diff options
Diffstat (limited to 'contrib/gcc/c-common.c')
| -rw-r--r-- | contrib/gcc/c-common.c | 92 |
1 files changed, 89 insertions, 3 deletions
diff --git a/contrib/gcc/c-common.c b/contrib/gcc/c-common.c index b5ea608..9a04130 100644 --- a/contrib/gcc/c-common.c +++ b/contrib/gcc/c-common.c @@ -2585,9 +2585,13 @@ c_common_truthvalue_conversion (tree expr) break; case MODIFY_EXPR: - if (!TREE_NO_WARNING (expr)) - warning (OPT_Wparentheses, - "suggest parentheses around assignment used as truth value"); + if (!TREE_NO_WARNING (expr) + && warn_parentheses) + { + warning (OPT_Wparentheses, + "suggest parentheses around assignment used as truth value"); + TREE_NO_WARNING (expr) = 1; + } break; default: @@ -6471,5 +6475,87 @@ warn_array_subscript_with_type_char (tree index) warning (OPT_Wchar_subscripts, "array subscript has type %<char%>"); } +/* Implement -Wparentheses for the unexpected C precedence rules, to + cover cases like x + y << z which readers are likely to + misinterpret. We have seen an expression in which CODE is a binary + operator used to combine expressions headed by CODE_LEFT and + CODE_RIGHT. CODE_LEFT and CODE_RIGHT may be ERROR_MARK, which + means that that side of the expression was not formed using a + binary operator, or it was enclosed in parentheses. */ + +void +warn_about_parentheses (enum tree_code code, enum tree_code code_left, + enum tree_code code_right) +{ + if (!warn_parentheses) + return; + + if (code == LSHIFT_EXPR || code == RSHIFT_EXPR) + { + if (code_left == PLUS_EXPR || code_left == MINUS_EXPR + || code_right == PLUS_EXPR || code_right == MINUS_EXPR) + warning (OPT_Wparentheses, + "suggest parentheses around + or - inside shift"); + } + + if (code == TRUTH_ORIF_EXPR) + { + if (code_left == TRUTH_ANDIF_EXPR + || code_right == TRUTH_ANDIF_EXPR) + warning (OPT_Wparentheses, + "suggest parentheses around && within ||"); + } + + if (code == BIT_IOR_EXPR) + { + if (code_left == BIT_AND_EXPR || code_left == BIT_XOR_EXPR + || code_left == PLUS_EXPR || code_left == MINUS_EXPR + || code_right == BIT_AND_EXPR || code_right == BIT_XOR_EXPR + || code_right == PLUS_EXPR || code_right == MINUS_EXPR) + warning (OPT_Wparentheses, + "suggest parentheses around arithmetic in operand of |"); + /* Check cases like x|y==z */ + if (TREE_CODE_CLASS (code_left) == tcc_comparison + || TREE_CODE_CLASS (code_right) == tcc_comparison) + warning (OPT_Wparentheses, + "suggest parentheses around comparison in operand of |"); + } + + if (code == BIT_XOR_EXPR) + { + if (code_left == BIT_AND_EXPR + || code_left == PLUS_EXPR || code_left == MINUS_EXPR + || code_right == BIT_AND_EXPR + || code_right == PLUS_EXPR || code_right == MINUS_EXPR) + warning (OPT_Wparentheses, + "suggest parentheses around arithmetic in operand of ^"); + /* Check cases like x^y==z */ + if (TREE_CODE_CLASS (code_left) == tcc_comparison + || TREE_CODE_CLASS (code_right) == tcc_comparison) + warning (OPT_Wparentheses, + "suggest parentheses around comparison in operand of ^"); + } + + if (code == BIT_AND_EXPR) + { + if (code_left == PLUS_EXPR || code_left == MINUS_EXPR + || code_right == PLUS_EXPR || code_right == MINUS_EXPR) + warning (OPT_Wparentheses, + "suggest parentheses around + or - in operand of &"); + /* Check cases like x&y==z */ + if (TREE_CODE_CLASS (code_left) == tcc_comparison + || TREE_CODE_CLASS (code_right) == tcc_comparison) + warning (OPT_Wparentheses, + "suggest parentheses around comparison in operand of &"); + } + + /* Similarly, check for cases like 1<=i<=10 that are probably errors. */ + if (TREE_CODE_CLASS (code) == tcc_comparison + && (TREE_CODE_CLASS (code_left) == tcc_comparison + || TREE_CODE_CLASS (code_right) == tcc_comparison)) + warning (OPT_Wparentheses, "comparisons like X<=Y<=Z do not " + "have their mathematical meaning"); +} + #include "gt-c-common.h" |
