When tokens in macro definitions need cstr_buf inside get_tok_str, the second might overwrite the first (happens when tokens are multi-character non-identifiers, see testcase) in macro_is_equal, failing to diagnose a difference. Use a real local buffer.
Unified · Split
| @@ -1280,17 +1280,18 @@ static int macro_is_equal(const int *a, const int *b) · 1279 unmodified lines | ||
| 1280 | 1280 | { |
| 1281 | 1281 | CValue cv; |
| 1282 | 1282 | int t; |
| 1283 | + static CString localbuf; | |
| 1283 | 1284 | |
| 1284 | 1285 | if (!a || !b) |
| 1285 | 1286 | return 1; |
| 1286 | 1287 | |
| 1287 | 1288 | while (*a && *b) { |
| 1288 | − /* first time preallocate static cstr_buf, next time only reset position to start */ | |
| 1289 | − cstr_reset(&cstr_buf); | |
| 1289 | + /* first time preallocate static localbuf, next time only reset position to start */ | |
| 1290 | + cstr_reset(&localbuf); | |
| 1290 | 1291 | TOK_GET(&t, &a, &cv); |
| 1291 | − cstr_cat(&cstr_buf, get_tok_str(t, &cv), 0); | |
| 1292 | + cstr_cat(&localbuf, get_tok_str(t, &cv), 0); | |
| 1292 | 1293 | TOK_GET(&t, &b, &cv); |
| 1293 | − if (strcmp(cstr_buf.data, get_tok_str(t, &cv))) | |
| 1294 | + if (strcmp(localbuf.data, get_tok_str(t, &cv))) | |
| 1294 | 1295 | return 0; |
| 1295 | 1296 | } |
| 1296 | 1297 | return !(*a || *b); |
| @@ -0,0 +1,3 @@ | ||
| 1 | +/* The following should warn */ | |
| 2 | +#define A ... | |
| 3 | +#define A <<= | |
| @@ -0,0 +1,2 @@ | ||
| 1 | + | |
| 2 | +16.c:3: warning: A redefined | |