;
   AsmArgs.reserve(Functions.size() * 2);
 
+  // Check if the first entry has the NoUnwind attribute.
----------------
oskarwirga wrote:

I confirmed that with dispatch tables of size > 1 I do not see direct calls to the jump table for throwing functions: 
```llvm
define dso_local void @_Z10call_catchi(i32 noundef %num) local_unnamed_addr #3 personality ptr @__gxx_personality_v0 !type !4 !type !5 !type !6 {
entry:
  store ptr getelementptr inbounds ([2 x [8 x i8]], ptr @_Z8no_throwi.cfi_jt, i64 0, i64 1), ptr @catch_ptr, align 8, !tbaa !14
  invoke void getelementptr inbounds ([2 x [8 x i8]], ptr @_Z8no_throwi.cfi_jt, i64 0, i64 1)(i32 noundef %num) #8
          to label %try.cont unwind label %lpad

lpad:                                             ; preds = %entry
  %0 = landingpad { ptr, i32 }
          catch ptr @_ZTIi
  %1 = extractvalue { ptr, i32 } %0, 1
  %2 = tail call i32 @llvm.eh.typeid.for(ptr nonnull @_ZTIi) #10
  %matches = icmp eq i32 %1, %2
  br i1 %matches, label %catch, label %eh.resume

catch:                                            ; preds = %lpad
  %3 = extractvalue { ptr, i32 } %0, 0
  %4 = tail call ptr @__cxa_begin_catch(ptr %3) #10
  tail call void @__cxa_end_catch() #10
  br label %try.cont

try.cont:                                         ; preds = %catch, %entry
  ret void

eh.resume:                                        ; preds = %lpad
  resume { ptr, i32 } %0
}
```

https://github.com/llvm/llvm-project/pull/69663