baa2a973bd
http://clang.llvm.org/docs/AttributeReference.html#nonnull _Nonnull is similar to the nonnull attribute in that it will instruct compilers to warn the user if it can prove that a null argument is being passed. Unlike the nonnull attribute, this annotation indicated that a value *should not* be null, not that it *cannot* be null, or even that the behavior is undefined. The important distinction is that the optimizer will perform surprising optimizations like the following: void foo(void*) __attribute__(nonnull, 1); int bar(int* p) { foo(p); // The following null check will be elided because nonnull // attribute means that, since we call foo with p, p can be // assumed to not be null. Thus this will crash if we are called // with a null pointer. if (src != NULL) { return *p; } return 0; } int main() { return bar(NULL); } Note that by doing this we are no longer attaching any sort of attribute for GCC (GCC doesn't support attaching nonnull directly to a parameter, only to the function and naming the arguments positionally). This means we won't be getting a warning for this case from GCC any more. People that listen to warnings tend to use clang anyway, and we're quickly moving toward that as the default, so this seems to be an acceptable tradeoff. Change-Id: Ie05fe7cec2f19a082c1defb303f82bcf9241b88d
82 lines
2.7 KiB
C
82 lines
2.7 KiB
C
/*
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* Copyright (C) 2008 The Android Open Source Project
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* All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* * Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* * Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in
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* the documentation and/or other materials provided with the
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* distribution.
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*
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* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
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* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
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* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
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* FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
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* COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
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* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
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* BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
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* OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
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* AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
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* OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
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* OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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*/
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#ifndef __DLFCN_H__
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#define __DLFCN_H__
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#include <sys/cdefs.h>
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__BEGIN_DECLS
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typedef struct {
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const char *dli_fname; /* Pathname of shared object that
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contains address */
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void *dli_fbase; /* Address at which shared object
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is loaded */
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const char *dli_sname; /* Name of nearest symbol with address
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lower than addr */
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void *dli_saddr; /* Exact address of symbol named
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in dli_sname */
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} Dl_info;
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extern void* dlopen(const char* filename, int flag);
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extern int dlclose(void* handle);
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extern const char* dlerror(void);
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extern void* dlsym(void* handle, const char* _Nonnull symbol);
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extern void* dlvsym(void* handle, const char* _Nonnull symbol, const char* _Nonnull version)
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__INTRODUCED_IN(24);
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extern int dladdr(const void* addr, Dl_info *info);
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enum {
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#if defined(__LP64__)
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RTLD_NOW = 2,
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#else
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RTLD_NOW = 0,
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#endif
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RTLD_LAZY = 1,
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RTLD_LOCAL = 0,
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#if defined(__LP64__)
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RTLD_GLOBAL = 0x00100,
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#else
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RTLD_GLOBAL = 2,
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#endif
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RTLD_NOLOAD = 4,
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RTLD_NODELETE = 0x01000,
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};
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#if defined (__LP64__)
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#define RTLD_DEFAULT ((void*) 0)
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#define RTLD_NEXT ((void*) -1L)
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#else
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#define RTLD_DEFAULT ((void*) 0xffffffff)
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#define RTLD_NEXT ((void*) 0xfffffffe)
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#endif
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__END_DECLS
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#endif /* __DLFCN_H */
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