0031efe6be
Fixes #18763 Remove warnings when using a signed char as an array bound if the char is a known positive constant. This goes one step farther than gcc does. For example given the following code ```c++ char upper[300]; int main() { upper['a'] = 'A'; char b = 'a'; upper[b] = 'A'; const char c = 'a'; upper[c] = 'A'; constexpr char d = 'a'; upper[d] = 'A'; char e = -1; upper[e] = 'A'; const char f = -1; upper[f] = 'A'; constexpr char g = -1; upper[g] = 'A'; return 1; } ``` clang currently gives warnings for all cases, while gcc gives warnings for all cases except for 'a' (https://godbolt.org/z/5ahjETTv3) With the change there is no longer any warning for 'a', 'c', or 'd'.
104 lines
2.7 KiB
C++
104 lines
2.7 KiB
C++
// RUN: %clang_cc1 -Wchar-subscripts -fsyntax-only -verify %s
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void t1(void) {
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int array[1] = { 0 };
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char subscript = 0;
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int val = array[subscript]; // expected-warning{{array subscript is of type 'char'}}
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}
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void t2(void) {
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int array[1] = { 0 };
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char subscript = 0;
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int val = subscript[array]; // expected-warning{{array subscript is of type 'char'}}
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}
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void t3(void) {
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int *array = 0;
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char subscript = 0;
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int val = array[subscript]; // expected-warning{{array subscript is of type 'char'}}
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}
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void t4(void) {
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int *array = 0;
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char subscript = 0;
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int val = subscript[array]; // expected-warning{{array subscript is of type 'char'}}
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}
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char returnsChar(void);
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void t5(void) {
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int *array = 0;
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int val = array[returnsChar()]; // expected-warning{{array subscript is of type 'char'}}
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}
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void t6(void) {
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int array[1] = { 0 };
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signed char subscript = 0;
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int val = array[subscript]; // no warning for explicit signed char
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}
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void t7(void) {
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int array[1] = { 0 };
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unsigned char subscript = 0;
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int val = array[subscript]; // no warning for unsigned char
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}
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typedef char CharTy;
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void t8(void) {
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int array[1] = { 0 };
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CharTy subscript = 0;
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int val = array[subscript]; // expected-warning{{array subscript is of type 'char'}}
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}
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typedef signed char SignedCharTy;
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void t9(void) {
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int array[1] = { 0 };
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SignedCharTy subscript = 0;
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int val = array[subscript]; // no warning for explicit signed char
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}
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typedef unsigned char UnsignedCharTy;
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void t10(void) {
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int array[1] = { 0 };
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UnsignedCharTy subscript = 0;
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int val = array[subscript]; // no warning for unsigned char
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}
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void t11(void) {
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int array[256] = { 0 };
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int val = array['a']; // no warning for char with known positive value
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}
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void t12(void) {
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int array[256] = { 0 };
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char b = 'a';
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int val = array[b]; // expected-warning{{array subscript is of type 'char'}}
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}
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void t13(void) {
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int array[256] = { 0 };
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const char b = 'a';
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int val = array[b]; // no warning for char with known positive value
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}
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void t14(void) {
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int array[256] = { 0 };
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constexpr char b = 'a';
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int val = array[b]; // no warning for char with known positive value
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}
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void t15(void) {
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int array[256] = { 0 }; // expected-note {{array 'array' declared here}}
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const char b = -1;
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// expected-warning@+2 {{array subscript is of type 'char'}}
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// expected-warning@+1 {{array index -1 is before the beginning of the array}}
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int val = array[b];
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}
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void t16(void) {
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int array[256] = { 0 }; // expected-note {{array 'array' declared here}}
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constexpr char b = -1;
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// expected-warning@+2 {{array subscript is of type 'char'}}
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// expected-warning@+1 {{array index -1 is before the beginning of the array}}
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int val = array[b];
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}
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