1 // Win32-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.win32;
24
25 version (CRuntime_DigitalMars):
26
27 // debug = PRINTF;
28 debug(PRINTF) import core.stdc.stdio;
29 import rt.minfo;
30 import core.stdc.stdlib : malloc, free;
31
32 struct SectionGroup
33 {
opApplySectionGroup34 static int opApply(scope int delegate(ref SectionGroup) dg)
35 {
36 return dg(_sections);
37 }
38
opApplyReverseSectionGroup39 static int opApplyReverse(scope int delegate(ref SectionGroup) dg)
40 {
41 return dg(_sections);
42 }
43
immutableSectionGroup44 @property immutable(ModuleInfo*)[] modules() const nothrow @nogc
45 {
46 return _moduleGroup.modules;
47 }
48
inoutSectionGroup49 @property ref inout(ModuleGroup) moduleGroup() inout nothrow @nogc
50 {
51 return _moduleGroup;
52 }
53
inoutSectionGroup54 @property inout(void[])[] gcRanges() inout nothrow @nogc
55 {
56 return _gcRanges[];
57 }
58
59 private:
60 ModuleGroup _moduleGroup;
61 void[][] _gcRanges;
62 }
63
64 shared(bool) conservative;
65
initSections()66 void initSections() nothrow @nogc
67 {
68 _sections._moduleGroup = ModuleGroup(getModuleInfos());
69
70 import rt.sections;
71 conservative = !scanDataSegPrecisely();
72
73 if (conservative)
74 {
75 _sections._gcRanges = (cast(void[]*) malloc(2 * (void[]).sizeof))[0..2];
76
77 auto databeg = cast(void*)&_xi_a;
78 auto dataend = cast(void*)_moduleinfo_array.ptr;
79 _sections._gcRanges[0] = databeg[0 .. dataend - databeg];
80
81 // skip module info and CONST segment
82 auto bssbeg = cast(void*)&_edata;
83 auto bssend = cast(void*)&_end;
84 _sections._gcRanges[1] = bssbeg[0 .. bssend - bssbeg];
85 }
86 else
87 {
88 size_t count = &_DPend - &_DPbegin;
89 auto ranges = cast(void[]*) malloc(count * (void[]).sizeof);
90 size_t r = 0;
91 void* prev = null;
92 for (size_t i = 0; i < count; i++)
93 {
94 void* addr = (&_DPbegin)[i];
95 if (prev + (void*).sizeof == addr)
96 ranges[r-1] = ranges[r-1].ptr[0 .. ranges[r-1].length + (void*).sizeof];
97 else
98 ranges[r++] = (cast(void**)addr)[0..1];
99 prev = addr;
100 }
101 _sections._gcRanges = ranges[0..r];
102 }
103 }
104
finiSections()105 void finiSections() nothrow @nogc
106 {
107 free(_sections._gcRanges.ptr);
108 }
109
initTLSRanges()110 void[] initTLSRanges() nothrow @nogc
111 {
112 auto pbeg = cast(void*)&_tlsstart;
113 auto pend = cast(void*)&_tlsend;
114 return pbeg[0 .. pend - pbeg];
115 }
116
finiTLSRanges(void[]rng)117 void finiTLSRanges(void[] rng) nothrow @nogc
118 {
119 }
120
scanTLSRanges(void[]rng,scope void delegate (void * pbeg,void * pend)nothrow dg)121 void scanTLSRanges(void[] rng, scope void delegate(void* pbeg, void* pend) nothrow dg) nothrow
122 {
123 if (conservative)
124 {
125 dg(rng.ptr, rng.ptr + rng.length);
126 }
127 else
128 {
129 for (auto p = &_TPbegin; p < &_TPend; )
130 {
131 uint beg = *p++;
132 uint end = beg + cast(uint)((void*).sizeof);
133 while (p < &_TPend && *p == end)
134 {
135 end += (void*).sizeof;
136 p++;
137 }
138 dg(rng.ptr + beg, rng.ptr + end);
139 }
140 }
141 }
142
143 private:
144
145 __gshared SectionGroup _sections;
146
147 // Windows: this gets initialized by minit.asm
148 extern(C) __gshared immutable(ModuleInfo*)[] _moduleinfo_array;
149 extern(C) void _minit() nothrow @nogc;
150
immutable(ModuleInfo *)151 immutable(ModuleInfo*)[] getModuleInfos() nothrow @nogc
152 out (result)
153 {
154 foreach (m; result)
155 assert(m !is null);
156 }
157 body
158 {
159 // _minit directly alters the global _moduleinfo_array
160 _minit();
161 return _moduleinfo_array;
162 }
163
164 extern(C)
165 {
166 extern __gshared
167 {
168 int _xi_a; // &_xi_a just happens to be start of data segment
169 int _edata; // &_edata is start of BSS segment
170 int _end; // &_end is past end of BSS
171
172 void* _DPbegin; // first entry in the array of pointers addresses
173 void* _DPend; // &_DPend points after last entry of array
174 uint _TPbegin; // first entry in the array of TLS offsets of pointers
175 uint _TPend; // &_DPend points after last entry of array
176 }
177
178 extern
179 {
180 int _tlsstart;
181 int _tlsend;
182 }
183 }
184