llvm/llvm/lib/CodeGen/AsmPrinter/OcamlGCPrinter.cpp

//===- OcamlGCPrinter.cpp - Ocaml frametable emitter ----------------------===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//
//
// This file implements printing the assembly code for an Ocaml frametable.
//
//===----------------------------------------------------------------------===//

#include "llvm/ADT/STLExtras.h"
#include "llvm/ADT/SmallString.h"
#include "llvm/ADT/Twine.h"
#include "llvm/CodeGen/AsmPrinter.h"
#include "llvm/CodeGen/GCMetadata.h"
#include "llvm/CodeGen/GCMetadataPrinter.h"
#include "llvm/IR/BuiltinGCs.h"
#include "llvm/IR/DataLayout.h"
#include "llvm/IR/Function.h"
#include "llvm/IR/Mangler.h"
#include "llvm/IR/Module.h"
#include "llvm/MC/MCContext.h"
#include "llvm/MC/MCDirectives.h"
#include "llvm/MC/MCStreamer.h"
#include "llvm/Support/ErrorHandling.h"
#include "llvm/Target/TargetLoweringObjectFile.h"
#include <cctype>
#include <cstddef>
#include <cstdint>
#include <string>

usingnamespacellvm;

namespace {

class OcamlGCMetadataPrinter : public GCMetadataPrinter { … };

} // end anonymous namespace

static GCMetadataPrinterRegistry::Add<OcamlGCMetadataPrinter>
    Y("ocaml", "ocaml 3.10-compatible collector");

void llvm::linkOcamlGCPrinter() { … }

static void EmitCamlGlobal(const Module &M, AsmPrinter &AP, const char *Id) { … }

void OcamlGCMetadataPrinter::beginAssembly(Module &M, GCModuleInfo &Info,
                                           AsmPrinter &AP) { … }

/// emitAssembly - Print the frametable. The ocaml frametable format is thus:
///
///   extern "C" struct align(sizeof(intptr_t)) {
///     uint16_t NumDescriptors;
///     struct align(sizeof(intptr_t)) {
///       void *ReturnAddress;
///       uint16_t FrameSize;
///       uint16_t NumLiveOffsets;
///       uint16_t LiveOffsets[NumLiveOffsets];
///     } Descriptors[NumDescriptors];
///   } caml${module}__frametable;
///
/// Note that this precludes programs from stack frames larger than 64K
/// (FrameSize and LiveOffsets would overflow). FrameTablePrinter will abort if
/// either condition is detected in a function which uses the GC.
///
void OcamlGCMetadataPrinter::finishAssembly(Module &M, GCModuleInfo &Info,
                                            AsmPrinter &AP) { … }