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List:       cfe-commits
Subject:    [PATCH] D58724: [gnustep-objc] Make the GNUstep v2 ABI work for Windows DLLs.
From:       "Dustin L. Howett via Phabricator via cfe-commits" <cfe-commits () lists ! llvm ! org>
Date:       2019-02-28 19:07:15
Message-ID: c394cd35ce444cc2e9366eddb9967d48 () localhost ! localdomain
[Download RAW message or body]

DHowett-MSFT added inline comments.


================
Comment at: clang/lib/CodeGen/CGObjCGNU.cpp:188
 
+  StringRef SymbolPrefix() {
+    return CGM.getTriple().isOSBinFormatCOFF() ? "_" : "._";
----------------
theraven wrote:
> DHowett-MSFT wrote:
> > Should this be `SymbolPrefix()` or something more like `MangleSymbol(StringRef \
> > sym)`? I know that right now we only need to prepend `_` or `._`, but is it more \
> > future-proof to make it generic?
> I have refactored this, and then tried adding a $ instead of the . for mangling.  \
> On further testing, the latest link.exe from VS 2017 no longer complains about \
> symbols starting with a dot, so I'm inclined to revert that part of it entirely \
> (lld-link.exe was always happy).  I'd prefer to minimise differences between COFF \
> and ELF and this means that we have different section names, but aside from needing \
> the extra global initialisation on COFF, everything else is the same.  
The issue I had with symbols starting with `.` was in `.DEF` files specifically.

Linking a shared object containing:
```
@.exp_with_dot = dllexport global i32 0, align 4
```

without a def file, yields:

```
    ordinal hint RVA      name

          1    0 00012900 .exp_with_dot
```

However, linking the same library with a definition file:

###test.def
```
EXPORTS
 .exp_with_dot
```

yields

###output
```
test.def : fatal error LNK1242: '.exp_with_dot' is an invalid export symbol name
```

This still reproduces with 15.9.8, sadly. LINK version 14.16.27027.1.


Repository:
  rG LLVM Github Monorepo

CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D58724/new/

https://reviews.llvm.org/D58724



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