[PATCH] D67757: [yaml2obj/obj2yaml] - Add support for .stack_sizes sections.

[George Rimar via Phabricator via llvm-commits]

grimar marked an inline comment as done.
grimar added inline comments.


================
Comment at: include/llvm/ObjectYAML/ELFYAML.h:183
+  static bool nameMatches(StringRef Name) {
+    return Name.startswith(".stack_sizes");
+  }
----------------
MaskRay wrote:
> grimar wrote:
> > MaskRay wrote:
> > > I think we can just use `Name == ".stack_sizes"` for now. MC doesn't create `.stack_sizes.*`
> > > 
> > > Moreover, the error messages below just use plain `.stack_sizes`.
> > I am not sure here. I did it because llvm-readobj test case uses YAML with `.stack_sizes.*`:
> > https://github.com/llvm-mirror/llvm/blob/master/test/tools/llvm-readobj/stack-sizes.test#L35
> > 
> > I do not know was it intention or the person who wrote the test just did not know how to desribe sections with the same name in YAML.
> > It probably might be not that bad to support `.stack_sizes.*` too (and may be teach MC to produve them)?
> > Or we can fix `llvm-readobj` test first. Or go with `.stack_sizes.*` here and deside what to do in a follow-up patch for YAML+readobj.
> > What would you prefer?
> `Name.startswith(".stack_sizes");` is fine if we eventually emit `.stack_sizes.*` for clang -ffunction-sections -fstack-size-section. However, there are two problems:
> 
> * Larger code size. `.stack_sizes.foo`, `.text.foo` and `.rodata.foo` can take large amount of space in `.strtab`. This is why `-fno-unique-section-names` is sometimes useful.
> * Linkers don't combine `.stack_sizes.*` into `.stack_sizes`. ld.bfd and lld will have to be taught the special rule. In lld, it is in `getOutputSectionName`.
Seems the right way for now is to fix `llvm-readobj` then. I'll do a patch.


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