Further _cpp_parse_expr () cleanup
Neil Booth
neil@daikokuya.demon.co.uk
Sun Apr 28 14:41:00 GMT 2002
My previous patch would cause an (invalid) expression beginning
with ':' to underflow the stack when looking for the truth
value of the expression preceding the '?'.
This patch fixes that with a testcase. It also moves token lexing to
_cpp_parse_expr(), allowing better diagnostics and removal of the
function op_as_text(). That leaves lex() doing half of its old job,
namely converting various tokens into values, and so is renamed
eval_token().
Neil.
* cppexp.c (lex): Move some code to _cpp_parse_expr, but
keep most cases as function eval_token.
(eval_token): New function.
(_cpp_parse_expr): Read token here for improved diagnostics.
Don't use op_as_text. Detect bad ':' here.
(reduce): Don't detect bad ':' here.
(op_as_text): Remove.
* cpphash.h (_cpp_test_assertion): Change prototype.
* cpplib.c (_cpp_test_assertion): Change prototype.
Index: cppexp.c
===================================================================
RCS file: /cvs/gcc/gcc/gcc/cppexp.c,v
retrieving revision 1.110
diff -u -p -r1.110 cppexp.c
--- cppexp.c 28 Apr 2002 19:42:29 -0000 1.110
+++ cppexp.c 28 Apr 2002 21:13:23 -0000
@@ -36,8 +36,7 @@ static HOST_WIDEST_INT right_shift PARAM
unsigned HOST_WIDEST_INT));
static struct op parse_number PARAMS ((cpp_reader *, const cpp_token *));
static struct op parse_defined PARAMS ((cpp_reader *));
-static struct op lex PARAMS ((cpp_reader *));
-static const unsigned char *op_as_text PARAMS ((cpp_reader *, enum cpp_ttype));
+static struct op eval_token PARAMS ((cpp_reader *, const cpp_token *));
static struct op *reduce PARAMS ((cpp_reader *, struct op *, enum cpp_ttype));
struct op
@@ -275,45 +274,30 @@ parse_defined (pfile)
return op;
}
-/* Read a token. The returned type is CPP_NUMBER for a valid number
- (an interpreted preprocessing number or character constant, or the
- result of the "defined" or "#" operators), CPP_ERROR on error,
- CPP_EOF, or the type of an operator token. */
+/* Convert a token into a CPP_NUMBER (an interpreted preprocessing
+ number or character constant, or the result of the "defined" or "#"
+ operators), or CPP_ERROR on error. */
static struct op
-lex (pfile)
+eval_token (pfile, token)
cpp_reader *pfile;
+ const cpp_token *token;
{
+ unsigned int temp;
struct op op;
- const cpp_token *token = cpp_get_token (pfile);
+
+ op.op = CPP_NUMBER;
+ op.unsignedp = 0;
switch (token->type)
{
case CPP_NUMBER:
return parse_number (pfile, token);
- case CPP_CHAR:
case CPP_WCHAR:
- {
- unsigned int chars_seen;
-
- if (token->type == CPP_CHAR)
- op.unsignedp = 0;
- else
- op.unsignedp = WCHAR_UNSIGNED;
- op.op = CPP_NUMBER;
- op.value = cpp_interpret_charconst (pfile, token, 1, &chars_seen);
- return op;
- }
-
- case CPP_STRING:
- case CPP_WSTRING:
- SYNTAX_ERROR ("string constants are not valid in #if");
-
- case CPP_OTHER:
- if (ISGRAPH (token->val.c))
- SYNTAX_ERROR2 ("invalid character '%c' in #if", token->val.c);
- else
- SYNTAX_ERROR2 ("invalid character '\\%03o' in #if", token->val.c);
+ op.unsignedp = WCHAR_UNSIGNED;
+ case CPP_CHAR: /* Always unsigned. */
+ op.value = cpp_interpret_charconst (pfile, token, 1, &temp);
+ break;
case CPP_NAME:
if (token->val.node == pfile->spec_nodes.n_defined)
@@ -322,8 +306,6 @@ lex (pfile)
&& (token->val.node == pfile->spec_nodes.n_true
|| token->val.node == pfile->spec_nodes.n_false))
{
- op.op = CPP_NUMBER;
- op.unsignedp = 0;
op.value = (token->val.node == pfile->spec_nodes.n_true);
/* Warn about use of true or false in #if when pedantic
@@ -333,46 +315,22 @@ lex (pfile)
cpp_error (pfile, DL_PEDWARN,
"ISO C++ does not permit \"%s\" in #if",
NODE_NAME (token->val.node));
- return op;
}
else
{
- op.op = CPP_NUMBER;
- op.unsignedp = 0;
op.value = 0;
-
if (CPP_OPTION (pfile, warn_undef) && !pfile->state.skip_eval)
cpp_error (pfile, DL_WARNING, "\"%s\" is not defined",
NODE_NAME (token->val.node));
- return op;
}
+ break;
- case CPP_HASH:
- {
- int temp;
-
- op.op = CPP_NUMBER;
- if (_cpp_test_assertion (pfile, &temp))
- op.op = CPP_ERROR;
- op.unsignedp = 0;
- op.value = temp;
- return op;
- }
-
- default:
- if (((int) token->type > (int) CPP_EQ
- && (int) token->type < (int) CPP_PLUS_EQ))
- {
- op.op = token->type;
- return op;
- }
-
- SYNTAX_ERROR2 ("\"%s\" is not valid in #if expressions",
- cpp_token_as_text (pfile, token));
+ default: /* CPP_HASH */
+ if (_cpp_test_assertion (pfile, &temp))
+ op.op = CPP_ERROR;
+ op.value = temp;
}
- syntax_error:
- op.op = CPP_ERROR;
return op;
}
@@ -459,7 +417,7 @@ extra semantics need to be handled with
N entries of enum cpp_ttype. */
static const struct operator
{
- uchar prio; /* Priorities are even. */
+ uchar prio;
uchar flags;
} optab[] =
{
@@ -539,6 +497,7 @@ _cpp_parse_expr (pfile)
cpp_reader *pfile;
{
struct op *top = pfile->op_stack;
+ const cpp_token *token = NULL, *prev_token;
unsigned int lex_count;
bool saw_leading_not, want_value = true;
@@ -556,19 +515,26 @@ _cpp_parse_expr (pfile)
{
struct op op;
- /* Read a token */
- op = lex (pfile);
+ prev_token = token;
+ token = cpp_get_token (pfile);
lex_count++;
+ op.op = token->type;
switch (op.op)
{
- case CPP_ERROR:
- goto syntax_error;
+ /* These tokens convert into values. */
case CPP_NUMBER:
- /* Push a value onto the stack. */
+ case CPP_CHAR:
+ case CPP_WCHAR:
+ case CPP_NAME:
+ case CPP_HASH:
if (!want_value)
- SYNTAX_ERROR ("missing binary operator");
+ SYNTAX_ERROR2 ("missing binary operator before token \"%s\"",
+ cpp_token_as_text (pfile, token));
want_value = false;
+ op = eval_token (pfile, token);
+ if (op.op == CPP_ERROR)
+ goto syntax_error;
top->value = op.value;
top->unsignedp = op.unsignedp;
continue;
@@ -584,7 +550,20 @@ _cpp_parse_expr (pfile)
if (want_value)
op.op = CPP_UMINUS;
break;
+ case CPP_COLON:
+ if (top == pfile->op_stack || top[-1].op != CPP_QUERY)
+ SYNTAX_ERROR (" ':' without preceding '?'");
+ break;
+ case CPP_OTHER:
+ if (ISGRAPH (token->val.c))
+ SYNTAX_ERROR2 ("invalid character '%c' in #if", token->val.c);
+ else
+ SYNTAX_ERROR2 ("invalid character '\\%03o' in #if", token->val.c);
+
default:
+ if ((int) op.op <= (int) CPP_EQ || (int) op.op >= (int) CPP_PLUS_EQ)
+ SYNTAX_ERROR2 ("token \"%s\" is not valid in #if expressions",
+ cpp_token_as_text (pfile, token));
break;
}
@@ -592,11 +571,13 @@ _cpp_parse_expr (pfile)
if (optab[op.op].flags & NO_L_OPERAND)
{
if (!want_value)
- SYNTAX_ERROR2 ("missing binary operator before '%s'",
- op_as_text (pfile, op.op));
+ SYNTAX_ERROR2 ("missing binary operator before token \"%s\"",
+ cpp_token_as_text (pfile, token));
}
else if (want_value)
{
+ /* Ordering here is subtle and intended to favour the
+ missing parenthesis diagnostics over alternatives. */
if (op.op == CPP_CLOSE_PAREN)
{
if (top->op == CPP_OPEN_PAREN)
@@ -606,19 +587,20 @@ _cpp_parse_expr (pfile)
SYNTAX_ERROR ("#if with no expression");
if (top->op != CPP_EOF && top->op != CPP_OPEN_PAREN)
SYNTAX_ERROR2 ("operator '%s' has no right operand",
- op_as_text (pfile, top->op));
+ cpp_token_as_text (pfile, prev_token));
}
top = reduce (pfile, top, op.op);
if (!top)
goto syntax_error;
+ if (op.op == CPP_EOF)
+ break;
+
switch (op.op)
{
case CPP_CLOSE_PAREN:
continue;
- case CPP_EOF:
- goto done;
case CPP_OR_OR:
if (top->value)
pfile->state.skip_eval++;
@@ -646,7 +628,6 @@ _cpp_parse_expr (pfile)
top->op = op.op;
}
-done:
/* The controlling macro expression is only valid if we called lex 3
times: <!> <defined expression> and <EOF>. push_conditional ()
checks that we are at top-of-file. */
@@ -693,8 +674,7 @@ reduce (pfile, top, op)
switch (top[1].op)
{
default:
- cpp_error (pfile, DL_ICE, "impossible operator '%s'",
- op_as_text (pfile, top[1].op));
+ cpp_error (pfile, DL_ICE, "impossible operator '%u'", top[1].op);
return 0;
case CPP_NOT: UNARY(!); break;
@@ -806,11 +786,6 @@ reduce (pfile, top, op)
cpp_error (pfile, DL_ERROR, "'?' without following ':'");
return 0;
case CPP_COLON:
- if (top->op != CPP_QUERY)
- {
- cpp_error (pfile, DL_ERROR, " ':' without preceding '?'");
- return 0;
- }
top--;
if (top->value) pfile->state.skip_eval--;
top->value = top->value ? v1 : v2;
@@ -848,22 +823,4 @@ _cpp_expand_op_stack (pfile)
(n * 2 + 20) * sizeof (struct op));
return pfile->op_stack + n;
-}
-
-/* Output OP as text for diagnostics. */
-static const unsigned char *
-op_as_text (pfile, op)
- cpp_reader *pfile;
- enum cpp_ttype op;
-{
- cpp_token token;
-
- if (op == CPP_UPLUS)
- op = CPP_PLUS;
- else if (op == CPP_UMINUS)
- op = CPP_MINUS;
-
- token.type = op;
- token.flags = 0;
- return cpp_token_as_text (pfile, &token);
}
Index: cpphash.h
===================================================================
RCS file: /cvs/gcc/gcc/gcc/cpphash.h,v
retrieving revision 1.146
diff -u -p -r1.146 cpphash.h
--- cpphash.h 28 Apr 2002 19:42:30 -0000 1.146
+++ cpphash.h 28 Apr 2002 21:13:24 -0000
@@ -413,7 +413,7 @@ extern void _cpp_init_tokenrun PARAMS (
extern void _cpp_maybe_push_include_file PARAMS ((cpp_reader *));
/* In cpplib.c */
-extern int _cpp_test_assertion PARAMS ((cpp_reader *, int *));
+extern int _cpp_test_assertion PARAMS ((cpp_reader *, unsigned int *));
extern int _cpp_handle_directive PARAMS ((cpp_reader *, int));
extern void _cpp_define_builtin PARAMS ((cpp_reader *, const char *));
extern void _cpp_do__Pragma PARAMS ((cpp_reader *));
Index: cpplib.c
===================================================================
RCS file: /cvs/gcc/gcc/gcc/cpplib.c,v
retrieving revision 1.299
diff -u -p -r1.299 cpplib.c
--- cpplib.c 28 Apr 2002 19:42:30 -0000 1.299
+++ cpplib.c 28 Apr 2002 21:13:33 -0000
@@ -1652,7 +1652,7 @@ find_answer (node, candidate)
int
_cpp_test_assertion (pfile, value)
cpp_reader *pfile;
- int *value;
+ unsigned int *value;
{
struct answer *answer;
cpp_hashnode *node;
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