[PATCH] D100651: [AIX] Support of Big archive (read)

[Esme Yi via Phabricator via llvm-commits]

Esme added inline comments.


================
Comment at: llvm/lib/Object/Archive.cpp:1013
+    return child_end();
+  const char *Loc = Data.getBufferStart() + strlen(Magic) + sizeof(Archive::ArFixLenHdrType);
+  Child C(this, Loc, &Err);
----------------
It's not correct to calculate the offset of the first archive member by `Data.getBufferStart() + strlen(Magic) + sizeof(Archive::ArFixLenHdrType);`, please use the value of  `ArFixLenHdr->FirstArOffset`.
You can easily reproduce the bug if you test a archive file which contains a object file member like the comment I added before:
```
$ xlc 1.c -o 1.o
$ ar -v -q 1.a 1.o
$ llvm-ar tv 1.a
llvm-ar: error: unable to load '1.a': truncated or malformed archive (characters in size field in archive header are not all decimal numbers: '\000\000\000\000\000\000\000\000\000\0005892' for archive member header at offset 128)
``` 
The correct offset for this case should be 138 instead of 128.


Repository:
  rG LLVM Github Monorepo

CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D100651/new/

https://reviews.llvm.org/D100651