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PATCH: Adds a __COUNTER__ macro.
- From: "Ollie Wild" <aaw at google dot com>
- To: "GCC Patches" <gcc-patches at gcc dot gnu dot org>, tromey at redhat dot com
- Cc: "Dave Korn" <dave dot korn at artimi dot com>, "Basile STARYNKEVITCH" <basile at starynkevitch dot net>, "Ian Lance Taylor" <iant at google dot com>
- Date: Wed, 23 May 2007 14:34:11 -0700
- Subject: PATCH: Adds a __COUNTER__ macro.
This patch adds a builtin __COUNTER__ macro which expands to
incrementing integral values starting from 0. In conjunction with the
'##' operator, this is useful for generating unique identifiers. Per
my comments at http://gcc.gnu.org/ml/gcc-patches/2007-05/msg01488.html,
this does not include some additional logic to integrate with the
pending -fdirectives-only patch.
Tested with a full bootstrap and testsuite run on i686-pc-linux-gnu.
Ollie
:ADDPATCH libcpp:
2007-05-23 Ollie Wild <aaw@google.com>
* macro.c (_cpp_builtin_macro_text): Handle BT_COUNTER.
* pch.c (cpp_write_pch_deps): Save __COUNTER__ state.
(cpp_write_pch_state): Save __COUNTER__ state.
(cpp_valid_state): Check valid __COUNTER__ state.
(cpp_read_state): Read new __COUNTER__ state.
* include/cpplib.h (enum builtin_type): Add BT_COUNTER enumerator.
* init.c (builtin_array): Add __COUNTER__/BT_COUNTER.
* internal.h (struct cpp_reader): Add counter member.
2007-05-23 Ollie Wild <aaw@google.com>
* doc/cpp.texi (Common Predefined Macros): Add __COUNTER__
description.
2007-05-23 Ollie Wild <aaw@google.com>
* gcc.dg/cpp/counter-1.c: New test.
* gcc.dg/pch/counter-1.c: New test.
* gcc.dg/pch/counter-1.hs: New file.
* gcc.dg/pch/counter-2.c: New test.
* gcc.dg/pch/counter-2.hs: New file.
* gcc.dg/pch/counter-3.c: New test.
* gcc.dg/pch/counter-3.hs: New file.
diff --git a/gcc/doc/cpp.texi b/gcc/doc/cpp.texi
index e6786cf..54941a9 100644
--- a/gcc/doc/cpp.texi
+++ b/gcc/doc/cpp.texi
@@ -1917,6 +1917,13 @@ underscores.
@table @code
+@item __COUNTER__
+This macro expands to sequential integral values starting from 0. In
+conjuction with the @code{##} operator, this provides a convenient means to
+generate unique identifiers. Care must be taken to ensure that
+@code{__COUNTER__} is not expanded prior to inclusion of precompiled headers
+which use it. Otherwise, the precompiled headers will not be used.
+
@item __GNUC__
@itemx __GNUC_MINOR__
@itemx __GNUC_PATCHLEVEL__
diff --git a/gcc/testsuite/gcc.dg/cpp/counter-1.c b/gcc/testsuite/gcc.dg/cpp/counter-1.c
new file mode 100644
index 0000000..80d8b78
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/cpp/counter-1.c
@@ -0,0 +1,20 @@
+/* Copyright (C) 2007 Free Software Foundation
+ Contributed by Ollie Wild <aaw@google.com> */
+
+/* { dg-do preprocess } */
+
+/* Tests __COUNTER__ macro is correctly expanded. */
+
+#define counter __COUNTER__
+
+#if __COUNTER__ != 0
+#error __COUNTER__ != 0
+#endif
+
+#if counter != 1
+#error counter != 1
+#endif
+
+#if __COUNTER__ != 2
+#error __COUNTER__ != 2
+#endif
diff --git a/gcc/testsuite/gcc.dg/pch/counter-1.c b/gcc/testsuite/gcc.dg/pch/counter-1.c
new file mode 100644
index 0000000..79cea88
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/pch/counter-1.c
@@ -0,0 +1,9 @@
+/* Copyright (C) 2007 Free Software Foundation
+ Contributed by Ollie Wild <aaw@google.com> */
+
+#include "counter-1.h"
+
+int main(void)
+{
+ return __COUNTER__;
+}
diff --git a/gcc/testsuite/gcc.dg/pch/counter-1.hs b/gcc/testsuite/gcc.dg/pch/counter-1.hs
new file mode 100644
index 0000000..c3d2ce7
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/pch/counter-1.hs
@@ -0,0 +1,5 @@
+/* Copyright (C) 2007 Free Software Foundation
+ Contributed by Ollie Wild <aaw@google.com> */
+
+static unsigned offset[] = {__COUNTER__, __COUNTER__, __COUNTER__};
+#define counter __COUNTER__
diff --git a/gcc/testsuite/gcc.dg/pch/counter-2.c b/gcc/testsuite/gcc.dg/pch/counter-2.c
new file mode 100644
index 0000000..7bbde23
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/pch/counter-2.c
@@ -0,0 +1,15 @@
+/* Copyright (C) 2007 Free Software Foundation
+ Contributed by Ollie Wild <aaw@google.com> */
+
+/* { dg-options "-I. -Winvalid-pch" } */
+
+#if __COUNTER__ != 0
+#error __COUNTER__ != 0
+#endif
+
+#include "counter-2.h"/* { dg-error "`__COUNTER__' is invalid|No such file|they were invalid" } */
+
+int main(void)
+{
+ return __COUNTER__;
+}
diff --git a/gcc/testsuite/gcc.dg/pch/counter-2.hs b/gcc/testsuite/gcc.dg/pch/counter-2.hs
new file mode 100644
index 0000000..63b8a2b
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/pch/counter-2.hs
@@ -0,0 +1,4 @@
+/* Copyright (C) 2007 Free Software Foundation
+ Contributed by Ollie Wild <aaw@google.com> */
+
+static int i = __COUNTER__;
diff --git a/gcc/testsuite/gcc.dg/pch/counter-3.c b/gcc/testsuite/gcc.dg/pch/counter-3.c
new file mode 100644
index 0000000..8279205
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/pch/counter-3.c
@@ -0,0 +1,13 @@
+/* Copyright (C) 2007 Free Software Foundation
+ Contributed by Ollie Wild <aaw@google.com> */
+
+#if __COUNTER__ != 0
+#error __COUNTER__ != 0
+#endif
+
+#include "counter-3.h"
+
+int main(void)
+{
+ return __COUNTER__;
+}
diff --git a/gcc/testsuite/gcc.dg/pch/counter-3.hs b/gcc/testsuite/gcc.dg/pch/counter-3.hs
new file mode 100644
index 0000000..19039c8
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/pch/counter-3.hs
@@ -0,0 +1,4 @@
+/* Copyright (C) 2007 Free Software Foundation
+ Contributed by Ollie Wild <aaw@google.com> */
+
+#define counter __COUNTER__
diff --git a/libcpp/include/cpplib.h b/libcpp/include/cpplib.h
index b293998..ff5292e 100644
--- a/libcpp/include/cpplib.h
+++ b/libcpp/include/cpplib.h
@@ -555,7 +555,8 @@ enum builtin_type
BT_TIME, /* `__TIME__' */
BT_STDC, /* `__STDC__' */
BT_PRAGMA, /* `_Pragma' operator */
- BT_TIMESTAMP /* `__TIMESTAMP__' */
+ BT_TIMESTAMP, /* `__TIMESTAMP__' */
+ BT_COUNTER /* `__COUNTER__' */
};
#define CPP_HASHNODE(HNODE) ((cpp_hashnode *) (HNODE))
diff --git a/libcpp/init.c b/libcpp/init.c
index db697e9..71583df 100644
--- a/libcpp/init.c
+++ b/libcpp/init.c
@@ -310,6 +310,7 @@ static const struct builtin builtin_array[] =
B("__BASE_FILE__", BT_BASE_FILE),
B("__LINE__", BT_SPECLINE),
B("__INCLUDE_LEVEL__", BT_INCLUDE_LEVEL),
+ B("__COUNTER__", BT_COUNTER),
/* Keep builtins not used for -traditional-cpp at the end, and
update init_builtins() if any more are added. */
B("_Pragma", BT_PRAGMA),
diff --git a/libcpp/internal.h b/libcpp/internal.h
index 9395f6a..d000cfd 100644
--- a/libcpp/internal.h
+++ b/libcpp/internal.h
@@ -452,6 +452,9 @@ struct cpp_reader
/* A saved list of the defined macros, for dependency checking
of precompiled headers. */
struct cpp_savedstate *savedstate;
+
+ /* Next value of __COUNTER__ macro. */
+ unsigned int counter;
};
/* Character classes. Based on the more primitive macros in safe-ctype.h.
diff --git a/libcpp/macro.c b/libcpp/macro.c
index 748635f..cfdf595 100644
--- a/libcpp/macro.c
+++ b/libcpp/macro.c
@@ -263,6 +263,10 @@ _cpp_builtin_macro_text (cpp_reader *pfile, cpp_hashnode *node)
else
result = pfile->time;
break;
+
+ case BT_COUNTER:
+ number = pfile->counter++;
+ break;
}
if (result == NULL)
diff --git a/libcpp/pch.c b/libcpp/pch.c
index cc23b4e..09373a2 100644
--- a/libcpp/pch.c
+++ b/libcpp/pch.c
@@ -337,6 +337,14 @@ cpp_write_pch_deps (cpp_reader *r, FILE *f)
/* Free the saved state. */
free (ss);
r->savedstate = NULL;
+
+ /* Save the next value of __COUNTER__. */
+ if (fwrite (&r->counter, sizeof (r->counter), 1, f) != 1)
+ {
+ cpp_errno (r, CPP_DL_ERROR, "while writing precompiled header");
+ return -1;
+ }
+
return 0;
}
@@ -361,6 +369,15 @@ cpp_write_pch_state (cpp_reader *r, FILE *f)
return -1;
}
+ /* Save the next __COUNTER__ value. When we include a precompiled header,
+ we need to start at the offset we would have if the header had been
+ included normally. */
+ if (fwrite (&r->counter, sizeof (r->counter), 1, f) != 1)
+ {
+ cpp_errno (r, CPP_DL_ERROR, "while writing precompiled header");
+ return -1;
+ }
+
return 0;
}
@@ -423,6 +440,7 @@ cpp_valid_state (cpp_reader *r, const char *name, int fd)
struct ht_node_list nl = { 0, 0, 0 };
unsigned char *first, *last;
unsigned int i;
+ unsigned int counter;
/* Read in the list of identifiers that must be defined
Check that they are defined in the same way. */
@@ -524,7 +542,23 @@ cpp_valid_state (cpp_reader *r, const char *name, int fd)
}
free(nl.defs);
+ nl.defs = NULL;
free (undeftab);
+ undeftab = NULL;
+
+ /* Read in the next value of __COUNTER__.
+ Check that (a) __COUNTER__ was not used in the pch or (b) __COUNTER__
+ has not been used in this translation unit. */
+ if (read (fd, &counter, sizeof (counter)) != sizeof (counter))
+ goto error;
+ if (counter && r->counter)
+ {
+ if (CPP_OPTION (r, warn_invalid_pch))
+ cpp_error (r, CPP_DL_WARNING_SYSHDR,
+ "%s: not used because `__COUNTER__' is invalid",
+ name);
+ goto fail;
+ }
/* We win! */
return 0;
@@ -631,6 +665,7 @@ cpp_read_state (cpp_reader *r, const char *name, FILE *f,
{
size_t i;
struct lexer_state old_state;
+ unsigned int counter;
/* Restore spec_nodes, which will be full of references to the old
hashtable entries and so will now be invalid. */
@@ -690,6 +725,12 @@ cpp_read_state (cpp_reader *r, const char *name, FILE *f,
if (! _cpp_read_file_entries (r, f))
goto error;
+ if (fread (&counter, sizeof (counter), 1, f) != 1)
+ goto error;
+
+ if (!r->counter)
+ r->counter = counter;
+
return 0;
error: