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author | Luc Van Oostenryck <luc.vanoostenryck@gmail.com> | 2020-08-18 22:00:41 +0200 |
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committer | Luc Van Oostenryck <luc.vanoostenryck@gmail.com> | 2020-08-18 22:00:41 +0200 |
commit | 101649206777f00be5c23f60f87f01066ad64ece (patch) | |
tree | c1f17a02ef5823f9af19f4f7a9735930716a4dbe | |
parent | ad7af4347d271874378a7d826a91fd05e41d4051 (diff) | |
parent | 8b3cbf54ad42c68f5ea2fa5bc2cef5ce9e608571 (diff) | |
download | sparse-101649206777f00be5c23f60f87f01066ad64ece.tar.gz |
Merge branch 'union-cast' into master
* teach sparse about union casts
-rw-r--r-- | Documentation/release-notes/v0.6.3.rst | 5 | ||||
-rw-r--r-- | evaluate.c | 88 | ||||
-rw-r--r-- | options.c | 2 | ||||
-rw-r--r-- | options.h | 1 | ||||
-rw-r--r-- | sparse.1 | 6 | ||||
-rw-r--r-- | validation/eval/union-cast-no.c | 23 | ||||
-rw-r--r-- | validation/eval/union-cast.c | 24 |
7 files changed, 129 insertions, 20 deletions
diff --git a/Documentation/release-notes/v0.6.3.rst b/Documentation/release-notes/v0.6.3.rst new file mode 100644 index 00000000..1aae742e --- /dev/null +++ b/Documentation/release-notes/v0.6.3.rst @@ -0,0 +1,5 @@ +v0.6.3 (2020-xx-xy) +=================== + +* Changes in warnings: + "warning: cast to union type" [disable with -Wno-union-cast] @@ -2946,11 +2946,52 @@ static int cast_flags(struct expression *expr, struct expression *old) return flags; } +/// +// check if a type matches one of the members of a union type +// @utype: the union type +// @type: to type to check +// @return: to identifier of the matching type in the union. +static struct symbol *find_member_type(struct symbol *utype, struct symbol *type) +{ + struct symbol *t, *member; + + if (utype->type != SYM_UNION) + return NULL; + + FOR_EACH_PTR(utype->symbol_list, member) { + classify_type(member, &t); + if (type == t) + return member; + } END_FOR_EACH_PTR(member); + return NULL; +} + +static struct symbol *evaluate_compound_literal(struct expression *expr, struct expression *source) +{ + struct expression *addr = alloc_expression(expr->pos, EXPR_SYMBOL); + struct symbol *sym = expr->cast_type; + + sym->initializer = source; + evaluate_symbol(sym); + + addr->ctype = &lazy_ptr_ctype; /* Lazy eval */ + addr->symbol = sym; + if (sym->ctype.modifiers & MOD_TOPLEVEL) + addr->flags |= CEF_ADDR; + + expr->type = EXPR_PREOP; + expr->op = '*'; + expr->deref = addr; + expr->ctype = sym; + return sym; +} + static struct symbol *evaluate_cast(struct expression *expr) { struct expression *source = expr->cast_expression; struct symbol *ctype; struct symbol *ttype, *stype; + struct symbol *member; int tclass, sclass; struct ident *tas = NULL, *sas = NULL; @@ -2968,25 +3009,8 @@ static struct symbol *evaluate_cast(struct expression *expr) * dereferenced as part of a post-fix expression. * We need to produce an expression that can be dereferenced. */ - if (source->type == EXPR_INITIALIZER) { - struct symbol *sym = expr->cast_type; - struct expression *addr = alloc_expression(expr->pos, EXPR_SYMBOL); - - sym->initializer = source; - evaluate_symbol(sym); - - addr->ctype = &lazy_ptr_ctype; /* Lazy eval */ - addr->symbol = sym; - if (sym->ctype.modifiers & MOD_TOPLEVEL) - addr->flags |= CEF_ADDR; - - expr->type = EXPR_PREOP; - expr->op = '*'; - expr->unop = addr; - expr->ctype = sym; - - return sym; - } + if (source->type == EXPR_INITIALIZER) + return evaluate_compound_literal(expr, source); ctype = examine_symbol_type(expr->cast_type); expr->ctype = ctype; @@ -3017,8 +3041,32 @@ static struct symbol *evaluate_cast(struct expression *expr) if (expr->type == EXPR_FORCE_CAST) goto out; - if (tclass & (TYPE_COMPOUND | TYPE_FN)) + if (tclass & (TYPE_COMPOUND | TYPE_FN)) { + /* + * Special case: cast to union type (GCC extension) + * The effect is similar to a compound literal except + * that the result is a rvalue. + */ + if ((member = find_member_type(ttype, stype))) { + struct expression *item, *init; + + if (Wunion_cast) + warning(expr->pos, "cast to union type"); + + item = alloc_expression(source->pos, EXPR_IDENTIFIER); + item->expr_ident = member->ident; + item->ident_expression = source; + + init = alloc_expression(source->pos, EXPR_INITIALIZER); + add_expression(&init->expr_list, item); + + // FIXME: this should be a rvalue + evaluate_compound_literal(expr, init); + return ctype; + } + warning(expr->pos, "cast to non-scalar"); + } if (sclass & TYPE_COMPOUND) warning(expr->pos, "cast from non-scalar"); @@ -130,6 +130,7 @@ int Wtransparent_union = 0; int Wtypesign = 0; int Wundef = 0; int Wuninitialized = 1; +int Wunion_cast = 0; int Wuniversal_initializer = 0; int Wunknown_attribute = 0; int Wvla = 1; @@ -868,6 +869,7 @@ static const struct flag warnings[] = { { "typesign", &Wtypesign }, { "undef", &Wundef }, { "uninitialized", &Wuninitialized }, + { "union-cast", &Wunion_cast }, { "universal-initializer", &Wuniversal_initializer }, { "unknown-attribute", &Wunknown_attribute }, { "vla", &Wvla }, @@ -129,6 +129,7 @@ extern int Wtransparent_union; extern int Wtypesign; extern int Wundef; extern int Wuninitialized; +extern int Wunion_cast; extern int Wuniversal_initializer; extern int Wunknown_attribute; extern int Wvla; @@ -458,6 +458,12 @@ The concerned warnings are, for example, those triggered by Sparse does not issue these warnings by default, processing '{\ 0\ }' the same as '{\ }'. . +.TP +.B -Wunion-cast +Warn on casts to union types. + +Sparse does not issues these warnings by default. +. .SH MISC OPTIONS .TP .B \-\-arch=\fIARCH\fR diff --git a/validation/eval/union-cast-no.c b/validation/eval/union-cast-no.c new file mode 100644 index 00000000..6ba38db8 --- /dev/null +++ b/validation/eval/union-cast-no.c @@ -0,0 +1,23 @@ +union u { + int i; + char x[8]; +}; + +static union u foo(int i) +{ + return (union u)i; +} + +static union u bar(long l) +{ + return (union u)l; +} + +/* + * check-name: union-cast-no + * check-command: sparse -Wno-union-cast $file + * + * check-error-start +eval/union-cast-no.c:13:17: warning: cast to non-scalar + * check-error-end + */ diff --git a/validation/eval/union-cast.c b/validation/eval/union-cast.c new file mode 100644 index 00000000..5bee9e0d --- /dev/null +++ b/validation/eval/union-cast.c @@ -0,0 +1,24 @@ +union u { + int i; + char x[8]; +}; + +static union u foo(int a) +{ + return (union u)a; +} + +static union u bar(long a) +{ + return (union u)a; +} + +/* + * check-name: union-cast + * check-command: sparse -Wunion-cast $file + * + * check-error-start +eval/union-cast.c:8:17: warning: cast to union type +eval/union-cast.c:13:17: warning: cast to non-scalar + * check-error-end + */ |