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[PATCH] PR preprocessor/61817 - Fix location of tokens in built-in macro expansion list
- From: Dodji Seketeli <dodji at redhat dot com>
- To: GCC Patches <gcc-patches at gcc dot gnu dot org>
- Cc: Jason Merrill <jason at redhat dot com>, Tom Tromey <tromey at redhat dot com>, Nicholas Ormrod <nicholas dot ormrod at hotmail dot com>
- Date: Wed, 16 Jul 2014 16:08:39 +0200
- Subject: [PATCH] PR preprocessor/61817 - Fix location of tokens in built-in macro expansion list
- Authentication-results: sourceware.org; auth=none
Hello,
Consider this function-like macro definition in this inc.h file:
------------------->inc.h<-------------------
#define F() const int line = __LINE__
------------------->8<-----------------------
Now consider its use in a file test.c:
------------------>cat -n test.c<----------------
1 #include "inc.h"
2
3 void
4 foo()
5 {
6 F
7 (
8 )
9 ;
10 }
------------------->8<---------------------
Running test.c through cc1 -quiet -E yields:
--------------------->8<--------------------
# 1 "test.c"
# 1 "<built-in>"
# 1 "<command-line>"
# 1 "/usr/include/stdc-predef.h" 1 3 4
# 1 "<command-line>" 2
# 1 "test.c"
# 1 "inc.h" 1
# 2 "test.c" 2
void
foo()
{
const int line =
8
;
}
--------------------->8<----------------------
Note how tokens "const", "int", "line" and "=" are all on the same
line (line 6) as the expansion point of the function-like F() macro,
but how the token "8", resulting from the expansion of the built-in
macro __FILE__ is on the same line as the closing parenthesis of the
invocation of F().
This is the problem. The result of the __FILE__ macro should be "6"
and should be on the same line (line 6) as the other tokens of the
expansion-list of F().
This issue actually holds for the expansion of all built-in macros.
So more generelly, I would describe the issue as such:
When expanded in a function-like macro, the location of resulting
tokens of a built-in macro is set to the closing parenthesis of the
enclosing function-like macro invocation, rather than being set to the
location of the expansion point of the invocation the enclosing
function-like macro.
I think the problem is that enter_macro_context() is passed the
location of the expansion point of the macro that is about to be
expanded. But when that macro is built-in, builtin_macro() that is
then called by enter_macro_context() doesn't use the macro expansion
point location. Rather, builtin_macro uses the location of the
closing parenthesis of the enclosing function-like macro invocation
or, more generally, the location of the previous token in the stream.
The patch proposes to pass builtin_macro() the expansion point
location that enter_macro_context() already knows about and use that
to set the location of the resulting token.
Also, for the particular case of __LINE__, it makes that built-in expand
to the line number or that expansion point.
With the patch applied, the output becomes:
$ ./cc1 -quiet -E test.c
# 1 "../../../master/test/test.c"
# 1 "<built-in>"
# 1 "<command-line>"
# 1 "/usr/include/stdc-predef.h" 1 3 4
# 1 "<command-line>" 2
# 1 "../../../master/test/test.c"
# 1 "../../../master/test/inc.h" 1
# 2 "../../../master/test/test.c" 2
void
foo()
{
const int line = 6
;
}
$
Bootstrapped and tested against trunk on x86_64-unknown-linux-gnu.
libcpp/
* macro.c (_cpp_builtin_macro_text): Honor the
cpp_reader::forced_token_location_p data member to force the value
__LINE__ expands to accordlingly.
(builtin_macro): Take the expansion point location as parameter.
Use cpp_force_token_locations() to set the location of the
resulting token to that expansion point location.
(enter_macro_context): Pass the expansion point locatoin to
builtin_macro.
gcc/testsuite/
* gcc.dg/cpp/builtin-macro-{0,1}.c: New test files.
Signed-off-by: Dodji Seketeli <dodji@redhat.com>
---
gcc/testsuite/gcc.dg/cpp/builtin-macro-0.c | 18 +++++++++++
gcc/testsuite/gcc.dg/cpp/builtin-macro-1.c | 30 +++++++++++++++++
libcpp/macro.c | 52 ++++++++++++++++++++++++------
3 files changed, 90 insertions(+), 10 deletions(-)
create mode 100644 gcc/testsuite/gcc.dg/cpp/builtin-macro-0.c
create mode 100644 gcc/testsuite/gcc.dg/cpp/builtin-macro-1.c
diff --git a/gcc/testsuite/gcc.dg/cpp/builtin-macro-0.c b/gcc/testsuite/gcc.dg/cpp/builtin-macro-0.c
new file mode 100644
index 0000000..f57dd5b
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/cpp/builtin-macro-0.c
@@ -0,0 +1,18 @@
+/* Origin: PR preprocessor/61817
+
+ In this test case, the diagnostic (happening for tokens resulting
+ from the expansion of the built-in token __FILE__) must point to the
+ expansion point of the enclosing function-like macro invocation.
+
+ { dg-do compile }
+ { dg-options "-no-integrated-cpp" } */
+
+#define F() static const char* __FILE__
+
+void
+foo ()
+{
+ F /* { dg-error "expected identifier" } */
+ (
+ );
+}
diff --git a/gcc/testsuite/gcc.dg/cpp/builtin-macro-1.c b/gcc/testsuite/gcc.dg/cpp/builtin-macro-1.c
new file mode 100644
index 0000000..280797b
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/cpp/builtin-macro-1.c
@@ -0,0 +1,30 @@
+/* Origin: PR preprocessor/61817
+
+ This test detects that the __LINE__ built-in macro expands to the
+ line number of the expansion point of the function-like macro in
+ which it's exanded. So if you change the content of this file,
+ please adjust the test to reflect the new lines layout.
+
+ { dg-do run }
+ { dg-options -no-integrated-cpp } */
+
+#include <assert.h>
+
+#define F() static const int line = __LINE__;
+
+void
+foo ()
+{
+ F /* the__LINE__ macro should expand to this line number. */
+ (
+ );
+
+ assert (line == 18);
+}
+
+int
+main ()
+{
+ foo();
+ return 0;
+}
diff --git a/libcpp/macro.c b/libcpp/macro.c
index 3b8fa40..b72ce2b 100644
--- a/libcpp/macro.c
+++ b/libcpp/macro.c
@@ -84,7 +84,7 @@ struct macro_arg_token_iter
static int enter_macro_context (cpp_reader *, cpp_hashnode *,
const cpp_token *, source_location);
-static int builtin_macro (cpp_reader *, cpp_hashnode *);
+static int builtin_macro (cpp_reader *, cpp_hashnode *, source_location);
static void push_ptoken_context (cpp_reader *, cpp_hashnode *, _cpp_buff *,
const cpp_token **, unsigned int);
static void push_extended_tokens_context (cpp_reader *, cpp_hashnode *,
@@ -309,10 +309,29 @@ _cpp_builtin_macro_text (cpp_reader *pfile, cpp_hashnode *node)
/* If __LINE__ is embedded in a macro, it must expand to the
line of the macro's invocation, not its definition.
Otherwise things like assert() will not work properly. */
- number = linemap_get_expansion_line (pfile->line_table,
- CPP_OPTION (pfile, traditional)
- ? pfile->line_table->highest_line
- : pfile->cur_token[-1].src_loc);
+ if (pfile->forced_token_location_p)
+ {
+ /* We were asked to force the location of the resulting
+ token to have a certain value. */
+ if (pfile->context->tokens_kind == TOKENS_KIND_EXTENDED)
+ /* We are tracking macro locations. So this location
+ might be virtual. In that case, unwind that location
+ to the first location in the source code, towards the
+ expansion point of the original macro that triggered
+ the expansion. */
+ number =
+ linemap_unwind_to_first_non_reserved_loc (pfile->line_table,
+ *pfile->forced_token_location_p,
+ NULL);
+ else
+ number = *pfile->forced_token_location_p;
+ number = linemap_get_expansion_line (pfile->line_table, number);
+ }
+ else
+ number = linemap_get_expansion_line (pfile->line_table,
+ CPP_OPTION (pfile, traditional)
+ ? pfile->line_table->highest_line
+ : pfile->cur_token[-1].src_loc);
break;
/* __STDC__ has the value 1 under normal circumstances.
@@ -398,10 +417,14 @@ _cpp_builtin_macro_text (cpp_reader *pfile, cpp_hashnode *node)
/* Convert builtin macros like __FILE__ to a token and push it on the
context stack. Also handles _Pragma, for which a new token may not
- be created. Returns 1 if it generates a new token context, 0 to
- return the token to the caller. */
+ be created. NODE is the built-in macro to consider.
+ EXPANSION_LOCATION is the location of the expansion of the macro
+ NODE. Note that this location can be virtual if we are tracking
+ macro locations. Returns 1 if it generates a new token context, 0
+ to return the token to the caller. */
static int
-builtin_macro (cpp_reader *pfile, cpp_hashnode *node)
+builtin_macro (cpp_reader *pfile, cpp_hashnode *node,
+ source_location expansion_location)
{
const uchar *buf;
size_t len;
@@ -417,6 +440,13 @@ builtin_macro (cpp_reader *pfile, cpp_hashnode *node)
return _cpp_do__Pragma (pfile);
}
+ /* Make sure the location of the token resulting from the expansion
+ of the built-in token is the location of the expansion point that
+ we are passed. As a result, _cpp_builtin_macro_text() and
+ _cpp_lex_direct() that are called below will set the location of
+ their resulting token to this expansion point. */
+ cpp_force_token_locations (pfile, &expansion_location);
+
buf = _cpp_builtin_macro_text (pfile, node);
len = ustrlen (buf);
nbuf = (char *) alloca (len + 1);
@@ -429,6 +459,8 @@ builtin_macro (cpp_reader *pfile, cpp_hashnode *node)
/* Set pfile->cur_token as required by _cpp_lex_direct. */
pfile->cur_token = _cpp_temp_token (pfile);
cpp_token *token = _cpp_lex_direct (pfile);
+ cpp_stop_forcing_token_locations (pfile);
+
if (pfile->context->tokens_kind == TOKENS_KIND_EXTENDED)
{
/* We are tracking tokens resulting from macro expansion.
@@ -439,7 +471,7 @@ builtin_macro (cpp_reader *pfile, cpp_hashnode *node)
_cpp_buff *token_buf = tokens_buff_new (pfile, 1, &virt_locs);
const line_map * map =
linemap_enter_macro (pfile->line_table, node,
- token->src_loc, 1);
+ expansion_location, 1);
tokens_buff_add_token (token_buf, virt_locs, token,
pfile->line_table->builtin_location,
pfile->line_table->builtin_location,
@@ -1212,7 +1244,7 @@ enter_macro_context (cpp_reader *pfile, cpp_hashnode *node,
pfile->about_to_expand_macro_p = false;
/* Handle built-in macros and the _Pragma operator. */
- return builtin_macro (pfile, node);
+ return builtin_macro (pfile, node, location);
}
/* De-allocate the memory used by BUFF which is an array of instances
--
Dodji