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7f409cd82b
This change allows a WasmObjectFile to be created from a wasm file even if it uses typed funcrefs and GC types. It does not significantly change how lib/Object models its various internal types (e.g. WasmSignature, WasmElemSegment), so LLVM does not really "support" or understand such files, but it is sufficient to parse the type, global and element sections, discarding types that are not understood. This is useful for low-level binary tools such as nm and objcopy, which use only limited aspects of the binary (such as function definitions) or deal with sections as opaque blobs. This is done by allowing `WasmValType` to have a value of `OTHERREF` (representing any unmodeled reference type), and adding a field to `WasmSignature` indicating it's a placeholder for an unmodeled reference type (since there is a 1:1 correspondence between WasmSignature objects and types in the type section). Then the object file parsers for the type and element sections are expanded to parse encoded reference types and discard any unmodeled fields.
107 lines
2.8 KiB
C++
107 lines
2.8 KiB
C++
//===- InputElement.h ----------------------------------------*- C++ -*-===//
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//
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// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
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// See https://llvm.org/LICENSE.txt for license information.
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// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
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//
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//===----------------------------------------------------------------------===//
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#ifndef LLD_WASM_INPUT_ELEMENT_H
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#define LLD_WASM_INPUT_ELEMENT_H
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#include "Config.h"
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#include "InputFiles.h"
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#include "WriterUtils.h"
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#include "lld/Common/LLVM.h"
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#include "llvm/Object/Wasm.h"
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#include <optional>
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namespace lld {
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namespace wasm {
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// Represents a single element (Global, Tag, Table, etc) within an input
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// file.
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class InputElement {
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protected:
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InputElement(StringRef name, ObjFile *f)
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: file(f), live(!config->gcSections), name(name) {}
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public:
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StringRef getName() const { return name; }
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uint32_t getAssignedIndex() const { return *assignedIndex; }
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bool hasAssignedIndex() const { return assignedIndex.has_value(); }
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void assignIndex(uint32_t index) {
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assert(!hasAssignedIndex());
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assignedIndex = index;
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}
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ObjFile *file;
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bool live = false;
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protected:
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StringRef name;
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std::optional<uint32_t> assignedIndex;
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};
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inline WasmInitExpr intConst(uint64_t value, bool is64) {
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WasmInitExpr ie;
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ie.Extended = false;
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if (is64) {
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ie.Inst.Opcode = llvm::wasm::WASM_OPCODE_I64_CONST;
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ie.Inst.Value.Int64 = static_cast<int64_t>(value);
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} else {
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ie.Inst.Opcode = llvm::wasm::WASM_OPCODE_I32_CONST;
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ie.Inst.Value.Int32 = static_cast<int32_t>(value);
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}
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return ie;
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}
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class InputGlobal : public InputElement {
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public:
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InputGlobal(const WasmGlobal &g, ObjFile *f)
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: InputElement(g.SymbolName, f), type(g.Type), initExpr(g.InitExpr) {}
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const WasmGlobalType &getType() const { return type; }
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const WasmInitExpr &getInitExpr() const { return initExpr; }
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void setPointerValue(uint64_t value) {
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initExpr = intConst(value, config->is64.value_or(false));
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}
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private:
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WasmGlobalType type;
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WasmInitExpr initExpr;
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};
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class InputTag : public InputElement {
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public:
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InputTag(const WasmSignature &s, const WasmTag &t, ObjFile *f)
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: InputElement(t.SymbolName, f), signature(s) {
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assert(s.Kind == WasmSignature::Tag);
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}
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const WasmSignature &signature;
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};
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class InputTable : public InputElement {
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public:
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InputTable(const WasmTable &t, ObjFile *f)
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: InputElement(t.SymbolName, f), type(t.Type) {}
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const WasmTableType &getType() const { return type; }
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void setLimits(const WasmLimits &limits) { type.Limits = limits; }
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private:
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WasmTableType type;
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};
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} // namespace wasm
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inline std::string toString(const wasm::InputElement *d) {
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return (toString(d->file) + ":(" + d->getName() + ")").str();
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}
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} // namespace lld
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#endif // LLD_WASM_INPUT_ELEMENT_H
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