1 // SPDX-License-Identifier: GPL-3.0-or-later
2 /* Definitions of target machine for GNU compiler,
3 for IBM RS/6000 POWER running AIX.
4 Copyright (C) 2000-2023 Free Software Foundation, Inc.
5
6 This file is part of GCC.
7
8 GCC is free software; you can redistribute it and/or modify it
9 under the terms of the GNU General Public License as published
10 by the Free Software Foundation; either version 3, or (at your
11 option) any later version.
12
13 GCC is distributed in the hope that it will be useful, but WITHOUT
14 ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
15 or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public
16 License for more details.
17
18 You should have received a copy of the GNU General Public License
19 along with GCC; see the file COPYING3. If not see
20 <http://www.gnu.org/licenses/>. */
21
22 /* Yes! We are AIX! */
23 #define DEFAULT_ABI ABI_AIX
24 #undef TARGET_AIX
25 #define TARGET_AIX 1
26
27 /* Linux64.h wants to redefine TARGET_AIX based on -m64, but it can't be used
28 in the #if conditional in options-default.h, so provide another macro. */
29 #undef TARGET_AIX_OS
30 #define TARGET_AIX_OS 1
31
32 /* AIX always has a TOC. */
33 #define TARGET_HAS_TOC 1
34 #define FIXED_R2 1
35
36 /* AIX allows r13 to be used in 32-bit mode. */
37 #define FIXED_R13 0
38
39 /* 32-bit and 64-bit AIX stack boundary is 128. */
40 #undef STACK_BOUNDARY
41 #define STACK_BOUNDARY 128
42
43 /* Offset within stack frame to start allocating local variables at.
44 If FRAME_GROWS_DOWNWARD, this is the offset to the END of the
45 first local allocated. Otherwise, it is the offset to the BEGINNING
46 of the first local allocated.
47
48 On the RS/6000, the frame pointer is the same as the stack pointer,
49 except for dynamic allocations. So we start after the fixed area and
50 outgoing parameter area.
51
52 If the function uses dynamic stack space (CALLS_ALLOCA is set), that
53 space needs to be aligned to STACK_BOUNDARY, i.e. the sum of the
54 sizes of the fixed area and the parameter area must be a multiple of
55 STACK_BOUNDARY. */
56
57 #undef RS6000_STARTING_FRAME_OFFSET
58 #define RS6000_STARTING_FRAME_OFFSET \
59 (cfun->calls_alloca \
60 ? RS6000_ALIGN (crtl->outgoing_args_size + RS6000_SAVE_AREA, 16) \
61 : (RS6000_ALIGN (crtl->outgoing_args_size, 16) + RS6000_SAVE_AREA))
62
63 /* Offset from the stack pointer register to an item dynamically
64 allocated on the stack, e.g., by `alloca'.
65
66 The default value for this macro is `STACK_POINTER_OFFSET' plus the
67 length of the outgoing arguments. The default is correct for most
68 machines. See `function.cc' for details.
69
70 This value must be a multiple of STACK_BOUNDARY (hard coded in
71 `emit-rtl.cc'). */
72 #undef STACK_DYNAMIC_OFFSET
73 #define STACK_DYNAMIC_OFFSET(FUNDECL) \
74 RS6000_ALIGN (crtl->outgoing_args_size.to_constant () \
75 + STACK_POINTER_OFFSET, 16)
76
77 #undef TARGET_IEEEQUAD
78 #define TARGET_IEEEQUAD 0
79
80 #undef TARGET_IEEEQUAD_DEFAULT
81 #define TARGET_IEEEQUAD_DEFAULT 0
82
83 /* The AIX linker will discard static constructors in object files before
84 collect has a chance to see them, so scan the object files directly. */
85 #define COLLECT_EXPORT_LIST
86
87 /* On AIX, initialisers specified with -binitfini are called in breadth-first
88 order.
89 e.g. if a.out depends on lib1.so, the init function for a.out is called before
90 the init function for lib1.so.
91
92 To ensure global C++ constructors in linked libraries are run before global
93 C++ constructors from the current module, there is additional symbol scanning
94 logic in collect2.
95
96 The global initialiser/finaliser functions are named __GLOBAL_AIXI_{libname}
97 and __GLOBAL_AIXD_{libname} and are exported from each shared library.
98
99 collect2 will detect these symbols when they exist in shared libraries that
100 the current program is being linked against. All such initiliser functions
101 will be called prior to the constructors of the current program, and
102 finaliser functions called after destructors.
103
104 Reference counting generated by collect2 will ensure that constructors are
105 only invoked once in the case of multiple dependencies on a library.
106
107 -binitfini is still used in parallel to this solution.
108 This handles the case where a library is loaded through dlopen(), and also
109 handles the option -blazy.
110 */
111 #define COLLECT_SHARED_INIT_FUNC(STREAM, FUNC) \
112 fprintf ((STREAM), "void %s() {\n\t%s();\n}\n", aix_shared_initname, (FUNC))
113 #define COLLECT_SHARED_FINI_FUNC(STREAM, FUNC) \
114 fprintf ((STREAM), "void %s() {\n\t%s();\n}\n", aix_shared_fininame, (FUNC))
115
116 #if HAVE_AS_REF
117 /* Issue assembly directives that create a reference to the given DWARF table
118 identifier label from the current function section. This is defined to
119 ensure we drag frame tables associated with needed function bodies in
120 a link with garbage collection activated. */
121 #define ASM_OUTPUT_DWARF_TABLE_REF rs6000_aix_asm_output_dwarf_table_ref
122 #endif
123
124 /* This is the only version of nm that collect2 can work with. */
125 #define REAL_NM_FILE_NAME "/usr/ucb/nm"
126
127 #define USER_LABEL_PREFIX ""
128
129 /* Don't turn -B into -L if the argument specifies a relative file name. */
130 #define RELATIVE_PREFIX_NOT_LINKDIR
131
132 /* Because of the above, we must have gcc search itself to find libgcc.a. */
133 #define LINK_LIBGCC_SPECIAL_1
134
135 /* Names to predefine in the preprocessor for this target machine. */
136 #define TARGET_OS_AIX_CPP_BUILTINS() \
137 do \
138 { \
139 builtin_define ("_IBMR2"); \
140 builtin_define ("_POWER"); \
141 builtin_define ("__unix__"); \
142 builtin_define ("_AIX"); \
143 builtin_define ("_AIX32"); \
144 builtin_define ("_AIX41"); \
145 builtin_define ("_LONG_LONG"); \
146 if (TARGET_LONG_DOUBLE_128) \
147 builtin_define ("__LONGDOUBLE128"); \
148 builtin_assert ("system=unix"); \
149 builtin_assert ("system=aix"); \
150 if (TARGET_64BIT) \
151 { \
152 builtin_define ("__PPC__"); \
153 builtin_define ("__PPC64__"); \
154 builtin_define ("__powerpc__"); \
155 builtin_define ("__powerpc64__"); \
156 builtin_assert ("cpu=powerpc64"); \
157 builtin_assert ("machine=powerpc64"); \
158 } \
159 else \
160 { \
161 builtin_define ("__PPC__"); \
162 builtin_define ("__powerpc__"); \
163 builtin_assert ("cpu=powerpc"); \
164 builtin_assert ("machine=powerpc"); \
165 } \
166 } \
167 while (0)
168
169 /* Define appropriate architecture macros for preprocessor depending on
170 target switches. */
171
172 #define CPP_SPEC "%{posix: -D_POSIX_SOURCE}\
173 %{ansi: -D_ANSI_C_SOURCE}"
174
175 #define CC1_SPEC "%(cc1_cpu)"
176
177 #undef ASM_DEFAULT_SPEC
178 #define ASM_DEFAULT_SPEC ""
179
180 /* Tell the assembler to assume that all undefined names are external.
181
182 Don't do this until the fixed IBM assembler is more generally available.
183 When this becomes permanently defined, the ASM_OUTPUT_EXTERNAL,
184 ASM_OUTPUT_EXTERNAL_LIBCALL, and RS6000_OUTPUT_BASENAME macros will no
185 longer be needed. Also, the extern declaration of mcount in
186 rs6000_xcoff_file_start will no longer be needed. */
187
188 /* #define ASM_SPEC "-u %(asm_cpu)" */
189
190 /* Default location of syscalls.exp under AIX */
191 #define LINK_SYSCALLS_SPEC "-bI:%R/lib/syscalls.exp"
192
193 /* Default location of libg.exp under AIX */
194 #define LINK_LIBG_SPEC "-bexport:%R/usr/lib/libg.exp"
195
196 /* Define the options for the binder: Start text at 512, align all segments
197 to 512 bytes, and warn if there is text relocation.
198
199 The -bhalt:4 option supposedly changes the level at which ld will abort,
200 but it also suppresses warnings about multiply defined symbols and is
201 used by the AIX cc command. So we use it here.
202
203 -bnodelcsect undoes a poor choice of default relating to multiply-defined
204 csects. See AIX documentation for more information about this.
205
206 -bM:SRE tells the linker that the output file is Shared REusable. Note
207 that to actually build a shared library you will also need to specify an
208 export list with the -Wl,-bE option. */
209
210 #define LINK_SPEC "-T512 -H512 %{!r:-btextro} -bhalt:4 -bnodelcsect\
211 %{static:-bnso %(link_syscalls) } \
212 %{!shared:%{g*: %(link_libg) }} %{shared:-bM:SRE}"
213
214 /* Profiled library versions are used by linking with special directories. */
215 #define LIB_SPEC "%{pg:-L%R/lib/profiled -L%R/usr/lib/profiled}\
216 %{p:-L%R/lib/profiled -L%R/usr/lib/profiled} %{!shared:%{g*:-lg}} -lc"
217
218 /* Static linking with shared libstdc++ requires libsupc++ as well. */
219 #define LIBSTDCXX_STATIC "supc++"
220
221 /* This now supports a natural alignment mode. */
222 /* AIX word-aligns FP doubles but doubleword-aligns 64-bit ints. */
223 #define ADJUST_FIELD_ALIGN(FIELD, TYPE, COMPUTED) \
224 (TARGET_ALIGN_NATURAL == 0 \
225 ? rs6000_special_adjust_field_align (TYPE, COMPUTED) \
226 : (COMPUTED))
227
228 /* AIX increases natural record alignment to doubleword if the first
229 field is an FP double while the FP fields remain word aligned. */
230 #define ROUND_TYPE_ALIGN(STRUCT, COMPUTED, SPECIFIED) \
231 ((TREE_CODE (STRUCT) == RECORD_TYPE \
232 || TREE_CODE (STRUCT) == UNION_TYPE \
233 || TREE_CODE (STRUCT) == QUAL_UNION_TYPE) \
234 && TARGET_ALIGN_NATURAL == 0 \
235 ? rs6000_special_round_type_align (STRUCT, COMPUTED, SPECIFIED) \
236 : MAX ((COMPUTED), (SPECIFIED)))
237
238 /* The AIX ABI isn't explicit on whether aggregates smaller than a
239 word/doubleword should be padded upward or downward. One could
240 reasonably assume that they follow the normal rules for structure
241 layout treating the parameter area as any other block of memory,
242 then map the reg param area to registers, i.e., pad upward, which
243 is the way IBM Compilers for AIX behave.
244 Setting both of the following defines results in this behavior. */
245 #define AGGREGATE_PADDING_FIXED 1
246 #define AGGREGATES_PAD_UPWARD_ALWAYS 1
247
248 /* Specify padding for the last element of a block move between
249 registers and memory. FIRST is nonzero if this is the only
250 element. */
251 #define BLOCK_REG_PADDING(MODE, TYPE, FIRST) \
252 (!(FIRST) ? PAD_UPWARD : targetm.calls.function_arg_padding (MODE, TYPE))
253
254 /* Indicate that jump tables go in the text section. */
255
256 #define JUMP_TABLES_IN_TEXT_SECTION 1
257
258 /* Define any extra SPECS that the compiler needs to generate. */
259 #undef SUBTARGET_EXTRA_SPECS
260 #define SUBTARGET_EXTRA_SPECS \
261 { "link_syscalls", LINK_SYSCALLS_SPEC }, \
262 { "link_libg", LINK_LIBG_SPEC }
263
264 #define PROFILE_HOOK(LABEL) output_profile_hook (LABEL)
265
266 /* No version of AIX fully supports AltiVec or 64-bit instructions in
267 32-bit mode. */
268 #define OS_MISSING_POWERPC64 1
269 #define OS_MISSING_ALTIVEC 1
270
271 /* WINT_TYPE */
272 #define WINT_TYPE "int"
273
274 /* Static stack checking is supported by means of probes. */
275 #define STACK_CHECK_STATIC_BUILTIN 1
276
277 /* Use standard DWARF numbering for DWARF debugging information. */
278 #define RS6000_USE_DWARF_NUMBERING
279
280 #define TARGET_PRECOMPUTE_TLS_P rs6000_aix_precompute_tls_p
281
282 /* Replace -m64 with -maix64 and -m32 with -maix32. */
283 #undef SUBTARGET_DRIVER_SELF_SPECS
284 #define SUBTARGET_DRIVER_SELF_SPECS \
285 "%{m64:-maix64} %<m64", \
286 "%{m32:-maix32} %<m32"