159 lines
4.9 KiB
C
159 lines
4.9 KiB
C
/*
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* \brief Stub for compiling GCC support libraries without libc
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* \author Norman Feske
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* \date 2011-08-31
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*
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* The target components of GCC tool chains (i.e. libsupc++, libgcc_eh, and
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* libstdc++) depend on the presence of libc includes. For this reason, a C
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* library for the target platform is normally regarded as a prerequisite for
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* building a complete tool chain. However, for low-level operating-system
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* code, this prerequisite is not satisfied.
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*
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* There are two traditional solutions to this problem. The first is to leave
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* out those target components from the tool chain and live without full C++
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* support (using '-fno-rtti' and '-fno-exceptions'). Because Genode relies on
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* such C++ features however, this is no option. The other traditional solution
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* is to use a tool chain compiled for a different target platform such as
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* Linux. However, this approach calls for subtle problems because the target
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* components are compiled against glibc and make certain presumptions about
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* the underlying OS environment. E.g., the 'libstdc++' library of a Linux tool
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* chain contains references to glibc's 'stderr' symbol, which does not exist
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* on Genode's libc derived from FreeBSD. More critical assumptions are related
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* to the mechanism used for thread-local storage.
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*
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* This header file overcomes these problems by providing all function
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* prototypes and type declarations that are mandatory for compiling GCC's
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* target components. Using this libc stub, all GCC target components can be
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* built without the need for additional libc support. Of course, for actually
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* using these target components, the target OS has to provide the
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* implementation of a small subset of functions declared herein. On Genode,
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* this subset is provided by the 'cxx' library.
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*
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* The code of the target components expects usual C header file names such as
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* 'stdio.h'. It does not include 'libgcc_libc_stub.h'. By creating symlinks
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* for all those file names pointing to this file, we ensure that this file is
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* always included on the first occurrence of the inclusion of any libc header
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* file. The set of symlinks pointing to this libc stub are created
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* automatically by the 'tool_chain' script.
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*/
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/*
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* Copyright (C) 2011-2013 Genode Labs GmbH
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*
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* This file is part of the Genode OS framework, which is distributed
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* under the terms of the GNU General Public License version 2.
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*/
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#ifndef _LINK_H_
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#define _LINK_H_
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#include <stddef.h>
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/*****************
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** sys/types.h **
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*****************/
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#ifdef _LP64
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typedef signed char __int8_t;
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typedef signed short __int16_t;
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typedef signed int __int32_t;
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typedef signed long __int64_t;
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typedef unsigned char __uint8_t;
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typedef unsigned short __uint16_t;
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typedef unsigned int __uint32_t;
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typedef unsigned long __uint64_t;
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#else /* _LP64 */
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typedef signed char __int8_t;
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typedef signed short __int16_t;
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typedef signed long __int32_t;
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typedef unsigned char __uint8_t;
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typedef unsigned short __uint16_t;
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typedef unsigned long __uint32_t;
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#ifndef __STRICT_ANSI__
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typedef signed long long __int64_t;
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typedef unsigned long long __uint64_t;
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#endif /* __STRICT_ANSI__ */
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#endif /* _LP64 */
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/***********
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** elf.h **
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***********/
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/*
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* The following defines and types are solely needed to compile libgcc's
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* 'unwind-dw2-fde-glibc.c' in libc mode. This is needed because Genode's
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* dynamic linker relies on the the "new" exception mechanism, which is not
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* compiled-in when compiling libgcc with the 'inhibit_libc' flag.
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*
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* The following types are loosely based on glibc's 'link.h' and 'elf.h'.
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*/
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typedef __uint32_t Elf64_Word;
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typedef __uint64_t Elf64_Addr;
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typedef __uint64_t Elf64_Xword;
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typedef __uint64_t Elf64_Off;
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typedef __uint16_t Elf64_Half;
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typedef struct
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{
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Elf64_Word p_type;
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Elf64_Word p_flags;
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Elf64_Off p_offset;
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Elf64_Addr p_vaddr;
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Elf64_Addr p_paddr;
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Elf64_Xword p_filesz;
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Elf64_Xword p_memsz;
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Elf64_Xword p_align;
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} Elf64_Phdr;
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typedef __uint32_t Elf32_Word;
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typedef __uint32_t Elf32_Addr;
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typedef __uint64_t Elf32_Xword;
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typedef __uint32_t Elf32_Off;
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typedef __uint16_t Elf32_Half;
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typedef struct
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{
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Elf32_Word p_type;
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Elf32_Off p_offset;
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Elf32_Addr p_vaddr;
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Elf32_Addr p_paddr;
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Elf32_Word p_filesz;
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Elf32_Word p_memsz;
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Elf32_Word p_flags;
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Elf32_Word p_align;
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} Elf32_Phdr;
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#define PT_LOAD 1
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#define PT_DYNAMIC 2
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#define PT_LOOS 0x60000000
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/************
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** link.h **
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************/
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/* definitions according to glibc */
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#ifdef _LP64
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#define ElfW(type) Elf64_##type
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#else
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#define ElfW(type) Elf32_##type
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#endif /* _LP64 */
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struct dl_phdr_info
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{
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ElfW(Addr) dlpi_addr;
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const char *dlpi_name;
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const ElfW(Phdr) *dlpi_phdr;
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ElfW(Half) dlpi_phnum;
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unsigned long long int dlpi_adds;
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unsigned long long int dlpi_subs;
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size_t dlpi_tls_modid;
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void *dlpi_tls_data;
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};
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extern int dl_iterate_phdr(int (*__callback) (struct dl_phdr_info *,
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size_t, void *), void *__data);
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#endif /* _LINK_H_ */
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