1 // Bionic-specific support for sections.
2 // Copyright (C) 2019-2020 Free Software Foundation, Inc.
3
4 // GCC is free software; you can redistribute it and/or modify it under
5 // the terms of the GNU General Public License as published by the Free
6 // Software Foundation; either version 3, or (at your option) any later
7 // version.
8
9 // GCC is distributed in the hope that it will be useful, but WITHOUT ANY
10 // WARRANTY; without even the implied warranty of MERCHANTABILITY or
11 // FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
12 // for more details.
13
14 // Under Section 7 of GPL version 3, you are granted additional
15 // permissions described in the GCC Runtime Library Exception, version
16 // 3.1, as published by the Free Software Foundation.
17
18 // You should have received a copy of the GNU General Public License and
19 // a copy of the GCC Runtime Library Exception along with this program;
20 // see the files COPYING3 and COPYING.RUNTIME respectively. If not, see
21 // <http://www.gnu.org/licenses/>.
22
23 module gcc.sections.android;
24
25 version (CRuntime_Bionic):
26
27 // debug = PRINTF;
28 debug(PRINTF) import core.stdc.stdio;
29 import core.stdc.stdlib : malloc, free;
30 import rt.deh, rt.minfo;
31 import core.sys.posix.pthread;
32 import core.stdc.stdlib : calloc;
33 import core.stdc.string : memcpy;
34
35 struct SectionGroup
36 {
opApplySectionGroup37 static int opApply(scope int delegate(ref SectionGroup) dg)
38 {
39 return dg(_sections);
40 }
41
opApplyReverseSectionGroup42 static int opApplyReverse(scope int delegate(ref SectionGroup) dg)
43 {
44 return dg(_sections);
45 }
46
immutableSectionGroup47 @property immutable(ModuleInfo*)[] modules() const nothrow @nogc
48 {
49 return _moduleGroup.modules;
50 }
51
inoutSectionGroup52 @property ref inout(ModuleGroup) moduleGroup() inout nothrow @nogc
53 {
54 return _moduleGroup;
55 }
56
immutableSectionGroup57 @property immutable(FuncTable)[] ehTables() const nothrow @nogc
58 {
59 auto pbeg = cast(immutable(FuncTable)*)&__start_deh;
60 auto pend = cast(immutable(FuncTable)*)&__stop_deh;
61 return pbeg[0 .. pend - pbeg];
62 }
63
inoutSectionGroup64 @property inout(void[])[] gcRanges() inout nothrow @nogc
65 {
66 return _gcRanges[];
67 }
68
69 private:
70 ModuleGroup _moduleGroup;
71 void[][1] _gcRanges;
72 }
73
initSections()74 void initSections() nothrow @nogc
75 {
76 pthread_key_create(&_tlsKey, null);
77
78 auto mbeg = cast(immutable ModuleInfo**)&__start_minfo;
79 auto mend = cast(immutable ModuleInfo**)&__stop_minfo;
80 _sections.moduleGroup = ModuleGroup(mbeg[0 .. mend - mbeg]);
81
82 auto pbeg = cast(void*)&_tlsend;
83 auto pend = cast(void*)&__bss_end__;
84 // _tlsend is a 32-bit int and may not be 64-bit void*-aligned, so align pbeg.
85 version (D_LP64) pbeg = cast(void*)(cast(size_t)(pbeg + 7) & ~cast(size_t)7);
86 _sections._gcRanges[0] = pbeg[0 .. pend - pbeg];
87 }
88
finiSections()89 void finiSections() nothrow @nogc
90 {
91 pthread_key_delete(_tlsKey);
92 }
93
initTLSRanges()94 void[]* initTLSRanges() nothrow @nogc
95 {
96 return &getTLSBlock();
97 }
98
finiTLSRanges(void[]* rng)99 void finiTLSRanges(void[]* rng) nothrow @nogc
100 {
101 .free(rng.ptr);
102 .free(rng);
103 }
104
scanTLSRanges(void[]* rng,scope void delegate (void * pbeg,void * pend)nothrow dg)105 void scanTLSRanges(void[]* rng, scope void delegate(void* pbeg, void* pend) nothrow dg) nothrow
106 {
107 dg(rng.ptr, rng.ptr + rng.length);
108 }
109
110 /* NOTE: The Bionic C library ignores thread-local data stored in the normal
111 * .tbss/.tdata ELF sections, which are marked with the SHF_TLS/STT_TLS
112 * flags. So instead we roll our own by keeping TLS data in the
113 * .tdata/.tbss sections but removing the SHF_TLS/STT_TLS flags, and
114 * access the TLS data using this function and the _tlsstart/_tlsend
115 * symbols as delimiters.
116 *
117 * This function is called by the code emitted by the compiler. It
118 * is expected to translate an address in the TLS static data to
119 * the corresponding address in the TLS dynamic per-thread data.
120 */
121
__tls_get_addr(void * p)122 extern(C) void* __tls_get_addr( void* p ) nothrow @nogc
123 {
124 debug(PRINTF) printf(" __tls_get_addr input - %p\n", p);
125 immutable offset = cast(size_t)(p - cast(void*)&_tlsstart);
126 auto tls = getTLSBlockAlloc();
127 assert(offset < tls.length);
128 return tls.ptr + offset;
129 }
130
131 private:
132
133 __gshared pthread_key_t _tlsKey;
134
getTLSBlock()135 ref void[] getTLSBlock() nothrow @nogc
136 {
137 auto pary = cast(void[]*)pthread_getspecific(_tlsKey);
138 if (pary is null)
139 {
140 pary = cast(void[]*).calloc(1, (void[]).sizeof);
141 if (pthread_setspecific(_tlsKey, pary) != 0)
142 {
143 import core.stdc.stdio;
144 perror("pthread_setspecific failed with");
145 assert(0);
146 }
147 }
148 return *pary;
149 }
150
getTLSBlockAlloc()151 ref void[] getTLSBlockAlloc() nothrow @nogc
152 {
153 auto pary = &getTLSBlock();
154 if (!pary.length)
155 {
156 auto pbeg = cast(void*)&_tlsstart;
157 auto pend = cast(void*)&_tlsend;
158 auto p = .malloc(pend - pbeg);
159 memcpy(p, pbeg, pend - pbeg);
160 *pary = p[0 .. pend - pbeg];
161 }
162 return *pary;
163 }
164
165 __gshared SectionGroup _sections;
166
167 extern(C)
168 {
169 /* Symbols created by the compiler/linker and inserted into the
170 * object file that 'bracket' sections.
171 */
172 extern __gshared
173 {
174 void* __start_deh;
175 void* __stop_deh;
176 void* __start_minfo;
177 void* __stop_minfo;
178
179 size_t __bss_end__;
180
181 int _tlsstart;
182 int _tlsend;
183 }
184 }
185