[clang][codegen] Add F128 vsnprintf_chk builtin

[tbaeder]

Summary

Fixes https://github.com/llvm/llvm-project/issues/61913

[tuliom]

@tbaeder Keep in mind that I don't think this will completely fix issue 61913 because there are other 2 functions affected.
Otherwise, I believe this patch is in the right direction.

clang/lib/CodeGen/CGBuiltin.cpp

104

I believe this should be redirected to __vsnprintf_chkieee128.

clang/lib/CodeGen/CGBuiltin.cpp

llvm::Constant *CodeGenModule::getBuiltinLibFunction(const FunctionDecl *FD,
   // Get the name, skip over the __builtin_ prefix (if necessary).
   StringRef Name;
   GlobalDecl D(FD);
 
   // TODO: This list should be expanded or refactored after all GCC-compatible
   // std libcall builtins are implemented.
   static SmallDenseMap<unsigned, StringRef, 8> F128Builtins{
       {Builtin::BI__builtin_printf, "__printfieee128"},
+      {Builtin::BI__builtin___vsnprintf_chk, "__vsnprintfieee128"},
       {Builtin::BI__builtin_vsnprintf, "__vsnprintfieee128"},
       {Builtin::BI__builtin_vsprintf, "__vsprintfieee128"},
       {Builtin::BI__builtin_sprintf, "__sprintfieee128"},
       {Builtin::BI__builtin_snprintf, "__snprintfieee128"},
       {Builtin::BI__builtin_fprintf, "__fprintfieee128"},
       {Builtin::BI__builtin_nexttowardf128, "__nexttowardieee128"},
   };
 

clang/test/CodeGen/PowerPC/ppc64-f128-builtins.c

 // PPC128: call signext i32 @vsnprintf
 void test_vsnprintf(int n, ...) {
   __builtin_va_list va;
   __builtin_va_start(va, n);
   __builtin_vsnprintf(buf, 20, "%.Lf", va);
   __builtin_va_end(va);
 }
 
+// IEEE128-LABEL: define dso_local void @test_vsnprintf_chk
+// IEEE128: call signext i32 @__vsnprintfieee128
+// PPC128-LABEL: define dso_local void @test_vsnprintf_chk
+// PPC128: call signext i32 @__vsnprintf_chk
+void test_vsnprintf_chk(int n, ...) {
+  __builtin_va_list va;
+  __builtin_va_start(va, n);
+  __builtin___vsnprintf_chk(buf, 20, 0 , sizeof(buf), "%.Lf", va);
+  __builtin_va_end(va);
+}
+
 // IEEE128-LABEL: define dso_local void @test_vsprintf
 // IEEE128: call signext i32 @__vsprintfieee128
 // PPC128-LABEL: define dso_local void @test_vsprintf
 // PPC128: call signext i32 @vsprintf
 void test_vsprintf(int n, ...) {
   __builtin_va_list va;
   __builtin_va_start(va, n);
   __builtin_vsprintf(buf, "%.Lf", va);