Files
binutils-gdb/gdb/common/common-utils.h
Simon Marchi 8172f16b5b Poison XNEW and friends for types that should use new/delete
This patch (finally!) makes it so that trying to use XNEW with a type
that requires "new" will cause a compilation error.  The criterion I
initially used to allow a type to use XNEW (which calls malloc in the
end) was std::is_trivially_constructible, but then realized that gcc 4.8
did not have it.  Instead, I went with:

  using IsMallocatable = std::is_pod<T>;

which is just a bit more strict, which doesn't hurt.  A similar thing is
done for macros that free instead of allocated, the criterion is:

  using IsFreeable = gdb::Or<std::is_trivially_destructible<T>, std::is_void<T>>;

Trying to use XNEW on a type that requires new will result in an error
like this:

    In file included from /home/simark/src/binutils-gdb/gdb/common/common-utils.h:26:0,
                     from /home/simark/src/binutils-gdb/gdb/common/common-defs.h:78,
                     from /home/simark/src/binutils-gdb/gdb/defs.h:28,
                     from /home/simark/src/binutils-gdb/gdb/lala.c:1:
    /home/simark/src/binutils-gdb/gdb/common/poison.h: In instantiation of ‘T* xnew() [with T = bar]’:
    /home/simark/src/binutils-gdb/gdb/lala.c:13:3:   required from here
    /home/simark/src/binutils-gdb/gdb/common/poison.h:103:3: error: static assertion failed: Trying to use XNEW with a non-POD data type.  Use operator new instead.
       static_assert (IsMallocatable<T>::value, "Trying to use XNEW with a non-POD\
       ^~~~~~~~~~~~~

Generated-code-wise, it adds one more function call (xnew<T>) when using
XNEW and building with -O0, but it all goes away with optimizations
enabled.

gdb/ChangeLog:

	* common/common-utils.h: Include poison.h.
	(xfree): Remove declaration, add definition with static_assert.
	* common/common-utils.c (xfree): Remove.
	* common/poison.h (IsMallocatable): Define.
	(IsFreeable): Define.
	(free): Delete for non-freeable types.
	(xnew): New.
	(XNEW): Undef and redefine.
	(xcnew): New.
	(XCNEW): Undef and redefine.
	(xdelete): New.
	(XDELETE): Undef and redefine.
	(xnewvec): New.
	(XNEWVEC): Undef and redefine.
	(xcnewvec): New.
	(XCNEWVEC): Undef and redefine.
	(xresizevec): New.
	(XRESIZEVEC): Undef and redefine.
	(xdeletevec): New.
	(XDELETEVEC): Undef and redefine.
	(xnewvar): New.
	(XNEWVAR): Undef and redefine.
	(xcnewvar): New.
	(XCNEWVAR): Undef and redefine.
	(xresizevar): New.
	(XRESIZEVAR): Undef and redefine.
2017-11-24 10:42:25 -05:00

150 lines
4.7 KiB
C++

/* Shared general utility routines for GDB, the GNU debugger.
Copyright (C) 1986-2017 Free Software Foundation, Inc.
This file is part of GDB.
This program is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 3 of the License, or
(at your option) any later version.
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program. If not, see <http://www.gnu.org/licenses/>. */
#ifndef COMMON_UTILS_H
#define COMMON_UTILS_H
#include <string>
#include <vector>
#include "poison.h"
/* If possible, define FUNCTION_NAME, a macro containing the name of
the function being defined. Since this macro may not always be
defined, all uses must be protected by appropriate macro definition
checks (Eg: "#ifdef FUNCTION_NAME").
Version 2.4 and later of GCC define a magical variable `__PRETTY_FUNCTION__'
which contains the name of the function currently being defined.
This is broken in G++ before version 2.6.
C9x has a similar variable called __func__, but prefer the GCC one since
it demangles C++ function names. */
#if (GCC_VERSION >= 2004)
#define FUNCTION_NAME __PRETTY_FUNCTION__
#else
#if defined __STDC_VERSION__ && __STDC_VERSION__ >= 199901L
#define FUNCTION_NAME __func__ /* ARI: func */
#endif
#endif
/* xmalloc(), xrealloc() and xcalloc() have already been declared in
"libiberty.h". */
/* Like xmalloc, but zero the memory. */
void *xzalloc (size_t);
template <typename T>
static void
xfree (T *ptr)
{
static_assert (IsFreeable<T>::value, "Trying to use xfree with a non-POD \
data type. Use operator delete instead.");
if (ptr != NULL)
free (ptr); /* ARI: free */
}
/* Like asprintf and vasprintf, but return the string, throw an error
if no memory. */
char *xstrprintf (const char *format, ...) ATTRIBUTE_PRINTF (1, 2);
char *xstrvprintf (const char *format, va_list ap)
ATTRIBUTE_PRINTF (1, 0);
/* Like snprintf, but throw an error if the output buffer is too small. */
int xsnprintf (char *str, size_t size, const char *format, ...)
ATTRIBUTE_PRINTF (3, 4);
/* Returns a std::string built from a printf-style format string. */
std::string string_printf (const char* fmt, ...)
ATTRIBUTE_PRINTF (1, 2);
/* Like string_printf, but takes a va_list. */
std::string string_vprintf (const char* fmt, va_list args)
ATTRIBUTE_PRINTF (1, 0);
/* Like string_printf, but appends to DEST instead of returning a new
std::string. */
void string_appendf (std::string &dest, const char* fmt, ...)
ATTRIBUTE_PRINTF (2, 3);
/* Like string_appendf, but takes a va_list. */
void string_vappendf (std::string &dest, const char* fmt, va_list args)
ATTRIBUTE_PRINTF (2, 0);
/* Make a copy of the string at PTR with LEN characters
(and add a null character at the end in the copy).
Uses malloc to get the space. Returns the address of the copy. */
char *savestring (const char *ptr, size_t len);
/* The strerror() function can return NULL for errno values that are
out of range. Provide a "safe" version that always returns a
printable string. */
extern char *safe_strerror (int);
/* Return non-zero if the start of STRING matches PATTERN, zero
otherwise. */
static inline int
startswith (const char *string, const char *pattern)
{
return strncmp (string, pattern, strlen (pattern)) == 0;
}
ULONGEST strtoulst (const char *num, const char **trailer, int base);
/* Skip leading whitespace characters in INP, returning an updated
pointer. If INP is NULL, return NULL. */
extern char *skip_spaces (char *inp);
/* A const-correct version of the above. */
extern const char *skip_spaces (const char *inp);
/* Skip leading non-whitespace characters in INP, returning an updated
pointer. If INP is NULL, return NULL. */
extern char *skip_to_space (char *inp);
/* A const-correct version of the above. */
extern const char *skip_to_space (const char *inp);
/* Assumes that V is an argv for a program, and iterates through
freeing all the elements. */
extern void free_vector_argv (std::vector<char *> &v);
/* Given a vector of arguments ARGV, return a string equivalent to
joining all the arguments with a whitespace separating them. */
extern std::string stringify_argv (const std::vector<char *> &argv);
/* Return true if VALUE is in [LOW, HIGH]. */
template <typename T>
static bool
in_inclusive_range (T value, T low, T high)
{
return value >= low && value <= high;
}
#endif