| commit | a05e736d288a7f2009ee9d057e78713d9adeeb5f | [log] [tgz] |
|---|---|---|
| author | Vitaly Buka <vitalybuka@google.com> | Fri Nov 17 15:13:11 2023 -0800 |
| committer | GitHub <noreply@github.com> | Fri Nov 17 15:13:11 2023 -0800 |
| tree | c14591bbee646878d7fac2c4eacdfbc4d3395784 | |
| parent | 506c47df00bbd9e527ecc5ac6e192b5fe5daa2c5 [diff] |
[msan][x86] Fix shadow if vararg overflow beyond kParamTLSSize Caller puts argument shadow one by one into __msan_va_arg_tls, until it reaches kParamTLSSize. After that it still increment OverflowOffset but does not store the shadow. Callee needs OverflowOffset to prepare a shadow for the entire overflow area. It's done by creating "varargs shadow copy" for complete list of args, copying available shadow from __msan_va_arg_tls, and clearing the rest. However callee does not know if the tail of __msan_va_arg_tls was not able to fit an argument, and callee will copy tail shadow into "varargs shadow copy", and later used as a shadow for an omitted argument. So that unused tail of the __msan_va_arg_tls must be cleared if left unused. This allows us to enable compiler-rt/test/msan/vararg_shadow.cpp for x86. Reviewers: kstoimenov, thurstond Reviewed By: thurstond Pull Request: https://github.com/llvm/llvm-project/pull/72707
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