[68f9c43] | 1 | // |
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| 2 | // Cforall Version 1.0.0 Copyright (C) 2015 University of Waterloo |
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| 3 | // |
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| 4 | // The contents of this file are covered under the licence agreement in the |
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| 5 | // file "LICENCE" distributed with Cforall. |
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| 6 | // |
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| 7 | // GC.cc -- |
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| 8 | // |
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| 9 | // Author : Aaron B. Moss |
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| 10 | // Created On : Thu Mar 15 14:47:00 2018 |
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| 11 | // Last Modified By : Aaron B. Moss |
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| 12 | // Last Modified On : Thu Mar 15 14:47:00 2018 |
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| 13 | // Update Count : 1 |
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| 14 | // |
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| 15 | |
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| 16 | #include "GC.h" |
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| 17 | |
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[bd06384] | 18 | #include "Common/PassVisitor.h" |
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| 19 | |
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| 20 | #include "SynTree/GcTracer.h" |
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| 21 | |
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[68f9c43] | 22 | #include <algorithm> |
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[7e4b44db] | 23 | #include <cassert> |
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[68f9c43] | 24 | |
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| 25 | GC& GC::get() { |
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| 26 | static GC gc; |
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| 27 | return gc; |
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| 28 | } |
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| 29 | |
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[04570c7] | 30 | GC::GC() : gens(1), static_roots(), mark(false), g(0) { |
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| 31 | gens[0].reserve(70000); |
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[68f9c43] | 32 | } |
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| 33 | |
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| 34 | GC::~GC() { |
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[04570c7] | 35 | for ( unsigned i = 0; i <= g; ++i ) { |
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| 36 | for ( GC_Object* o : gens[i] ) { |
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| 37 | delete o; |
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| 38 | } |
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[68f9c43] | 39 | } |
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| 40 | } |
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| 41 | |
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[24de7b1] | 42 | const GC& GC::operator<< (const GC_Object* obj) const { |
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[68f9c43] | 43 | if( obj ) |
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| 44 | { |
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[f229fc2] | 45 | if( obj->mark != this->mark ) { |
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[68f9c43] | 46 | obj->mark = this->mark; |
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| 47 | obj->trace( *this ); |
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| 48 | } |
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| 49 | } |
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| 50 | return *this; |
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| 51 | } |
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| 52 | |
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[fb97252f] | 53 | // build with flag GC_TRAP to compile in a breakpoint on register and sweep of a dynamically |
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| 54 | // chosen object. Process to use: |
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| 55 | // break GC::register_object |
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| 56 | // run |
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| 57 | // set variable GC_TRAP_OBJ = <target> |
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| 58 | // disable <first breakpoint> |
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[5af7306] | 59 | // continue |
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[fb97252f] | 60 | #ifdef GC_TRAP |
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| 61 | #include <csignal> |
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| 62 | |
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| 63 | /// Set to object to check in debugger |
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| 64 | void* GC_TRAP_OBJ = nullptr; |
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| 65 | #endif |
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| 66 | |
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[68f9c43] | 67 | void GC::register_object(GC_Object* obj) { |
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[fb97252f] | 68 | #ifdef GC_TRAP |
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| 69 | if ( obj == GC_TRAP_OBJ ) std::raise(SIGTRAP); |
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| 70 | #endif |
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[04570c7] | 71 | gens[g].push_back(obj); |
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[f229fc2] | 72 | obj->mark = !this->mark; // initialize as un-marked |
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[68f9c43] | 73 | } |
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| 74 | |
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[bd06384] | 75 | void GC::register_static_root(BaseSyntaxNode* root) { |
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| 76 | static_roots.push_back(root); |
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| 77 | } |
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| 78 | |
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[2efe4b8] | 79 | GC_Guard GC::new_generation() { |
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[04570c7] | 80 | if ( ++g == gens.size() ) { gens.emplace_back(); } // ensure new generation available |
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| 81 | mark = !mark; // switch mark so aged young objects will still be unmarked in old |
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[2efe4b8] | 82 | return { *this, g }; |
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[68f9c43] | 83 | } |
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| 84 | |
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[bd06384] | 85 | void GC::trace_static_roots() { |
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| 86 | PassVisitor<GcTracer> tracer{ *this }; |
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| 87 | for ( BaseSyntaxNode* root : static_roots ) { |
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| 88 | root->accept( tracer ); |
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| 89 | } |
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| 90 | } |
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| 91 | |
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[68f9c43] | 92 | void GC::collect_young() { |
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[04570c7] | 93 | // get generations and decrement generation |
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| 94 | assert(g > 0 && "Cannot collect_young without young generation"); |
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| 95 | Generation& young = gens[g]; |
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| 96 | Generation& old = gens[--g]; |
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| 97 | |
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[7a37f258] | 98 | // ensure static roots traced |
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| 99 | trace_static_roots(); |
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| 100 | |
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[68f9c43] | 101 | // collect young gen |
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| 102 | for ( GC_Object*& obj : young ) { |
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| 103 | if ( obj->mark != mark ) { |
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[fb97252f] | 104 | #ifdef GC_TRAP |
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| 105 | if ( obj == GC_TRAP_OBJ ) std::raise(SIGTRAP); |
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| 106 | #endif |
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[68f9c43] | 107 | delete obj; |
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| 108 | obj = nullptr; |
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| 109 | } |
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| 110 | } |
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| 111 | |
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| 112 | // move uncollected elements into old gen |
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| 113 | auto end_live = std::remove( young.begin(), young.end(), nullptr ); |
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| 114 | old.insert( old.end(), young.begin(), end_live ); |
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| 115 | |
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[04570c7] | 116 | // clear young gen and reset mark to return to old generation mark |
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[68f9c43] | 117 | young.clear(); |
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| 118 | mark = !mark; |
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| 119 | } |
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| 120 | |
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| 121 | void GC::collect() { |
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[f229fc2] | 122 | // ensure not called when young gen is active |
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[04570c7] | 123 | assert(g == 0 && "Cannot do old collection when young generation is active"); |
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| 124 | Generation& old = gens[0]; |
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[f229fc2] | 125 | |
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[7a37f258] | 126 | // ensure static roots traced |
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| 127 | trace_static_roots(); |
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| 128 | |
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[68f9c43] | 129 | // collect old gen |
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| 130 | for ( GC_Object*& obj : old ) { |
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| 131 | if ( obj->mark != mark ) { |
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[fb97252f] | 132 | #ifdef GC_TRAP |
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| 133 | if ( obj == GC_TRAP_OBJ ) std::raise(SIGTRAP); |
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| 134 | #endif |
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[68f9c43] | 135 | delete obj; |
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| 136 | obj = nullptr; |
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| 137 | } |
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| 138 | } |
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| 139 | |
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| 140 | // clear collected elements |
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| 141 | old.erase( std::remove( old.begin(), old.end(), nullptr ), old.end() ); |
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| 142 | |
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[f229fc2] | 143 | // reset mark |
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| 144 | mark = !mark; |
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[68f9c43] | 145 | } |
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| 146 | |
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| 147 | GC_Object::GC_Object() { |
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| 148 | GC::get().register_object( this ); |
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| 149 | } |
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| 150 | |
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[24de7b1] | 151 | GC_Object::GC_Object( const GC_Object& ) { |
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| 152 | GC::get().register_object( this ); |
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| 153 | } |
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| 154 | |
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| 155 | GC_Object::GC_Object( GC_Object&& ) { |
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| 156 | GC::get().register_object( this ); |
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| 157 | } |
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| 158 | |
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[68f9c43] | 159 | // Local Variables: // |
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| 160 | // tab-width: 4 // |
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| 161 | // mode: c++ // |
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| 162 | // compile-command: "make install" // |
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| 163 | // End: // |
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