From e03e58c1844d04678f95b278f3eff2a5fbaeff75 Mon Sep 17 00:00:00 2001 From: Martin Liska Date: Tue, 23 Feb 2021 11:14:03 +0100 Subject: [PATCH] Fix UBSAN in __ubsan::Value::getSIntValue /home/marxin/Programming/gcc2/libsanitizer/ubsan/ubsan_value.cpp:77:25: runtime error: left shift of 0x0000000000000000fffffffffffffffb by 96 places cannot be represented in type '__int128' #0 0x7ffff754edfe in __ubsan::Value::getSIntValue() const /home/marxin/Programming/gcc2/libsanitizer/ubsan/ubsan_value.cpp:77 #1 0x7ffff7548719 in __ubsan::Value::isNegative() const /home/marxin/Programming/gcc2/libsanitizer/ubsan/ubsan_value.h:190 #2 0x7ffff7542a34 in handleShiftOutOfBoundsImpl /home/marxin/Programming/gcc2/libsanitizer/ubsan/ubsan_handlers.cpp:338 #3 0x7ffff75431b7 in __ubsan_handle_shift_out_of_bounds /home/marxin/Programming/gcc2/libsanitizer/ubsan/ubsan_handlers.cpp:370 #4 0x40067f in main (/home/marxin/Programming/testcases/a.out+0x40067f) #5 0x7ffff72c8b24 in __libc_start_main (/lib64/libc.so.6+0x27b24) #6 0x4005bd in _start (/home/marxin/Programming/testcases/a.out+0x4005bd) Differential Revision: https://reviews.llvm.org/D97263 Cherry-pick from 16ede0956cb1f4b692dfa619ccfa6ab1de28e19b. --- libsanitizer/ubsan/ubsan_value.cpp | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/libsanitizer/ubsan/ubsan_value.cpp b/libsanitizer/ubsan/ubsan_value.cpp index 79c3ba991d39..40042bf3a903 100644 --- a/libsanitizer/ubsan/ubsan_value.cpp +++ b/libsanitizer/ubsan/ubsan_value.cpp @@ -74,7 +74,7 @@ SIntMax Value::getSIntValue() const { // to SIntMax. const unsigned ExtraBits = sizeof(SIntMax) * 8 - getType().getIntegerBitWidth(); - return SIntMax(Val) << ExtraBits >> ExtraBits; + return SIntMax(UIntMax(Val) << ExtraBits) >> ExtraBits; } if (getType().getIntegerBitWidth() == 64) return *reinterpret_cast(Val);