[PATCH] D52920: Introduce code_model macros

[Fangrui Song via Phabricator via cfe-commits]

MaskRay added inline comments.


================
Comment at: include/clang/Basic/TargetOptions.h:72
+  // The code model to be used as specified by the user. Corresponds to
+  // Model enum defined in include/llvm/Support/CodeGen.h, plus "default" for
+  // the case when the user has not explicitly specified a code model.
----------------
`Model` -> `CodeModel::Model` because there are `Model` in other namespaces

```
  namespace Reloc {
  enum Model { Static, PIC_, DynamicNoPIC, ROPI, RWPI, ROPI_RWPI };
  }

  // Code model types.
  namespace CodeModel {
    // Sync changes with CodeGenCWrappers.h.
  enum Model { Tiny, Small, Kernel, Medium, Large };
  }
```


================
Comment at: lib/Basic/Targets/X86.cpp:866
+    // For compatibility with gcc.
+    CodeModel = "small";
+  Builder.defineMacro("__code_model_" + CodeModel + "_");
----------------
The comment `// For compatibility with gcc.` needs changing.

Small code model is the fastest and expected to be suitable for vast majority of programs.

It is chosen here:

https://github.com/llvm-mirror/llvm/tree/master/lib/Target/X86/X86TargetMachine.cpp#L208

static CodeModel::Model getEffectiveCodeModel(Optional<CodeModel::Model> CM,
                                              bool JIT, bool Is64Bit) {
  if (CM)
    return *CM;
  if (JIT)
    return Is64Bit ? CodeModel::Large : CodeModel::Small;
  return CodeModel::Small;
}



Repository:
  rC Clang

https://reviews.llvm.org/D52920