Date: Wed, 13 Nov 2013 04:31:27 +0000 (UTC) From: "Pedro F. Giffuni" <pfg@FreeBSD.org> To: src-committers@freebsd.org, svn-src-all@freebsd.org, svn-src-head@freebsd.org Subject: svn commit: r258081 - in head/contrib/gcc: . cp doc Message-ID: <201311130431.rAD4VRMa058157@svn.freebsd.org>
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Author: pfg Date: Wed Nov 13 04:31:27 2013 New Revision: 258081 URL: http://svnweb.freebsd.org/changeset/base/258081 Log: gcc: Backport fixes for -W parentheses in C++ This fixes GCC 19564: http://gcc.gnu.org/ml/gcc-patches/2006-12/msg00868.html http://gcc.gnu.org/ml/gcc-patches/2006-12/msg01772.html http://gcc.gnu.org/ml/gcc-patches/2007-01/msg00545.html The patch and its fixes are used by Google in their enhanced gcc-4.2.1 port and predates the license switch in GCC so they are still under GPLv2. MFC after: 3 weeks Modified: head/contrib/gcc/ChangeLog.gcc43 head/contrib/gcc/c-common.c head/contrib/gcc/c-common.h head/contrib/gcc/c-typeck.c head/contrib/gcc/cp/cp-tree.h head/contrib/gcc/cp/parser.c head/contrib/gcc/cp/pt.c head/contrib/gcc/cp/semantics.c head/contrib/gcc/cp/typeck.c head/contrib/gcc/doc/invoke.texi Modified: head/contrib/gcc/ChangeLog.gcc43 ============================================================================== --- head/contrib/gcc/ChangeLog.gcc43 Wed Nov 13 03:50:31 2013 (r258080) +++ head/contrib/gcc/ChangeLog.gcc43 Wed Nov 13 04:31:27 2013 (r258081) @@ -232,6 +232,17 @@ * config.gcc: Support core2 processor. +2006-12-13 Ian Lance Taylor <iant@google.com> (r119855) + + PR c++/19564 + PR c++/19756 + * c-typeck.c (parser_build_binary_op): Move parentheses warnings + to warn_about_parentheses in c-common.c. + * c-common.c (warn_about_parentheses): New function. + * c-common.h (warn_about_parentheses): Declare. + * doc/invoke.texi (Warning Options): Update -Wparentheses + description. + 2006-12-02 H.J. Lu <hongjiu.lu@intel.com> (r119454 - partial) PR target/30040 Modified: head/contrib/gcc/c-common.c ============================================================================== --- head/contrib/gcc/c-common.c Wed Nov 13 03:50:31 2013 (r258080) +++ head/contrib/gcc/c-common.c Wed Nov 13 04:31:27 2013 (r258081) @@ -2585,9 +2585,13 @@ c_common_truthvalue_conversion (tree exp 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 (tre 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" Modified: head/contrib/gcc/c-common.h ============================================================================== --- head/contrib/gcc/c-common.h Wed Nov 13 03:50:31 2013 (r258080) +++ head/contrib/gcc/c-common.h Wed Nov 13 04:31:27 2013 (r258081) @@ -850,6 +850,9 @@ extern int complete_array_type (tree *, extern tree builtin_type_for_size (int, bool); extern void warn_array_subscript_with_type_char (tree); +extern void warn_about_parentheses (enum tree_code, enum tree_code, + enum tree_code); + /* In c-gimplify.c */ extern void c_genericize (tree); Modified: head/contrib/gcc/c-typeck.c ============================================================================== --- head/contrib/gcc/c-typeck.c Wed Nov 13 03:50:31 2013 (r258080) +++ head/contrib/gcc/c-typeck.c Wed Nov 13 04:31:27 2013 (r258081) @@ -2631,73 +2631,7 @@ parser_build_binary_op (enum tree_code c /* Check for cases such as x+y<<z which users are likely to misinterpret. */ if (warn_parentheses) - { - if (code == LSHIFT_EXPR || code == RSHIFT_EXPR) - { - if (code1 == PLUS_EXPR || code1 == MINUS_EXPR - || code2 == PLUS_EXPR || code2 == MINUS_EXPR) - warning (OPT_Wparentheses, - "suggest parentheses around + or - inside shift"); - } - - if (code == TRUTH_ORIF_EXPR) - { - if (code1 == TRUTH_ANDIF_EXPR - || code2 == TRUTH_ANDIF_EXPR) - warning (OPT_Wparentheses, - "suggest parentheses around && within ||"); - } - - if (code == BIT_IOR_EXPR) - { - if (code1 == BIT_AND_EXPR || code1 == BIT_XOR_EXPR - || code1 == PLUS_EXPR || code1 == MINUS_EXPR - || code2 == BIT_AND_EXPR || code2 == BIT_XOR_EXPR - || code2 == PLUS_EXPR || code2 == MINUS_EXPR) - warning (OPT_Wparentheses, - "suggest parentheses around arithmetic in operand of |"); - /* Check cases like x|y==z */ - if (TREE_CODE_CLASS (code1) == tcc_comparison - || TREE_CODE_CLASS (code2) == tcc_comparison) - warning (OPT_Wparentheses, - "suggest parentheses around comparison in operand of |"); - } - - if (code == BIT_XOR_EXPR) - { - if (code1 == BIT_AND_EXPR - || code1 == PLUS_EXPR || code1 == MINUS_EXPR - || code2 == BIT_AND_EXPR - || code2 == PLUS_EXPR || code2 == MINUS_EXPR) - warning (OPT_Wparentheses, - "suggest parentheses around arithmetic in operand of ^"); - /* Check cases like x^y==z */ - if (TREE_CODE_CLASS (code1) == tcc_comparison - || TREE_CODE_CLASS (code2) == tcc_comparison) - warning (OPT_Wparentheses, - "suggest parentheses around comparison in operand of ^"); - } - - if (code == BIT_AND_EXPR) - { - if (code1 == PLUS_EXPR || code1 == MINUS_EXPR - || code2 == PLUS_EXPR || code2 == MINUS_EXPR) - warning (OPT_Wparentheses, - "suggest parentheses around + or - in operand of &"); - /* Check cases like x&y==z */ - if (TREE_CODE_CLASS (code1) == tcc_comparison - || TREE_CODE_CLASS (code2) == 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 (code1) == tcc_comparison - || TREE_CODE_CLASS (code2) == tcc_comparison)) - warning (OPT_Wparentheses, "comparisons like X<=Y<=Z do not " - "have their mathematical meaning"); - - } + warn_about_parentheses (code, code1, code2); /* Warn about comparisons against string literals, with the exception of testing for equality or inequality of a string literal with NULL. */ Modified: head/contrib/gcc/cp/cp-tree.h ============================================================================== --- head/contrib/gcc/cp/cp-tree.h Wed Nov 13 03:50:31 2013 (r258080) +++ head/contrib/gcc/cp/cp-tree.h Wed Nov 13 04:31:27 2013 (r258081) @@ -4460,8 +4460,9 @@ extern tree build_x_indirect_ref (tree, extern tree build_indirect_ref (tree, const char *); extern tree build_array_ref (tree, tree); extern tree get_member_function_from_ptrfunc (tree *, tree); -extern tree build_x_binary_op (enum tree_code, tree, tree, - bool *); +extern tree build_x_binary_op (enum tree_code, tree, + enum tree_code, tree, + enum tree_code, bool *); extern tree build_x_unary_op (enum tree_code, tree); extern tree unary_complex_lvalue (enum tree_code, tree); extern tree build_x_conditional_expr (tree, tree, tree); Modified: head/contrib/gcc/cp/parser.c ============================================================================== --- head/contrib/gcc/cp/parser.c Wed Nov 13 03:50:31 2013 (r258080) +++ head/contrib/gcc/cp/parser.c Wed Nov 13 04:31:27 2013 (r258081) @@ -1177,8 +1177,15 @@ typedef enum cp_parser_status_kind typedef struct cp_parser_expression_stack_entry { + /* Left hand side of the binary operation we are currently + parsing. */ tree lhs; + /* Original tree code for left hand side, if it was a binary + expression itself (used for -Wparentheses). */ + enum tree_code lhs_type; + /* Tree code for the binary operation we are parsing. */ enum tree_code tree_type; + /* Precedence of the binary operation we are parsing. */ int prec; } cp_parser_expression_stack_entry; @@ -1536,7 +1543,7 @@ static tree cp_parser_builtin_offsetof /* Statements [gram.stmt.stmt] */ static void cp_parser_statement - (cp_parser *, tree, bool); + (cp_parser *, tree, bool, bool *); static void cp_parser_label_for_labeled_statement (cp_parser *); static tree cp_parser_expression_statement @@ -1546,7 +1553,7 @@ static tree cp_parser_compound_statement static void cp_parser_statement_seq_opt (cp_parser *, tree); static tree cp_parser_selection_statement - (cp_parser *); + (cp_parser *, bool *); static tree cp_parser_condition (cp_parser *); static tree cp_parser_iteration_statement @@ -1559,7 +1566,7 @@ static void cp_parser_declaration_statem (cp_parser *); static tree cp_parser_implicitly_scoped_statement - (cp_parser *); + (cp_parser *, bool *); static void cp_parser_already_scoped_statement (cp_parser *); @@ -5730,12 +5737,13 @@ cp_parser_binary_expression (cp_parser* cp_parser_expression_stack_entry *sp = &stack[0]; tree lhs, rhs; cp_token *token; - enum tree_code tree_type; + enum tree_code tree_type, lhs_type, rhs_type; enum cp_parser_prec prec = PREC_NOT_OPERATOR, new_prec, lookahead_prec; bool overloaded_p; /* Parse the first expression. */ lhs = cp_parser_cast_expression (parser, /*address_p=*/false, cast_p); + lhs_type = ERROR_MARK; for (;;) { @@ -5768,6 +5776,7 @@ cp_parser_binary_expression (cp_parser* /* Extract another operand. It may be the RHS of this expression or the LHS of a new, higher priority expression. */ rhs = cp_parser_simple_cast_expression (parser); + rhs_type = ERROR_MARK; /* Get another operator token. Look up its precedence to avoid building a useless (immediately popped) stack entry for common @@ -5783,8 +5792,10 @@ cp_parser_binary_expression (cp_parser* sp->prec = prec; sp->tree_type = tree_type; sp->lhs = lhs; + sp->lhs_type = lhs_type; sp++; lhs = rhs; + lhs_type = rhs_type; prec = new_prec; new_prec = lookahead_prec; goto get_rhs; @@ -5801,11 +5812,15 @@ cp_parser_binary_expression (cp_parser* prec = sp->prec; tree_type = sp->tree_type; rhs = lhs; + rhs_type = lhs_type; lhs = sp->lhs; + lhs_type = sp->lhs_type; } overloaded_p = false; - lhs = build_x_binary_op (tree_type, lhs, rhs, &overloaded_p); + lhs = build_x_binary_op (tree_type, lhs, lhs_type, rhs, rhs_type, + &overloaded_p); + lhs_type = tree_type; /* If the binary operator required the use of an overloaded operator, then this expression cannot be an integral constant-expression. @@ -6222,17 +6237,23 @@ cp_parser_builtin_offsetof (cp_parser *p try-block IN_COMPOUND is true when the statement is nested inside a - cp_parser_compound_statement; this matters for certain pragmas. */ + cp_parser_compound_statement; this matters for certain pragmas. + + If IF_P is not NULL, *IF_P is set to indicate whether the statement + is a (possibly labeled) if statement which is not enclosed in braces + and has an else clause. This is used to implement -Wparentheses. */ static void cp_parser_statement (cp_parser* parser, tree in_statement_expr, - bool in_compound) + bool in_compound, bool *if_p) { tree statement; cp_token *token; location_t statement_location; restart: + if (if_p != NULL) + *if_p = false; /* There is no statement yet. */ statement = NULL_TREE; /* Peek at the next token. */ @@ -6257,7 +6278,7 @@ cp_parser_statement (cp_parser* parser, case RID_IF: case RID_SWITCH: - statement = cp_parser_selection_statement (parser); + statement = cp_parser_selection_statement (parser, if_p); break; case RID_WHILE: @@ -6522,7 +6543,7 @@ cp_parser_statement_seq_opt (cp_parser* break; /* Parse the statement. */ - cp_parser_statement (parser, in_statement_expr, true); + cp_parser_statement (parser, in_statement_expr, true, NULL); } } @@ -6533,14 +6554,22 @@ cp_parser_statement_seq_opt (cp_parser* if ( condition ) statement else statement switch ( condition ) statement - Returns the new IF_STMT or SWITCH_STMT. */ + Returns the new IF_STMT or SWITCH_STMT. + + If IF_P is not NULL, *IF_P is set to indicate whether the statement + is a (possibly labeled) if statement which is not enclosed in + braces and has an else clause. This is used to implement + -Wparentheses. */ static tree -cp_parser_selection_statement (cp_parser* parser) +cp_parser_selection_statement (cp_parser* parser, bool *if_p) { cp_token *token; enum rid keyword; + if (if_p != NULL) + *if_p = false; + /* Peek at the next token. */ token = cp_parser_require (parser, CPP_KEYWORD, "selection-statement"); @@ -6576,11 +6605,13 @@ cp_parser_selection_statement (cp_parser if (keyword == RID_IF) { + bool nested_if; + /* Add the condition. */ finish_if_stmt_cond (condition, statement); /* Parse the then-clause. */ - cp_parser_implicitly_scoped_statement (parser); + cp_parser_implicitly_scoped_statement (parser, &nested_if); finish_then_clause (statement); /* If the next token is `else', parse the else-clause. */ @@ -6591,8 +6622,28 @@ cp_parser_selection_statement (cp_parser cp_lexer_consume_token (parser->lexer); begin_else_clause (statement); /* Parse the else-clause. */ - cp_parser_implicitly_scoped_statement (parser); + cp_parser_implicitly_scoped_statement (parser, NULL); finish_else_clause (statement); + + /* If we are currently parsing a then-clause, then + IF_P will not be NULL. We set it to true to + indicate that this if statement has an else clause. + This may trigger the Wparentheses warning below + when we get back up to the parent if statement. */ + if (if_p != NULL) + *if_p = true; + } + else + { + /* This if statement does not have an else clause. If + NESTED_IF is true, then the then-clause is an if + statement which does have an else clause. We warn + about the potential ambiguity. */ + if (nested_if) + warning (OPT_Wparentheses, + ("%Hsuggest explicit braces " + "to avoid ambiguous %<else%>"), + EXPR_LOCUS (statement)); } /* Now we're all done with the if-statement. */ @@ -6611,7 +6662,7 @@ cp_parser_selection_statement (cp_parser in_statement = parser->in_statement; parser->in_switch_statement_p = true; parser->in_statement |= IN_SWITCH_STMT; - cp_parser_implicitly_scoped_statement (parser); + cp_parser_implicitly_scoped_statement (parser, NULL); parser->in_switch_statement_p = in_switch_statement_p; parser->in_statement = in_statement; @@ -6789,7 +6840,7 @@ cp_parser_iteration_statement (cp_parser statement = begin_do_stmt (); /* Parse the body of the do-statement. */ parser->in_statement = IN_ITERATION_STMT; - cp_parser_implicitly_scoped_statement (parser); + cp_parser_implicitly_scoped_statement (parser, NULL); parser->in_statement = in_statement; finish_do_body (statement); /* Look for the `while' keyword. */ @@ -7031,13 +7082,21 @@ cp_parser_declaration_statement (cp_pars but ensures that is in its own scope, even if it is not a compound-statement. + If IF_P is not NULL, *IF_P is set to indicate whether the statement + is a (possibly labeled) if statement which is not enclosed in + braces and has an else clause. This is used to implement + -Wparentheses. + Returns the new statement. */ static tree -cp_parser_implicitly_scoped_statement (cp_parser* parser) +cp_parser_implicitly_scoped_statement (cp_parser* parser, bool *if_p) { tree statement; + if (if_p != NULL) + *if_p = false; + /* Mark if () ; with a special NOP_EXPR. */ if (cp_lexer_next_token_is (parser->lexer, CPP_SEMICOLON)) { @@ -7053,7 +7112,7 @@ cp_parser_implicitly_scoped_statement (c /* Create a compound-statement. */ statement = begin_compound_stmt (0); /* Parse the dependent-statement. */ - cp_parser_statement (parser, NULL_TREE, false); + cp_parser_statement (parser, NULL_TREE, false, if_p); /* Finish the dummy compound-statement. */ finish_compound_stmt (statement); } @@ -7072,7 +7131,7 @@ cp_parser_already_scoped_statement (cp_p { /* If the token is a `{', then we must take special action. */ if (cp_lexer_next_token_is_not (parser->lexer, CPP_OPEN_BRACE)) - cp_parser_statement (parser, NULL_TREE, false); + cp_parser_statement (parser, NULL_TREE, false, NULL); else { /* Avoid calling cp_parser_compound_statement, so that we @@ -18645,7 +18704,7 @@ cp_parser_omp_structured_block (cp_parse tree stmt = begin_omp_structured_block (); unsigned int save = cp_parser_begin_omp_structured_block (parser); - cp_parser_statement (parser, NULL_TREE, false); + cp_parser_statement (parser, NULL_TREE, false, NULL); cp_parser_end_omp_structured_block (parser, save); return finish_omp_structured_block (stmt); @@ -18890,7 +18949,7 @@ cp_parser_omp_for_loop (cp_parser *parse /* Note that the grammar doesn't call for a structured block here, though the loop as a whole is a structured block. */ body = push_stmt_list (); - cp_parser_statement (parser, NULL_TREE, false); + cp_parser_statement (parser, NULL_TREE, false, NULL); body = pop_stmt_list (body); return finish_omp_for (loc, decl, init, cond, incr, body, pre_body); @@ -18983,7 +19042,7 @@ cp_parser_omp_sections_scope (cp_parser while (1) { - cp_parser_statement (parser, NULL_TREE, false); + cp_parser_statement (parser, NULL_TREE, false, NULL); tok = cp_lexer_peek_token (parser->lexer); if (tok->pragma_kind == PRAGMA_OMP_SECTION) Modified: head/contrib/gcc/cp/pt.c ============================================================================== --- head/contrib/gcc/cp/pt.c Wed Nov 13 03:50:31 2013 (r258080) +++ head/contrib/gcc/cp/pt.c Wed Nov 13 04:31:27 2013 (r258081) @@ -9078,7 +9078,13 @@ tsubst_copy_and_build (tree t, return build_x_binary_op (TREE_CODE (t), RECUR (TREE_OPERAND (t, 0)), + (TREE_NO_WARNING (TREE_OPERAND (t, 0)) + ? ERROR_MARK + : TREE_CODE (TREE_OPERAND (t, 0))), RECUR (TREE_OPERAND (t, 1)), + (TREE_NO_WARNING (TREE_OPERAND (t, 1)) + ? ERROR_MARK + : TREE_CODE (TREE_OPERAND (t, 1))), /*overloaded_p=*/NULL); case SCOPE_REF: @@ -9087,7 +9093,14 @@ tsubst_copy_and_build (tree t, case ARRAY_REF: op1 = tsubst_non_call_postfix_expression (TREE_OPERAND (t, 0), args, complain, in_decl); - return build_x_binary_op (ARRAY_REF, op1, RECUR (TREE_OPERAND (t, 1)), + return build_x_binary_op (ARRAY_REF, op1, + (TREE_NO_WARNING (TREE_OPERAND (t, 0)) + ? ERROR_MARK + : TREE_CODE (TREE_OPERAND (t, 0))), + RECUR (TREE_OPERAND (t, 1)), + (TREE_NO_WARNING (TREE_OPERAND (t, 1)) + ? ERROR_MARK + : TREE_CODE (TREE_OPERAND (t, 1))), /*overloaded_p=*/NULL); case SIZEOF_EXPR: Modified: head/contrib/gcc/cp/semantics.c ============================================================================== --- head/contrib/gcc/cp/semantics.c Wed Nov 13 03:50:31 2013 (r258080) +++ head/contrib/gcc/cp/semantics.c Wed Nov 13 04:31:27 2013 (r258081) @@ -587,6 +587,16 @@ maybe_convert_cond (tree cond) /* Do the conversion. */ cond = convert_from_reference (cond); + + if (TREE_CODE (cond) == MODIFY_EXPR + && !TREE_NO_WARNING (cond) + && warn_parentheses) + { + warning (OPT_Wparentheses, + "suggest parentheses around assignment used as truth value"); + TREE_NO_WARNING (cond) = 1; + } + return condition_conversion (cond); } Modified: head/contrib/gcc/cp/typeck.c ============================================================================== --- head/contrib/gcc/cp/typeck.c Wed Nov 13 03:50:31 2013 (r258080) +++ head/contrib/gcc/cp/typeck.c Wed Nov 13 04:31:27 2013 (r258081) @@ -1690,17 +1690,20 @@ rationalize_conditional_expr (enum tree_ are equal, so we know what conditional expression this used to be. */ if (TREE_CODE (t) == MIN_EXPR || TREE_CODE (t) == MAX_EXPR) { + tree op0 = TREE_OPERAND (t, 0); + tree op1 = TREE_OPERAND (t, 1); + /* The following code is incorrect if either operand side-effects. */ - gcc_assert (!TREE_SIDE_EFFECTS (TREE_OPERAND (t, 0)) - && !TREE_SIDE_EFFECTS (TREE_OPERAND (t, 1))); + gcc_assert (!TREE_SIDE_EFFECTS (op0) + && !TREE_SIDE_EFFECTS (op1)); return build_conditional_expr (build_x_binary_op ((TREE_CODE (t) == MIN_EXPR ? LE_EXPR : GE_EXPR), - TREE_OPERAND (t, 0), - TREE_OPERAND (t, 1), + op0, TREE_CODE (op0), + op1, TREE_CODE (op1), /*overloaded_p=*/NULL), - build_unary_op (code, TREE_OPERAND (t, 0), 0), - build_unary_op (code, TREE_OPERAND (t, 1), 0)); + build_unary_op (code, op0, 0), + build_unary_op (code, op1, 0)); } return @@ -2908,8 +2911,8 @@ convert_arguments (tree typelist, tree v conversions on the operands. CODE is the kind of expression to build. */ tree -build_x_binary_op (enum tree_code code, tree arg1, tree arg2, - bool *overloaded_p) +build_x_binary_op (enum tree_code code, tree arg1, enum tree_code arg1_code, + tree arg2, enum tree_code arg2_code, bool *overloaded_p) { tree orig_arg1; tree orig_arg2; @@ -2933,6 +2936,17 @@ build_x_binary_op (enum tree_code code, expr = build_new_op (code, LOOKUP_NORMAL, arg1, arg2, NULL_TREE, overloaded_p); + /* Check for cases such as x+y<<z which users are likely to + misinterpret. But don't warn about obj << x + y, since that is a + common idiom for I/O. */ + if (warn_parentheses + && !processing_template_decl + && !error_operand_p (arg1) + && !error_operand_p (arg2) + && (code != LSHIFT_EXPR + || !IS_AGGR_TYPE (TREE_TYPE (arg1)))) + warn_about_parentheses (code, arg1_code, arg2_code); + if (processing_template_decl && expr != error_mark_node) return build_min_non_dep (code, expr, orig_arg1, orig_arg2); @@ -6280,6 +6294,19 @@ convert_for_assignment (tree type, tree errtype); } + /* If -Wparentheses, warn about a = b = c when a has type bool and b + does not. */ + if (warn_parentheses + && type == boolean_type_node + && TREE_CODE (rhs) == MODIFY_EXPR + && !TREE_NO_WARNING (rhs) + && TREE_TYPE (rhs) != boolean_type_node) + { + warning (OPT_Wparentheses, + "suggest parentheses around assignment used as truth value"); + TREE_NO_WARNING (rhs) = 1; + } + return perform_implicit_conversion (strip_top_quals (type), rhs); } Modified: head/contrib/gcc/doc/invoke.texi ============================================================================== --- head/contrib/gcc/doc/invoke.texi Wed Nov 13 03:50:31 2013 (r258080) +++ head/contrib/gcc/doc/invoke.texi Wed Nov 13 04:31:27 2013 (r258081) @@ -2212,9 +2212,7 @@ Warn if a user-supplied include director Warn if parentheses are omitted in certain contexts, such as when there is an assignment in a context where a truth value is expected, or when operators are nested whose precedence people -often get confused about. Only the warning for an assignment used as -a truth value is supported when compiling C++; the other warnings are -only supported when compiling C@. +often get confused about. Also warn if a comparison like @samp{x<=y<=z} appears; this is equivalent to @samp{(x<=y ? 1 : 0) <= z}, which is a different @@ -2236,14 +2234,15 @@ such a case: @end group @end smallexample -In C, every @code{else} branch belongs to the innermost possible @code{if} -statement, which in this example is @code{if (b)}. This is often not -what the programmer expected, as illustrated in the above example by -indentation the programmer chose. When there is the potential for this -confusion, GCC will issue a warning when this flag is specified. -To eliminate the warning, add explicit braces around the innermost -@code{if} statement so there is no way the @code{else} could belong to -the enclosing @code{if}. The resulting code would look like this: +In C/C++, every @code{else} branch belongs to the innermost possible +@code{if} statement, which in this example is @code{if (b)}. This is +often not what the programmer expected, as illustrated in the above +example by indentation the programmer chose. When there is the +potential for this confusion, GCC will issue a warning when this flag +is specified. To eliminate the warning, add explicit braces around +the innermost @code{if} statement so there is no way the @code{else} +could belong to the enclosing @code{if}. The resulting code would +look like this: @smallexample @group
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