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Commit 187230a7 by Joseph Myers Committed by Joseph Myers
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re PR c/12913 (Jumps into variable length array scope not rejected) 

	PR c/12913
	* c-tree.h (struct c_label_list): Update comment.
	(struct c_label_context): Rename to struct c_label_context_se.
	(label_context_stack): Rename to label_context_stack_se.
	(C_DECL_UNJUMPABLE_VM, C_DECL_UNDEFINABLE_VM, struct
	c_label_context_vm, label_context_stack_vm, c_begin_vm_scope,
	c_end_vm_scope): New.
	(C_DECL_DECLARED_BUILTIN, C_DECL_USED): Use FUNCTION_DECL_CHECK.
	* c-decl.c (pop_scope): Call c_end_vm_scope.
	(pushdecl): Call c_begin_vm_scope for variably modified
	declarations.
	(define_label): Check for jumping into scope of identifier with
	variably modified type.  Push label on stack for those defined at
	current context of identifiers with variably modified type.
	(start_function): Create stack level for context of identifiers
	with variably modified type.
	(finish_function): Pop stack level for context of identifiers with
	variably modified type.
	* c-typeck.c (label_context_stack): Rename to
	label_context_stack_se.
	(label_context_stack_vm, c_begin_vm_scope, c_end_vm_scope): New.
	(c_finish_goto_label): Check for jumping into scope of identifier
	with variably modified type.  Push label on stack for those jumped
	to from current context of identifiers with variably modified
	type.
	(struct c_switch): Add blocked_vm.
	(c_start_case): Initialize blocked_vm.
	(do_case): Check blocked_vm.
	(c_finish_case): Add comment.
	(c_begin_stmt_expr, c_finish_stmt_expr): Update for renamed
	variable label_context_stack.

objc:
	* objc-act.c (objc_start_function): Create stack level for context
	of identifiers with variably modified type.

testsuite:
	* gcc.dg/c99-vla-jump-1.c, gcc.dg/c99-vla-jump-2.c,
	gcc.dg/c99-vla-jump-3.c, gcc.dg/c99-vla-jump-4.c,
	gcc.dg/c99-vla-jump-5.c: New tests.

From-SVN: r98464
parent 2a925431
Showing with 290 additions and 39 deletions
gcc/ChangeLog
2005-04-20 Joseph S. Myers <joseph@codesourcery.com>
PR c/12913
* c-tree.h (struct c_label_list): Update comment.
(struct c_label_context): Rename to struct c_label_context_se.
(label_context_stack): Rename to label_context_stack_se.
(C_DECL_UNJUMPABLE_VM, C_DECL_UNDEFINABLE_VM, struct
c_label_context_vm, label_context_stack_vm, c_begin_vm_scope,
c_end_vm_scope): New.
(C_DECL_DECLARED_BUILTIN, C_DECL_USED): Use FUNCTION_DECL_CHECK.
* c-decl.c (pop_scope): Call c_end_vm_scope.
(pushdecl): Call c_begin_vm_scope for variably modified
declarations.
(define_label): Check for jumping into scope of identifier with
variably modified type. Push label on stack for those defined at
current context of identifiers with variably modified type.
(start_function): Create stack level for context of identifiers
with variably modified type.
(finish_function): Pop stack level for context of identifiers with
variably modified type.
* c-typeck.c (label_context_stack): Rename to
label_context_stack_se.
(label_context_stack_vm, c_begin_vm_scope, c_end_vm_scope): New.
(c_finish_goto_label): Check for jumping into scope of identifier
with variably modified type. Push label on stack for those jumped
to from current context of identifiers with variably modified
type.
(struct c_switch): Add blocked_vm.
(c_start_case): Initialize blocked_vm.
(do_case): Check blocked_vm.
(c_finish_case): Add comment.
(c_begin_stmt_expr, c_finish_stmt_expr): Update for renamed
variable label_context_stack.
2005-04-20 Kazu Hirata <kazu@cs.umass.edu>
* tree-ssa-phiopt.c (tree_ssa_phi_opt): Update calls to
......
gcc/c-decl.c
......@@ -673,6 +673,8 @@ pop_scope (void)
bool functionbody = scope->function_body;
bool keep = functionbody || scope->keep || scope->bindings;
c_end_vm_scope (scope->depth);
/* If appropriate, create a BLOCK to record the decls for the life
of this function. */
block = 0;
......@@ -1983,6 +1985,12 @@ pushdecl (tree x)
|| DECL_INITIAL (x) || !DECL_EXTERNAL (x)))
DECL_CONTEXT (x) = current_function_decl;
/* If this is of variably modified type, prevent jumping into its
scope. */
if ((TREE_CODE (x) == VAR_DECL || TREE_CODE (x) == TYPE_DECL)
&& variably_modified_type_p (TREE_TYPE (x), NULL_TREE))
c_begin_vm_scope (scope->depth);
/* Anonymous decls are just inserted in the scope. */
if (!name)
{
......@@ -2439,7 +2447,7 @@ define_label (location_t location, tree name)
if there is a containing function with a declared label with
the same name. */
tree label = I_LABEL_DECL (name);
struct c_label_list *nlist;
struct c_label_list *nlist_se, *nlist_vm;
if (label
&& ((DECL_CONTEXT (label) == current_function_decl
......@@ -2458,6 +2466,9 @@ define_label (location_t location, tree name)
definition. */
if (C_DECL_UNDEFINABLE_STMT_EXPR (label))
error ("%Jjump into statement expression", label);
if (C_DECL_UNDEFINABLE_VM (label))
error ("%Jjump into scope of identifier with variably modified type",
label);
DECL_SOURCE_LOCATION (label) = location;
}
else
......@@ -2474,10 +2485,15 @@ define_label (location_t location, tree name)
warning ("%Htraditional C lacks a separate namespace for labels, "
"identifier %qE conflicts", &location, name);
nlist = XOBNEW (&parser_obstack, struct c_label_list);
nlist->next = label_context_stack->labels_def;
nlist->label = label;
label_context_stack->labels_def = nlist;
nlist_se = XOBNEW (&parser_obstack, struct c_label_list);
nlist_se->next = label_context_stack_se->labels_def;
nlist_se->label = label;
label_context_stack_se->labels_def = nlist_se;
nlist_vm = XOBNEW (&parser_obstack, struct c_label_list);
nlist_vm->next = label_context_stack_vm->labels_def;
nlist_vm->label = label;
label_context_stack_vm->labels_def = nlist_vm;
/* Mark label as having been defined. */
DECL_INITIAL (label) = error_mark_node;
......@@ -5637,7 +5653,8 @@ start_function (struct c_declspecs *declspecs, struct c_declarator *declarator,
{
tree decl1, old_decl;
tree restype, resdecl;
struct c_label_context *nstack;
struct c_label_context_se *nstack_se;
struct c_label_context_vm *nstack_vm;
current_function_returns_value = 0; /* Assume, until we see it does. */
current_function_returns_null = 0;
......@@ -5646,11 +5663,18 @@ start_function (struct c_declspecs *declspecs, struct c_declarator *declarator,
current_extern_inline = 0;
c_switch_stack = NULL;
nstack = XOBNEW (&parser_obstack, struct c_label_context);
nstack->labels_def = NULL;
nstack->labels_used = NULL;
nstack->next = label_context_stack;
label_context_stack = nstack;
nstack_se = XOBNEW (&parser_obstack, struct c_label_context_se);
nstack_se->labels_def = NULL;
nstack_se->labels_used = NULL;
nstack_se->next = label_context_stack_se;
label_context_stack_se = nstack_se;
nstack_vm = XOBNEW (&parser_obstack, struct c_label_context_vm);
nstack_vm->labels_def = NULL;
nstack_vm->labels_used = NULL;
nstack_vm->scope = 0;
nstack_vm->next = label_context_stack_vm;
label_context_stack_vm = nstack_vm;
/* Indicate no valid break/continue context by setting these variables
to some non-null, non-label value. We'll notice and emit the proper
......@@ -6233,7 +6257,8 @@ finish_function (void)
{
tree fndecl = current_function_decl;
label_context_stack = label_context_stack->next;
label_context_stack_se = label_context_stack_se->next;
label_context_stack_vm = label_context_stack_vm->next;
if (TREE_CODE (fndecl) == FUNCTION_DECL
&& targetm.calls.promote_prototypes (TREE_TYPE (fndecl)))
......
gcc/c-tree.h
......@@ -86,7 +86,8 @@ struct lang_type GTY(())
/* For FUNCTION_DECLs, evaluates true if the decl is built-in but has
been declared. */
#define C_DECL_DECLARED_BUILTIN(EXP) DECL_LANG_FLAG_3 (EXP)
#define C_DECL_DECLARED_BUILTIN(EXP) \
DECL_LANG_FLAG_3 (FUNCTION_DECL_CHECK (EXP))
/* Record whether a decl was declared register. This is strictly a
front-end flag, whereas DECL_REGISTER is used for code generation;
......@@ -97,7 +98,7 @@ struct lang_type GTY(())
unevaluated operand of sizeof / typeof / alignof. This is only
used for functions declared static but not defined, though outside
sizeof and typeof it is set for other function decls as well. */
#define C_DECL_USED(EXP) DECL_LANG_FLAG_5 (EXP)
#define C_DECL_USED(EXP) DECL_LANG_FLAG_5 (FUNCTION_DECL_CHECK (EXP))
/* Record whether a label was defined in a statement expression which
has finished and so can no longer be jumped to. */
......@@ -110,6 +111,18 @@ struct lang_type GTY(())
#define C_DECL_UNDEFINABLE_STMT_EXPR(EXP) \
DECL_LANG_FLAG_7 (LABEL_DECL_CHECK (EXP))
/* Record whether a label was defined in the scope of an identifier
with variably modified type which has finished and so can no longer
be jumped to. */
#define C_DECL_UNJUMPABLE_VM(EXP) \
DECL_LANG_FLAG_3 (LABEL_DECL_CHECK (EXP))
/* Record whether a label was the subject of a goto from outside the
current level of scopes of identifiers with variably modified type
and so cannot be defined right now. */
#define C_DECL_UNDEFINABLE_VM(EXP) \
DECL_LANG_FLAG_5 (LABEL_DECL_CHECK (EXP))
/* Nonzero for a decl which either doesn't exist or isn't a prototype.
N.B. Could be simplified if all built-in decls had complete prototypes
(but this is presently difficult because some of them need FILE*). */
......@@ -354,8 +367,8 @@ struct language_function GTY(())
int extern_inline;
};
/* Save lists of labels used or defined in particular statement
expression contexts. Allocated on the parser obstack. */
/* Save lists of labels used or defined in particular contexts.
Allocated on the parser obstack. */
struct c_label_list
{
......@@ -365,14 +378,32 @@ struct c_label_list
struct c_label_list *next;
};
struct c_label_context
/* Statement expression context. */
struct c_label_context_se
{
/* The labels defined at this level of nesting. */
struct c_label_list *labels_def;
/* The labels used at this level of nesting. */
struct c_label_list *labels_used;
/* The next outermost context. */
struct c_label_context_se *next;
};
/* Context of variably modified declarations. */
struct c_label_context_vm
{
/* The labels defined at this level of nesting. */
struct c_label_list *labels_def;
/* The labels used at this level of nesting. */
struct c_label_list *labels_used;
/* The scope of this context. Multiple contexts may be at the same
numbered scope, since each variably modified declaration starts a
new context. */
unsigned scope;
/* The next outermost context. */
struct c_label_context *next;
struct c_label_context_vm *next;
};
......@@ -477,7 +508,8 @@ extern int in_sizeof;
extern int in_typeof;
extern struct c_switch *c_switch_stack;
extern struct c_label_context *label_context_stack;
extern struct c_label_context_se *label_context_stack_se;
extern struct c_label_context_vm *label_context_stack_vm;
extern tree require_complete_type (tree);
extern int same_translation_unit_p (tree, tree);
......@@ -532,6 +564,8 @@ extern tree c_finish_return (tree);
extern tree c_finish_bc_stmt (tree *, bool);
extern tree c_finish_goto_label (tree);
extern tree c_finish_goto_ptr (tree);
extern void c_begin_vm_scope (unsigned int);
extern void c_end_vm_scope (unsigned int);
/* Set to 0 at beginning of a function definition, set to 1 if
a return statement that specifies a return value is seen. */
......
gcc/c-typeck.c
......@@ -64,7 +64,8 @@ int in_sizeof;
/* The level of nesting inside "typeof". */
int in_typeof;
struct c_label_context *label_context_stack;
struct c_label_context_se *label_context_stack_se;
struct c_label_context_vm *label_context_stack_vm;
/* Nonzero if we've already printed a "missing braces around initializer"
message within this initializer. */
......@@ -6495,15 +6496,33 @@ c_finish_goto_label (tree label)
return NULL_TREE;
}
if (C_DECL_UNJUMPABLE_VM (decl))
{
error ("jump into scope of identifier with variably modified type");
return NULL_TREE;
}
if (!C_DECL_UNDEFINABLE_STMT_EXPR (decl))
{
/* No jump from outside this statement expression context, so
record that there is a jump from within this context. */
struct c_label_list *nlist;
nlist = XOBNEW (&parser_obstack, struct c_label_list);
nlist->next = label_context_stack->labels_used;
nlist->next = label_context_stack_se->labels_used;
nlist->label = decl;
label_context_stack_se->labels_used = nlist;
}
if (!C_DECL_UNDEFINABLE_VM (decl))
{
/* No jump from outside this context context of identifiers with
variably modified type, so record that there is a jump from
within this context. */
struct c_label_list *nlist;
nlist = XOBNEW (&parser_obstack, struct c_label_list);
nlist->next = label_context_stack_vm->labels_used;
nlist->label = decl;
label_context_stack->labels_used = nlist;
label_context_stack_vm->labels_used = nlist;
}
TREE_USED (decl) = 1;
......@@ -6637,6 +6656,11 @@ struct c_switch {
appear. */
unsigned int blocked_stmt_expr;
/* Scope of outermost declarations of identifiers with variably
modified type within this switch statement; if nonzero, case and
default labels may not appear. */
unsigned int blocked_vm;
/* The next node on the stack. */
struct c_switch *next;
};
......@@ -6692,6 +6716,7 @@ c_start_case (tree exp)
cs->orig_type = orig_type;
cs->cases = splay_tree_new (case_compare, NULL, NULL);
cs->blocked_stmt_expr = 0;
cs->blocked_vm = 0;
cs->next = c_switch_stack;
c_switch_stack = cs;
......@@ -6705,7 +6730,8 @@ do_case (tree low_value, tree high_value)
{
tree label = NULL_TREE;
if (c_switch_stack && !c_switch_stack->blocked_stmt_expr)
if (c_switch_stack && !c_switch_stack->blocked_stmt_expr
&& !c_switch_stack->blocked_vm)
{
label = c_add_case_label (c_switch_stack->cases,
SWITCH_COND (c_switch_stack->switch_expr),
......@@ -6723,6 +6749,15 @@ do_case (tree low_value, tree high_value)
error ("%<default%> label in statement expression not containing "
"enclosing switch statement");
}
else if (c_switch_stack && c_switch_stack->blocked_vm)
{
if (low_value)
error ("case label in scope of identifier with variably modified "
"type not containing enclosing switch statement");
else
error ("%<default%> label in scope of identifier with variably "
"modified type not containing enclosing switch statement");
}
else if (low_value)
error ("case label not within a switch statement");
else
......@@ -6741,6 +6776,9 @@ c_finish_case (tree body)
SWITCH_BODY (cs->switch_expr) = body;
/* We must not be within a statement expression nested in the switch
at this point; we might, however, be within the scope of an
identifier with variably modified type nested in the switch. */
gcc_assert (!cs->blocked_stmt_expr);
/* Emit warnings as needed. */
......@@ -7015,7 +7053,7 @@ tree
c_begin_stmt_expr (void)
{
tree ret;
struct c_label_context *nstack;
struct c_label_context_se *nstack;
struct c_label_list *glist;
/* We must force a BLOCK for this level so that, if it is not expanded
......@@ -7028,17 +7066,17 @@ c_begin_stmt_expr (void)
c_switch_stack->blocked_stmt_expr++;
gcc_assert (c_switch_stack->blocked_stmt_expr != 0);
}
for (glist = label_context_stack->labels_used;
for (glist = label_context_stack_se->labels_used;
glist != NULL;
glist = glist->next)
{
C_DECL_UNDEFINABLE_STMT_EXPR (glist->label) = 1;
}
nstack = XOBNEW (&parser_obstack, struct c_label_context);
nstack = XOBNEW (&parser_obstack, struct c_label_context_se);
nstack->labels_def = NULL;
nstack->labels_used = NULL;
nstack->next = label_context_stack;
label_context_stack = nstack;
nstack->next = label_context_stack_se;
label_context_stack_se = nstack;
/* Mark the current statement list as belonging to a statement list. */
STATEMENT_LIST_STMT_EXPR (ret) = 1;
......@@ -7061,7 +7099,7 @@ c_finish_stmt_expr (tree body)
}
/* It is no longer possible to jump to labels defined within this
statement expression. */
for (dlist = label_context_stack->labels_def;
for (dlist = label_context_stack_se->labels_def;
dlist != NULL;
dlist = dlist->next)
{
......@@ -7069,7 +7107,7 @@ c_finish_stmt_expr (tree body)
}
/* It is again possible to define labels with a goto just outside
this statement expression. */
for (glist = label_context_stack->next->labels_used;
for (glist = label_context_stack_se->next->labels_used;
glist != NULL;
glist = glist->next)
{
......@@ -7077,10 +7115,11 @@ c_finish_stmt_expr (tree body)
glist_prev = glist;
}
if (glist_prev != NULL)
glist_prev->next = label_context_stack->labels_used;
glist_prev->next = label_context_stack_se->labels_used;
else
label_context_stack->next->labels_used = label_context_stack->labels_used;
label_context_stack = label_context_stack->next;
label_context_stack_se->next->labels_used
= label_context_stack_se->labels_used;
label_context_stack_se = label_context_stack_se->next;
/* Locate the last statement in BODY. See c_end_compound_stmt
about always returning a BIND_EXPR. */
......@@ -7151,6 +7190,75 @@ c_finish_stmt_expr (tree body)
return build4 (TARGET_EXPR, type, tmp, body, NULL_TREE, NULL_TREE);
}
/* Begin the scope of an identifier of variably modified type, scope
number SCOPE. Jumping from outside this scope to inside it is not
permitted. */
void
c_begin_vm_scope (unsigned int scope)
{
struct c_label_context_vm *nstack;
struct c_label_list *glist;
gcc_assert (scope > 0);
if (c_switch_stack && !c_switch_stack->blocked_vm)
c_switch_stack->blocked_vm = scope;
for (glist = label_context_stack_vm->labels_used;
glist != NULL;
glist = glist->next)
{
C_DECL_UNDEFINABLE_VM (glist->label) = 1;
}
nstack = XOBNEW (&parser_obstack, struct c_label_context_vm);
nstack->labels_def = NULL;
nstack->labels_used = NULL;
nstack->scope = scope;
nstack->next = label_context_stack_vm;
label_context_stack_vm = nstack;
}
/* End a scope which may contain identifiers of variably modified
type, scope number SCOPE. */
void
c_end_vm_scope (unsigned int scope)
{
if (label_context_stack_vm == NULL)
return;
if (c_switch_stack && c_switch_stack->blocked_vm == scope)
c_switch_stack->blocked_vm = 0;
/* We may have a number of nested scopes of identifiers with
variably modified type, all at this depth. Pop each in turn. */
while (label_context_stack_vm->scope == scope)
{
struct c_label_list *dlist, *glist, *glist_prev = NULL;
/* It is no longer possible to jump to labels defined within this
scope. */
for (dlist = label_context_stack_vm->labels_def;
dlist != NULL;
dlist = dlist->next)
{
C_DECL_UNJUMPABLE_VM (dlist->label) = 1;
}
/* It is again possible to define labels with a goto just outside
this scope. */
for (glist = label_context_stack_vm->next->labels_used;
glist != NULL;
glist = glist->next)
{
C_DECL_UNDEFINABLE_VM (glist->label) = 0;
glist_prev = glist;
}
if (glist_prev != NULL)
glist_prev->next = label_context_stack_vm->labels_used;
else
label_context_stack_vm->next->labels_used
= label_context_stack_vm->labels_used;
label_context_stack_vm = label_context_stack_vm->next;
}
}
/* Begin and end compound statements. This is as simple as pushing
and popping new statement lists from the tree. */
......
gcc/objc/ChangeLog
2005-04-20 Joseph S. Myers <joseph@codesourcery.com>
PR c/12913
* objc-act.c (objc_start_function): Create stack level for context
of identifiers with variably modified type.
2005-03-30 Joseph S. Myers <joseph@codesourcery.com>
PR c/772
......
gcc/objc/objc-act.c
......@@ -7666,12 +7666,19 @@ objc_start_function (tree name, tree type, tree attrs,
cplus_decl_attributes (&fndecl, attrs, 0);
start_preparsed_function (fndecl, attrs, /*flags=*/SF_DEFAULT);
#else
struct c_label_context *nstack;
nstack = XOBNEW (&parser_obstack, struct c_label_context);
nstack->labels_def = NULL;
nstack->labels_used = NULL;
nstack->next = label_context_stack;
label_context_stack = nstack;
struct c_label_context_se *nstack_se;
struct c_label_context_vm *nstack_vm;
nstack_se = XOBNEW (&parser_obstack, struct c_label_context_se);
nstack_se->labels_def = NULL;
nstack_se->labels_used = NULL;
nstack_se->next = label_context_stack_se;
label_context_stack_se = nstack_se;
nstack_vm = XOBNEW (&parser_obstack, struct c_label_context_vm);
nstack_vm->labels_def = NULL;
nstack_vm->labels_used = NULL;
nstack_vm->scope = 0;
nstack_vm->next = label_context_stack_vm;
label_context_stack_vm = nstack_vm;
decl_attributes (&fndecl, attrs, 0);
announce_function (fndecl);
DECL_INITIAL (fndecl) = error_mark_node;
......
gcc/testsuite/ChangeLog
2005-04-20 Joseph S. Myers <joseph@codesourcery.com>
PR c/12913
* gcc.dg/c99-vla-jump-1.c, gcc.dg/c99-vla-jump-2.c,
gcc.dg/c99-vla-jump-3.c, gcc.dg/c99-vla-jump-4.c,
gcc.dg/c99-vla-jump-5.c: New tests.
2005-04-19 Richard Henderson <rth@redhat.com>
* lib/target-supports.exp (check_effective_target_vect_int_mult):
......
gcc/testsuite/gcc.dg/c99-vla-jump-2.c 0 → 100644
This source diff could not be displayed because it is too large. You can view the blob instead.
gcc/testsuite/gcc.dg/c99-vla-jump-4.c 0 → 100644
This source diff could not be displayed because it is too large. You can view the blob instead.
gcc/testsuite/gcc.dg/c99-vla-jump-5.c 0 → 100644
/* Test for labels and VM declarations: bug 12913.
switch statements must not jump into the scope of VM declarations.
c99-vla-jump-1.c tests with just that label and goto, VLAs.
c99-vla-jump-2.c tests with many other labels and gotos, VLAs.
c99-vla-jump-3.c tests with just that label and goto, VM.
c99-vla-jump-4.c tests with many other labels and gotos, VM.
c99-vla-jump-5.c tests with switch statements. */
/* Origin: Joseph Myers <joseph@codesourcery.com> */
/* { dg-do compile } */
/* { dg-options "-std=iso9899:1999 -pedantic-errors" } */
void
f (int a, int b)
{
switch (a) {
int v[b];
case 2: /* { dg-error "error: case label in scope of identifier with variably modified type not containing enclosing switch statement" } */
default: /* { dg-error "error: 'default' label in scope of identifier with variably modified type not containing enclosing switch statement" } */
switch (a)
{
case 4:
{ int z[b]; }
default:
;
int w[b];
}
}
}
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