Under emscripten, C code can take the address of a function implemented in Javascript (which is exposed via an import in wasm). Because imports do not have linear memory address in wasm, we need to generate a thunk to be the target of the indirect call; it call the import directly. To make this possible, LLVM needs to emit the type signatures for these functions, because they may not be called directly or referred to other than where the address is taken. This uses s new .s directive (.functype) which specifies the signature. Differential Revision: http://reviews.llvm.org/D20891 Re-apply r271599 but instead of bailing with an error when a declared function has multiple returns, replace it with a pointer argument. Also add the test case I forgot to 'git add' last time around. llvm-svn: 271703
78 lines
2.6 KiB
C++
78 lines
2.6 KiB
C++
//==-- WebAssemblyTargetStreamer.h - WebAssembly Target Streamer -*- C++ -*-==//
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//
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// The LLVM Compiler Infrastructure
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//
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// This file is distributed under the University of Illinois Open Source
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// License. See LICENSE.TXT for details.
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//
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//===----------------------------------------------------------------------===//
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///
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/// \file
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/// \brief This file declares WebAssembly-specific target streamer classes.
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/// These are for implementing support for target-specific assembly directives.
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///
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//===----------------------------------------------------------------------===//
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#ifndef LLVM_LIB_TARGET_WEBASSEMBLY_MCTARGETDESC_WEBASSEMBLYTARGETSTREAMER_H
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#define LLVM_LIB_TARGET_WEBASSEMBLY_MCTARGETDESC_WEBASSEMBLYTARGETSTREAMER_H
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#include "llvm/CodeGen/MachineValueType.h"
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#include "llvm/MC/MCStreamer.h"
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namespace llvm {
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class MCELFStreamer;
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/// WebAssembly-specific streamer interface, to implement support
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/// WebAssembly-specific assembly directives.
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class WebAssemblyTargetStreamer : public MCTargetStreamer {
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public:
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explicit WebAssemblyTargetStreamer(MCStreamer &S);
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/// .param
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virtual void emitParam(ArrayRef<MVT> Types) = 0;
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/// .result
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virtual void emitResult(ArrayRef<MVT> Types) = 0;
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/// .local
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virtual void emitLocal(ArrayRef<MVT> Types) = 0;
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/// .endfunc
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virtual void emitEndFunc() = 0;
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/// .functype
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virtual void emitIndirectFunctionType(StringRef name,
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SmallVectorImpl<MVT> &SignatureVTs,
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size_t NumResults) {
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llvm_unreachable("emitIndirectFunctionType not implemented");
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}
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};
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/// This part is for ascii assembly output
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class WebAssemblyTargetAsmStreamer final : public WebAssemblyTargetStreamer {
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formatted_raw_ostream &OS;
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public:
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WebAssemblyTargetAsmStreamer(MCStreamer &S, formatted_raw_ostream &OS);
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void emitParam(ArrayRef<MVT> Types) override;
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void emitResult(ArrayRef<MVT> Types) override;
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void emitLocal(ArrayRef<MVT> Types) override;
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void emitEndFunc() override;
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void emitIndirectFunctionType(StringRef name,
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SmallVectorImpl<MVT> &SignatureVTs,
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size_t NumResults) override;
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};
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/// This part is for ELF object output
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class WebAssemblyTargetELFStreamer final : public WebAssemblyTargetStreamer {
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public:
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explicit WebAssemblyTargetELFStreamer(MCStreamer &S);
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void emitParam(ArrayRef<MVT> Types) override;
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void emitResult(ArrayRef<MVT> Types) override;
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void emitLocal(ArrayRef<MVT> Types) override;
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void emitEndFunc() override;
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};
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} // end namespace llvm
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#endif
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