1/* Definitions for systems using the Linux kernel, with or without
2 MMU, using ELF at the compiler level but possibly FLT for final
3 linked executables and shared libraries in some no-MMU cases, and
4 possibly with a choice of libc implementations.
5 Copyright (C) 1995-2025 Free Software Foundation, Inc.
6 Contributed by Eric Youngdale.
7 Modified for stabs-in-ELF by H.J. Lu (hjl@lucon.org).
8
9This file is part of GCC.
10
11GCC is free software; you can redistribute it and/or modify
12it under the terms of the GNU General Public License as published by
13the Free Software Foundation; either version 3, or (at your option)
14any later version.
15
16GCC is distributed in the hope that it will be useful,
17but WITHOUT ANY WARRANTY; without even the implied warranty of
18MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
19GNU General Public License for more details.
20
21Under Section 7 of GPL version 3, you are granted additional
22permissions described in the GCC Runtime Library Exception, version
233.1, as published by the Free Software Foundation.
24
25You should have received a copy of the GNU General Public License and
26a copy of the GCC Runtime Library Exception along with this program;
27see the files COPYING3 and COPYING.RUNTIME respectively. If not, see
28<http://www.gnu.org/licenses/>. */
29
30/* C libraries supported on Linux. */
31#ifdef SINGLE_LIBC
32#define OPTION_GLIBC_P(opts) (DEFAULT_LIBC == LIBC_GLIBC)
33#define OPTION_UCLIBC_P(opts) (DEFAULT_LIBC == LIBC_UCLIBC)
34#define OPTION_BIONIC_P(opts) (DEFAULT_LIBC == LIBC_BIONIC)
35#undef OPTION_MUSL_P
36#define OPTION_MUSL_P(opts) (DEFAULT_LIBC == LIBC_MUSL)
37#else
38#define OPTION_GLIBC_P(opts) ((opts)->x_linux_libc == LIBC_GLIBC)
39#define OPTION_UCLIBC_P(opts) ((opts)->x_linux_libc == LIBC_UCLIBC)
40#define OPTION_BIONIC_P(opts) ((opts)->x_linux_libc == LIBC_BIONIC)
41#undef OPTION_MUSL_P
42#define OPTION_MUSL_P(opts) ((opts)->x_linux_libc == LIBC_MUSL)
43#endif
44#define OPTION_GLIBC OPTION_GLIBC_P (&global_options)
45#define OPTION_UCLIBC OPTION_UCLIBC_P (&global_options)
46#define OPTION_BIONIC OPTION_BIONIC_P (&global_options)
47#undef OPTION_MUSL
48#define OPTION_MUSL OPTION_MUSL_P (&global_options)
49
50#define GNU_USER_TARGET_OS_CPP_BUILTINS() \
51 do { \
52 if (OPTION_GLIBC) \
53 builtin_define ("__gnu_linux__"); \
54 builtin_define_std ("linux"); \
55 builtin_define_std ("unix"); \
56 builtin_assert ("system=linux"); \
57 builtin_assert ("system=unix"); \
58 builtin_assert ("system=posix"); \
59 } while (0)
60
61/* Determine which dynamic linker to use depending on whether GLIBC or
62 uClibc or Bionic or musl is the default C library and whether
63 -muclibc or -mglibc or -mbionic or -mmusl has been passed to change
64 the default. */
65
66#define CHOOSE_DYNAMIC_LINKER1(LIBC1, LIBC2, LIBC3, LIBC4, LD1, LD2, LD3, LD4) \
67 "%{" LIBC2 ":" LD2 ";:%{" LIBC3 ":" LD3 ";:%{" LIBC4 ":" LD4 ";:" LD1 "}}}"
68
69#if DEFAULT_LIBC == LIBC_GLIBC
70#define CHOOSE_DYNAMIC_LINKER(G, U, B, M) \
71 CHOOSE_DYNAMIC_LINKER1 ("mglibc", "muclibc", "mbionic", "mmusl", G, U, B, M)
72#elif DEFAULT_LIBC == LIBC_UCLIBC
73#define CHOOSE_DYNAMIC_LINKER(G, U, B, M) \
74 CHOOSE_DYNAMIC_LINKER1 ("muclibc", "mglibc", "mbionic", "mmusl", U, G, B, M)
75#elif DEFAULT_LIBC == LIBC_BIONIC
76#define CHOOSE_DYNAMIC_LINKER(G, U, B, M) \
77 CHOOSE_DYNAMIC_LINKER1 ("mbionic", "mglibc", "muclibc", "mmusl", B, G, U, M)
78#elif DEFAULT_LIBC == LIBC_MUSL
79#define CHOOSE_DYNAMIC_LINKER(G, U, B, M) \
80 CHOOSE_DYNAMIC_LINKER1 ("mmusl", "mglibc", "muclibc", "mbionic", M, G, U, B)
81#else
82#error "Unsupported DEFAULT_LIBC"
83#endif /* DEFAULT_LIBC */
84
85/* For most targets the following definitions suffice;
86 GLIBC_DYNAMIC_LINKER must be defined for each target using them, or
87 GLIBC_DYNAMIC_LINKER32 and GLIBC_DYNAMIC_LINKER64 for targets
88 supporting both 32-bit and 64-bit compilation. */
89#define UCLIBC_DYNAMIC_LINKER "/lib/ld-uClibc.so.0"
90#define UCLIBC_DYNAMIC_LINKER32 "/lib/ld-uClibc.so.0"
91#define UCLIBC_DYNAMIC_LINKER64 "/lib/ld64-uClibc.so.0"
92#define UCLIBC_DYNAMIC_LINKERX32 "/lib/ldx32-uClibc.so.0"
93#define BIONIC_DYNAMIC_LINKER "/system/bin/linker"
94#define BIONIC_DYNAMIC_LINKER32 "/system/bin/linker"
95#define BIONIC_DYNAMIC_LINKER64 "/system/bin/linker64"
96#define BIONIC_DYNAMIC_LINKERX32 "/system/bin/linkerx32"
97/* Should be redefined for each target that supports musl. */
98#define MUSL_DYNAMIC_LINKER "/dev/null"
99#define MUSL_DYNAMIC_LINKER32 "/dev/null"
100#define MUSL_DYNAMIC_LINKER64 "/dev/null"
101#define MUSL_DYNAMIC_LINKERX32 "/dev/null"
102
103#define GNU_USER_DYNAMIC_LINKER \
104 CHOOSE_DYNAMIC_LINKER (GLIBC_DYNAMIC_LINKER, UCLIBC_DYNAMIC_LINKER, \
105 BIONIC_DYNAMIC_LINKER, MUSL_DYNAMIC_LINKER)
106#define GNU_USER_DYNAMIC_LINKER32 \
107 CHOOSE_DYNAMIC_LINKER (GLIBC_DYNAMIC_LINKER32, UCLIBC_DYNAMIC_LINKER32, \
108 BIONIC_DYNAMIC_LINKER32, MUSL_DYNAMIC_LINKER32)
109#define GNU_USER_DYNAMIC_LINKER64 \
110 CHOOSE_DYNAMIC_LINKER (GLIBC_DYNAMIC_LINKER64, UCLIBC_DYNAMIC_LINKER64, \
111 BIONIC_DYNAMIC_LINKER64, MUSL_DYNAMIC_LINKER64)
112#define GNU_USER_DYNAMIC_LINKERX32 \
113 CHOOSE_DYNAMIC_LINKER (GLIBC_DYNAMIC_LINKERX32, UCLIBC_DYNAMIC_LINKERX32, \
114 BIONIC_DYNAMIC_LINKERX32, MUSL_DYNAMIC_LINKERX32)
115
116/* Whether we have Bionic libc runtime */
117#undef TARGET_HAS_BIONIC
118#define TARGET_HAS_BIONIC (OPTION_BIONIC)
119
120/* musl avoids problematic includes by rearranging the include directories.
121 * Unfortunately, this is mostly duplicated from cppdefault.cc */
122#if DEFAULT_LIBC == LIBC_MUSL
123#define INCLUDE_DEFAULTS_MUSL_GPP \
124 { GPLUSPLUS_INCLUDE_DIR, "G++", 1, 1, \
125 GPLUSPLUS_INCLUDE_DIR_ADD_SYSROOT, 0 }, \
126 { GPLUSPLUS_TOOL_INCLUDE_DIR, "G++", 1, 1, \
127 GPLUSPLUS_INCLUDE_DIR_ADD_SYSROOT, 1 }, \
128 { GPLUSPLUS_BACKWARD_INCLUDE_DIR, "G++", 1, 1, \
129 GPLUSPLUS_INCLUDE_DIR_ADD_SYSROOT, 0 },
130
131#ifdef LOCAL_INCLUDE_DIR
132#define INCLUDE_DEFAULTS_MUSL_LOCAL \
133 { LOCAL_INCLUDE_DIR, 0, 0, 1, 1, 2 }, \
134 { LOCAL_INCLUDE_DIR, 0, 0, 1, 1, 0 },
135#else
136#define INCLUDE_DEFAULTS_MUSL_LOCAL
137#endif
138
139#ifdef PREFIX_INCLUDE_DIR
140#define INCLUDE_DEFAULTS_MUSL_PREFIX \
141 { PREFIX_INCLUDE_DIR, 0, 0, 1, 0, 0},
142#else
143#define INCLUDE_DEFAULTS_MUSL_PREFIX
144#endif
145
146#ifdef CROSS_INCLUDE_DIR
147#define INCLUDE_DEFAULTS_MUSL_CROSS \
148 { CROSS_INCLUDE_DIR, "GCC", 0, 0, 0, 0},
149#else
150#define INCLUDE_DEFAULTS_MUSL_CROSS
151#endif
152
153#ifdef TOOL_INCLUDE_DIR
154#define INCLUDE_DEFAULTS_MUSL_TOOL \
155 { TOOL_INCLUDE_DIR, "BINUTILS", 0, 1, 0, 0},
156#else
157#define INCLUDE_DEFAULTS_MUSL_TOOL
158#endif
159
160#ifdef NATIVE_SYSTEM_HEADER_DIR
161#define INCLUDE_DEFAULTS_MUSL_NATIVE \
162 { NATIVE_SYSTEM_HEADER_DIR, 0, 0, 0, 1, 2 }, \
163 { NATIVE_SYSTEM_HEADER_DIR, 0, 0, 0, 1, 0 },
164#else
165#define INCLUDE_DEFAULTS_MUSL_NATIVE
166#endif
167
168#if defined (CROSS_DIRECTORY_STRUCTURE) && !defined (TARGET_SYSTEM_ROOT)
169# undef INCLUDE_DEFAULTS_MUSL_LOCAL
170# define INCLUDE_DEFAULTS_MUSL_LOCAL
171# undef INCLUDE_DEFAULTS_MUSL_NATIVE
172# define INCLUDE_DEFAULTS_MUSL_NATIVE
173#else
174# undef INCLUDE_DEFAULTS_MUSL_CROSS
175# define INCLUDE_DEFAULTS_MUSL_CROSS
176#endif
177
178#undef INCLUDE_DEFAULTS
179#define INCLUDE_DEFAULTS \
180 { \
181 INCLUDE_DEFAULTS_MUSL_GPP \
182 INCLUDE_DEFAULTS_MUSL_LOCAL \
183 INCLUDE_DEFAULTS_MUSL_PREFIX \
184 INCLUDE_DEFAULTS_MUSL_CROSS \
185 INCLUDE_DEFAULTS_MUSL_TOOL \
186 INCLUDE_DEFAULTS_MUSL_NATIVE \
187 { GCC_INCLUDE_DIR, "GCC", 0, 1, 0, 0 }, \
188 { 0, 0, 0, 0, 0, 0 } \
189 }
190#endif
191
192#if (DEFAULT_LIBC == LIBC_UCLIBC) && defined (SINGLE_LIBC) /* uClinux */
193/* This is a *uclinux* target. We don't define below macros to normal linux
194 versions, because doing so would require *uclinux* targets to include
195 linux.cc, linux-protos.h, linux.opt, etc. We could, alternatively, add
196 these files to *uclinux* targets, but that would only pollute option list
197 (add -mglibc, etc.) without adding any useful support. */
198
199/* Define TARGET_LIBC_HAS_FUNCTION for *uclinux* targets to
200 no_c99_libc_has_function, because uclibc does not, normally, have
201 c99 runtime. If, in special cases, uclibc does have c99 runtime,
202 this should be defined to a new hook. Also please note that for targets
203 like *-linux-uclibc that similar check will also need to be added to
204 linux_libc_has_function. */
205# undef TARGET_LIBC_HAS_FUNCTION
206# define TARGET_LIBC_HAS_FUNCTION no_c99_libc_has_function
207
208#else /* !uClinux, i.e., normal Linux */
209
210/* Determine what functions are present at the runtime;
211 this includes full c99 runtime and sincos. */
212# undef TARGET_LIBC_HAS_FUNCTION
213# define TARGET_LIBC_HAS_FUNCTION linux_libc_has_function
214
215# undef TARGET_LIBM_FUNCTION_MAX_ERROR
216# define TARGET_LIBM_FUNCTION_MAX_ERROR linux_libm_function_max_error
217
218#undef TARGET_FORTIFY_SOURCE_DEFAULT_LEVEL
219#define TARGET_FORTIFY_SOURCE_DEFAULT_LEVEL linux_fortify_source_default_level
220
221#endif
222

source code of gcc/config/linux.h