| 1 | //===- GCStrategy.cpp - Garbage Collector Description ---------------------===// |
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| 2 | // |
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| 3 | // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions. |
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| 4 | // See https://llvm.org/LICENSE.txt for license information. |
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| 5 | // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception |
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| 6 | // |
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| 7 | //===----------------------------------------------------------------------===// |
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| 8 | // |
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| 9 | // This file implements the policy object GCStrategy which describes the |
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| 10 | // behavior of a given garbage collector. |
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| 11 | // |
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| 12 | //===----------------------------------------------------------------------===// |
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| 13 | |
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| 14 | #include "llvm/IR/GCStrategy.h" |
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| 15 | #include "llvm/ADT/Twine.h" |
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| 16 | #include "llvm/IR/BuiltinGCs.h" |
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| 17 | |
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| 18 | using namespace llvm; |
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| 19 | |
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| 20 | LLVM_INSTANTIATE_REGISTRY(GCRegistry) |
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| 21 | |
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| 22 | GCStrategy::GCStrategy() = default; |
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| 23 | |
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| 24 | std::unique_ptr<GCStrategy> llvm::getGCStrategy(const StringRef Name) { |
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| 25 | for (auto &S : GCRegistry::entries()) |
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| 26 | if (S.getName() == Name) |
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| 27 | return S.instantiate(); |
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| 28 | |
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| 29 | // We need to link all the builtin GCs when LLVM is used as a static library. |
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| 30 | // The linker will quite happily remove the static constructors that register |
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| 31 | // the builtin GCs if we don't use a function from that object. This function |
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| 32 | // does nothing but we need to make sure it is (or at least could be, even |
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| 33 | // with all optimisations enabled) called *somewhere*, and this is a good |
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| 34 | // place to do that: if the GC strategies are being used then this function |
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| 35 | // obviously can't be removed by the linker, and here it won't affect |
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| 36 | // performance, since there's about to be a fatal error anyway. |
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| 37 | llvm::linkAllBuiltinGCs(); |
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| 38 | |
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| 39 | if (GCRegistry::begin() == GCRegistry::end()) { |
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| 40 | // In normal operation, the registry should not be empty. There should |
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| 41 | // be the builtin GCs if nothing else. The most likely scenario here is |
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| 42 | // that we got here without running the initializers used by the Registry |
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| 43 | // itself and it's registration mechanism. |
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| 44 | const std::string error = |
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| 45 | std::string("unsupported GC: " ) + Name.str() + |
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| 46 | " (did you remember to link and initialize the library?)" ; |
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| 47 | report_fatal_error(reason: Twine(error)); |
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| 48 | } else |
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| 49 | report_fatal_error(reason: Twine(std::string("unsupported GC: " ) + Name.str())); |
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| 50 | } |
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| 51 | |
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