[PATCH] D97663: [llvm-objcopy] Fix crash for binary input files with non-ascii names

[Fangrui Song via Phabricator via llvm-commits]

MaskRay added a comment.

C11 says

> The header <ctype.h> declares several functions useful for classifying and mapping characters.198) In all cases the argument is an int, the value of which shall be representable as an unsigned char or shall equal the value of the macro EOF. If the argument has any other value, the behavior is undefined.

The crash problem you described may be similar to https://drewdevault.com/2020/09/25/A-story-of-two-libcs.html
With certain values (negative ones?) glibc may crash.



================
Comment at: llvm/tools/llvm-objcopy/ELF/Object.cpp:1294
   std::replace_if(std::begin(SanitizedFilename), std::end(SanitizedFilename),
-                  [](char C) { return !isalnum(C); }, '_');
+                  [](char C) { return !isAlnum(C); }, '_');
   Twine Prefix = Twine("_binary_") + SanitizedFilename;
----------------
may need an `unsigned char` cast.


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