1 //===-- assembly.h - compiler-rt assembler support macros -----------------===//
2 //
3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4 // See https://llvm.org/LICENSE.txt for license information.
5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6 //
7 //===----------------------------------------------------------------------===//
8 //
9 // This file defines macros for use in compiler-rt assembler source.
10 // This file is not part of the interface of this library.
11 //
12 //===----------------------------------------------------------------------===//
13 
14 #ifndef COMPILERRT_ASSEMBLY_H
15 #define COMPILERRT_ASSEMBLY_H
16 
17 #if defined(__APPLE__) && defined(__aarch64__)
18 #define SEPARATOR %%
19 #else
20 #define SEPARATOR ;
21 #endif
22 
23 #if defined(__APPLE__)
24 #define HIDDEN(name) .private_extern name
25 #define LOCAL_LABEL(name) L_##name
26 // tell linker it can break up file at label boundaries
27 #define FILE_LEVEL_DIRECTIVE .subsections_via_symbols
28 #define SYMBOL_IS_FUNC(name)
29 #define CONST_SECTION .const
30 
31 #define NO_EXEC_STACK_DIRECTIVE
32 
33 #elif defined(__ELF__)
34 
35 #define HIDDEN(name) .hidden name
36 #define LOCAL_LABEL(name) .L_##name
37 #define FILE_LEVEL_DIRECTIVE
38 #if defined(__arm__) || defined(__aarch64__)
39 #define SYMBOL_IS_FUNC(name) .type name,%function
40 #else
41 #define SYMBOL_IS_FUNC(name) .type name,@function
42 #endif
43 #define CONST_SECTION .section .rodata
44 
45 #if defined(__GNU__) || defined(__FreeBSD__) || defined(__Fuchsia__) ||        \
46     defined(__linux__)
47 #define NO_EXEC_STACK_DIRECTIVE .section .note.GNU-stack,"",%progbits
48 #else
49 #define NO_EXEC_STACK_DIRECTIVE
50 #endif
51 
52 #else // !__APPLE__ && !__ELF__
53 
54 #define HIDDEN(name)
55 #define LOCAL_LABEL(name) .L ## name
56 #define FILE_LEVEL_DIRECTIVE
57 #define SYMBOL_IS_FUNC(name)                                                   \
58   .def name SEPARATOR                                                          \
59     .scl 2 SEPARATOR                                                           \
60     .type 32 SEPARATOR                                                         \
61   .endef
62 #define CONST_SECTION .section .rdata,"rd"
63 
64 #define NO_EXEC_STACK_DIRECTIVE
65 
66 #endif
67 
68 #if defined(__arm__) || defined(__aarch64__)
69 #define FUNC_ALIGN                                                             \
70   .text SEPARATOR                                                              \
71   .balign 16 SEPARATOR
72 #else
73 #define FUNC_ALIGN
74 #endif
75 
76 // BTI and PAC gnu property note
77 #define NT_GNU_PROPERTY_TYPE_0 5
78 #define GNU_PROPERTY_AARCH64_FEATURE_1_AND 0xc0000000
79 #define GNU_PROPERTY_AARCH64_FEATURE_1_BTI 1
80 #define GNU_PROPERTY_AARCH64_FEATURE_1_PAC 2
81 
82 #if defined(__ARM_FEATURE_BTI_DEFAULT)
83 #define BTI_FLAG GNU_PROPERTY_AARCH64_FEATURE_1_BTI
84 #else
85 #define BTI_FLAG 0
86 #endif
87 
88 #if __ARM_FEATURE_PAC_DEFAULT & 3
89 #define PAC_FLAG GNU_PROPERTY_AARCH64_FEATURE_1_PAC
90 #else
91 #define PAC_FLAG 0
92 #endif
93 
94 #define GNU_PROPERTY(type, value)                                              \
95   .pushsection .note.gnu.property, "a" SEPARATOR                               \
96   .p2align 3 SEPARATOR                                                         \
97   .word 4 SEPARATOR                                                            \
98   .word 16 SEPARATOR                                                           \
99   .word NT_GNU_PROPERTY_TYPE_0 SEPARATOR                                       \
100   .asciz "GNU" SEPARATOR                                                       \
101   .word type SEPARATOR                                                         \
102   .word 4 SEPARATOR                                                            \
103   .word value SEPARATOR                                                        \
104   .word 0 SEPARATOR                                                            \
105   .popsection
106 
107 #if BTI_FLAG != 0
108 #define BTI_C hint #34
109 #define BTI_J hint #36
110 #else
111 #define BTI_C
112 #define BTI_J
113 #endif
114 
115 #if (BTI_FLAG | PAC_FLAG) != 0
116 #define GNU_PROPERTY_BTI_PAC                                                   \
117   GNU_PROPERTY(GNU_PROPERTY_AARCH64_FEATURE_1_AND, BTI_FLAG | PAC_FLAG)
118 #else
119 #define GNU_PROPERTY_BTI_PAC
120 #endif
121 
122 #if defined(__clang__) || defined(__GCC_HAVE_DWARF2_CFI_ASM)
123 #define CFI_START .cfi_startproc
124 #define CFI_END .cfi_endproc
125 #else
126 #define CFI_START
127 #define CFI_END
128 #endif
129 
130 #if defined(__arm__)
131 
132 // Determine actual [ARM][THUMB[1][2]] ISA using compiler predefined macros:
133 // - for '-mthumb -march=armv6' compiler defines '__thumb__'
134 // - for '-mthumb -march=armv7' compiler defines '__thumb__' and '__thumb2__'
135 #if defined(__thumb2__) || defined(__thumb__)
136 #define DEFINE_CODE_STATE .thumb SEPARATOR
137 #define DECLARE_FUNC_ENCODING    .thumb_func SEPARATOR
138 #if defined(__thumb2__)
139 #define USE_THUMB_2
140 #define IT(cond)  it cond
141 #define ITT(cond) itt cond
142 #define ITE(cond) ite cond
143 #else
144 #define USE_THUMB_1
145 #define IT(cond)
146 #define ITT(cond)
147 #define ITE(cond)
148 #endif // defined(__thumb__2)
149 #else // !defined(__thumb2__) && !defined(__thumb__)
150 #define DEFINE_CODE_STATE .arm SEPARATOR
151 #define DECLARE_FUNC_ENCODING
152 #define IT(cond)
153 #define ITT(cond)
154 #define ITE(cond)
155 #endif
156 
157 #if defined(USE_THUMB_1) && defined(USE_THUMB_2)
158 #error "USE_THUMB_1 and USE_THUMB_2 can't be defined together."
159 #endif
160 
161 #if defined(__ARM_ARCH_4T__) || __ARM_ARCH >= 5
162 #define ARM_HAS_BX
163 #endif
164 #if !defined(__ARM_FEATURE_CLZ) && !defined(USE_THUMB_1) &&  \
165     (__ARM_ARCH >= 6 || (__ARM_ARCH == 5 && !defined(__ARM_ARCH_5__)))
166 #define __ARM_FEATURE_CLZ
167 #endif
168 
169 #ifdef ARM_HAS_BX
170 #define JMP(r) bx r
171 #define JMPc(r, c) bx##c r
172 #else
173 #define JMP(r) mov pc, r
174 #define JMPc(r, c) mov##c pc, r
175 #endif
176 
177 // pop {pc} can't switch Thumb mode on ARMv4T
178 #if __ARM_ARCH >= 5
179 #define POP_PC() pop {pc}
180 #else
181 #define POP_PC()                                                               \
182   pop {ip};                                                                    \
183   JMP(ip)
184 #endif
185 
186 #if defined(USE_THUMB_2)
187 #define WIDE(op) op.w
188 #else
189 #define WIDE(op) op
190 #endif
191 #else // !defined(__arm)
192 #define DECLARE_FUNC_ENCODING
193 #define DEFINE_CODE_STATE
194 #endif
195 
196 #define GLUE2_(a, b) a##b
197 #define GLUE(a, b) GLUE2_(a, b)
198 #define GLUE2(a, b) GLUE2_(a, b)
199 #define GLUE3_(a, b, c) a##b##c
200 #define GLUE3(a, b, c) GLUE3_(a, b, c)
201 #define GLUE4_(a, b, c, d) a##b##c##d
202 #define GLUE4(a, b, c, d) GLUE4_(a, b, c, d)
203 
204 #define SYMBOL_NAME(name) GLUE(__USER_LABEL_PREFIX__, name)
205 
206 #ifdef VISIBILITY_HIDDEN
207 #define DECLARE_SYMBOL_VISIBILITY(name)                                        \
208   HIDDEN(SYMBOL_NAME(name)) SEPARATOR
209 #define DECLARE_SYMBOL_VISIBILITY_UNMANGLED(name) \
210   HIDDEN(name) SEPARATOR
211 #else
212 #define DECLARE_SYMBOL_VISIBILITY(name)
213 #define DECLARE_SYMBOL_VISIBILITY_UNMANGLED(name)
214 #endif
215 
216 #define DEFINE_COMPILERRT_FUNCTION(name)                                       \
217   DEFINE_CODE_STATE                                                            \
218   FILE_LEVEL_DIRECTIVE SEPARATOR                                               \
219   .globl SYMBOL_NAME(name) SEPARATOR                                           \
220   SYMBOL_IS_FUNC(SYMBOL_NAME(name)) SEPARATOR                                  \
221   DECLARE_SYMBOL_VISIBILITY(name)                                              \
222   DECLARE_FUNC_ENCODING                                                        \
223   SYMBOL_NAME(name):
224 
225 #define DEFINE_COMPILERRT_THUMB_FUNCTION(name)                                 \
226   DEFINE_CODE_STATE                                                            \
227   FILE_LEVEL_DIRECTIVE SEPARATOR                                               \
228   .globl SYMBOL_NAME(name) SEPARATOR                                           \
229   SYMBOL_IS_FUNC(SYMBOL_NAME(name)) SEPARATOR                                  \
230   DECLARE_SYMBOL_VISIBILITY(name) SEPARATOR                                    \
231   .thumb_func SEPARATOR                                                        \
232   SYMBOL_NAME(name):
233 
234 #define DEFINE_COMPILERRT_PRIVATE_FUNCTION(name)                               \
235   DEFINE_CODE_STATE                                                            \
236   FILE_LEVEL_DIRECTIVE SEPARATOR                                               \
237   .globl SYMBOL_NAME(name) SEPARATOR                                           \
238   SYMBOL_IS_FUNC(SYMBOL_NAME(name)) SEPARATOR                                  \
239   HIDDEN(SYMBOL_NAME(name)) SEPARATOR                                          \
240   DECLARE_FUNC_ENCODING                                                        \
241   SYMBOL_NAME(name):
242 
243 #define DEFINE_COMPILERRT_PRIVATE_FUNCTION_UNMANGLED(name)                     \
244   DEFINE_CODE_STATE                                                            \
245   .globl name SEPARATOR                                                        \
246   SYMBOL_IS_FUNC(name) SEPARATOR                                               \
247   HIDDEN(name) SEPARATOR                                                       \
248   DECLARE_FUNC_ENCODING                                                        \
249   name:
250 
251 #define DEFINE_COMPILERRT_OUTLINE_FUNCTION_UNMANGLED(name)                     \
252   DEFINE_CODE_STATE                                                            \
253   FUNC_ALIGN                                                                   \
254   .globl name SEPARATOR                                                        \
255   SYMBOL_IS_FUNC(name) SEPARATOR                                               \
256   DECLARE_SYMBOL_VISIBILITY_UNMANGLED(name) SEPARATOR                          \
257   CFI_START SEPARATOR                                                          \
258   DECLARE_FUNC_ENCODING                                                        \
259   name: SEPARATOR BTI_C
260 
261 #define DEFINE_COMPILERRT_FUNCTION_ALIAS(name, target)                         \
262   .globl SYMBOL_NAME(name) SEPARATOR                                           \
263   SYMBOL_IS_FUNC(SYMBOL_NAME(name)) SEPARATOR                                  \
264   DECLARE_SYMBOL_VISIBILITY(SYMBOL_NAME(name)) SEPARATOR                       \
265   .set SYMBOL_NAME(name), SYMBOL_NAME(target) SEPARATOR
266 
267 #if defined(__ARM_EABI__)
268 #define DEFINE_AEABI_FUNCTION_ALIAS(aeabi_name, name)                          \
269   DEFINE_COMPILERRT_FUNCTION_ALIAS(aeabi_name, name)
270 #else
271 #define DEFINE_AEABI_FUNCTION_ALIAS(aeabi_name, name)
272 #endif
273 
274 #ifdef __ELF__
275 #define END_COMPILERRT_FUNCTION(name)                                          \
276   .size SYMBOL_NAME(name), . - SYMBOL_NAME(name)
277 #define END_COMPILERRT_OUTLINE_FUNCTION(name)                                  \
278   CFI_END SEPARATOR                                                            \
279   .size SYMBOL_NAME(name), . - SYMBOL_NAME(name)
280 #else
281 #define END_COMPILERRT_FUNCTION(name)
282 #define END_COMPILERRT_OUTLINE_FUNCTION(name)                                  \
283   CFI_END
284 #endif
285 
286 #endif // COMPILERRT_ASSEMBLY_H
287