877c84acd4
regcomp.c uses the "start + count < end" idiom to check that there are "count" bytes available in an array of char "start" and "end" both point to. This is fine, unless "start + count" goes beyond the last element of the array. In this case, pedantic interpretation of the C standard makes the comparison of such a pointer against "end" undefined, and optimizers from hell will happily remove as much code as possible because of this. An example of this occurs in regcomp.c's bothcases(), which defines bracket[3], sets "next" to "bracket" and "end" to "bracket + 2". Then it invokes p_bracket(), which starts with "if (p->next + 5 < p->end)"... Because bothcases() and p_bracket() are static functions in regcomp.c, there is a real risk of miscompilation if aggressive inlining happens. The following diff rewrites the "start + count < end" constructs into "end - start > count". Assuming "end" and "start" are always pointing in the array (such as "bracket[3]" above), "end - start" is well-defined and can be compared without trouble. As a bonus, MORE2() implies MORE() therefore SEETWO() can be simplified a bit. Bug report: https://github.com/llvm/llvm-project/issues/47993 Reviewed By: MaskRay, vitalybuka Differential Revision: https://reviews.llvm.org/D97129 |
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| runtimes | ||
| test | ||
| tools | ||
| unittests | ||
| utils | ||
| .clang-format | ||
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| .gitattributes | ||
| .gitignore | ||
| CMakeLists.txt | ||
| CODE_OWNERS.TXT | ||
| CREDITS.TXT | ||
| LICENSE.TXT | ||
| README.txt | ||
| RELEASE_TESTERS.TXT | ||
| configure | ||
| llvm.spec.in | ||
README.txt
The LLVM Compiler Infrastructure ================================ This directory and its subdirectories contain source code for LLVM, a toolkit for the construction of highly optimized compilers, optimizers, and runtime environments. LLVM is open source software. You may freely distribute it under the terms of the license agreement found in LICENSE.txt. Please see the documentation provided in docs/ for further assistance with LLVM, and in particular docs/GettingStarted.rst for getting started with LLVM and docs/README.txt for an overview of LLVM's documentation setup. If you are writing a package for LLVM, see docs/Packaging.rst for our suggestions.