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Clang has traditionally allowed C programs to implicitly convert integers to pointers and pointers to integers, despite it not being valid to do so except under special circumstances (like converting the integer 0, which is the null pointer constant, to a pointer). In C89, this would result in undefined behavior per 3.3.4, and in C99 this rule was strengthened to be a constraint violation instead. Constraint violations are most often handled as an error. This patch changes the warning to default to an error in all C modes (it is already an error in C++). This gives us better security posture by calling out potential programmer mistakes in code but still allows users who need this behavior to use -Wno-error=int-conversion to retain the warning behavior, or -Wno-int-conversion to silence the diagnostic entirely. Differential Revision: https://reviews.llvm.org/D129881
5 lines
141 B
C
5 lines
141 B
C
// RUN: %clang_cc1 -emit-llvm -Wno-int-conversion < %s
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volatile unsigned char* const __attribute__((address_space(1))) serial_ctrl = 0x02;
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