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//===-- "main" function of libc-wrappergen --------------------------------===//
//
// 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
//
//===----------------------------------------------------------------------===//
#include "utils/LibcTableGenUtil/APIIndexer.h"
#include "llvm/ADT/StringRef.h"
#include "llvm/Support/CommandLine.h"
#include "llvm/Support/Error.h"
#include "llvm/Support/JSON.h"
#include "llvm/Support/MemoryBuffer.h"
#include "llvm/TableGen/Error.h"
#include "llvm/TableGen/Main.h"
#include <fstream>
#include <map>
#include <sstream>
#include <string>
llvm::cl::opt<bool>
GenWrapper("gen-wrapper",
llvm::cl::desc("Generate a C wrapper for <name>."));
llvm::cl::opt<bool> GenAlias("gen-alias",
llvm::cl::desc("Generate a C alias for <name>."));
llvm::cl::opt<std::string>
FunctionName("name", llvm::cl::desc("Name of the function to be wrapped."),
llvm::cl::value_desc("<function name>"), llvm::cl::Required);
llvm::cl::opt<std::string> MangledNameString(
"mangled-name", llvm::cl::desc("Declare as an alias to this mangled name."),
llvm::cl::value_desc("<aliasee string>"));
llvm::cl::opt<std::string> MangledNameFile(
"mangled-name-file",
llvm::cl::desc("Declare as an alias to the C name read from "
"this file."),
llvm::cl::value_desc("<path to a file containing alias name>"));
llvm::cl::opt<std::string>
AppendToFile("append-to-file",
llvm::cl::desc("Append the generated content at the end of "
"the contents of this file."),
llvm::cl::value_desc("<path to a file>"));
void validateOpts() {
int ActionCount = 0;
if (GenWrapper)
++ActionCount;
if (GenAlias)
++ActionCount;
if (ActionCount != 1) {
llvm::PrintFatalError("Exactly one of {--gen-wrapper, --gen-alias} "
"should be specified");
}
if (!MangledNameString.empty() && !MangledNameFile.empty()) {
llvm::PrintFatalError("The options 'mangled-name' and 'mangled-name-file' "
"cannot be specified simultaneously.");
}
}
static std::string getMangledName() {
if (!MangledNameString.empty())
return MangledNameString;
if (MangledNameFile.empty())
llvm::PrintFatalError("At least one of --mangled-name or "
"--mangled-name-file should be specified.");
auto ErrorOrBuf = llvm::MemoryBuffer::getFile(MangledNameFile);
if (!ErrorOrBuf)
llvm::PrintFatalError("Unable to read the mangled name file " +
MangledNameFile);
llvm::StringRef FileContent = ErrorOrBuf.get()->getBuffer().trim();
llvm::SmallVector<llvm::StringRef> Lines;
FileContent.split(Lines, '\n');
for (llvm::StringRef L : Lines) {
if (L.contains("__llvm_libc"))
return std::string(L);
}
llvm::PrintFatalError("Did not find an LLVM libc mangled name in " +
MangledNameFile);
return std::string();
}
void writeAppendToFile(llvm::raw_ostream &OS) {
auto ErrorOrBuf = llvm::MemoryBuffer::getFile(AppendToFile);
if (!ErrorOrBuf) {
llvm::PrintFatalError("Unable to read the file '" + AppendToFile +
"' to append to.");
}
OS << ErrorOrBuf.get()->getBuffer().trim() << '\n';
}
llvm::Record *getFunctionSpec(const llvm_libc::APIIndexer &Indexer) {
auto Iter = Indexer.FunctionSpecMap.find(FunctionName);
if (Iter == Indexer.FunctionSpecMap.end()) {
llvm::PrintFatalError("Function '" + FunctionName +
"' not found in any standard spec.");
}
auto &NameSpecPair = *Iter;
return NameSpecPair.second;
}
std::pair<std::string, bool> writeFunctionHeader(llvm_libc::APIIndexer &Indexer,
llvm::Record *FunctionSpec,
llvm::raw_ostream &OS) {
llvm::Record *RetValSpec = FunctionSpec->getValueAsDef("Return");
llvm::Record *ReturnType = RetValSpec->getValueAsDef("ReturnType");
std::string ReturnTypeString = Indexer.getTypeAsString(ReturnType);
bool ShouldReturn = true;
// We are generating C wrappers in C++ code. So, we should convert the C
// _Noreturn to the C++ [[noreturn]].
llvm::StringRef NR("_Noreturn "); // Note the space after _Noreturn
llvm::StringRef RT(ReturnTypeString);
if (RT.startswith(NR)) {
RT = RT.drop_front(NR.size() - 1); // - 1 because of the space.
ReturnTypeString = std::string("[[noreturn]]") + std::string(RT);
ShouldReturn = false;
}
OS << "extern \"C\" " << ReturnTypeString << " " << FunctionName << "(";
auto ArgsList = FunctionSpec->getValueAsListOfDefs("Args");
std::stringstream CallArgs;
std::string ArgPrefix("__arg");
for (size_t i = 0; i < ArgsList.size(); ++i) {
llvm::Record *ArgType = ArgsList[i]->getValueAsDef("ArgType");
auto TypeName = Indexer.getTypeAsString(ArgType);
if (TypeName.compare("void") == 0) {
if (ArgsList.size() == 1) {
break;
} else {
// the reason this is a fatal error is that a void argument means this
// function has no arguments; multiple copies of no arguments is an
// error.
llvm::PrintFatalError(
"The specification for function " + FunctionName +
" lists other arguments along with a void argument.");
}
}
OS << TypeName << " " << ArgPrefix << i;
CallArgs << ArgPrefix << i;
if (i < ArgsList.size() - 1) {
OS << ", ";
CallArgs << ", ";
}
}
return make_pair(CallArgs.str(), ShouldReturn);
}
static bool generateWrapper(llvm::raw_ostream &OS,
llvm::RecordKeeper &Records) {
llvm_libc::APIIndexer Indexer(Records);
llvm::Record *FunctionSpec = getFunctionSpec(Indexer);
if (AppendToFile.empty()) {
std::string Header = Indexer.FunctionToHeaderMap[FunctionName];
auto RelPath =
llvm::StringRef(Header).drop_back(2); // Drop the ".h" suffix.
OS << "#include \"src/" << RelPath << "/" << FunctionName << ".h\"\n";
} else {
writeAppendToFile(OS);
}
auto Pair = writeFunctionHeader(Indexer, FunctionSpec, OS);
OS << ") {\n"
<< " " << (Pair.second ? "return " : "")
<< "__llvm_libc::" << FunctionName << "(" << Pair.first << ");\n"
<< "}\n";
return false;
}
static bool generateAlias(llvm::raw_ostream &OS, llvm::RecordKeeper &Records) {
if (!AppendToFile.empty())
writeAppendToFile(OS);
llvm_libc::APIIndexer Indexer(Records);
llvm::Record *FunctionSpec = getFunctionSpec(Indexer);
auto Pair = writeFunctionHeader(Indexer, FunctionSpec, OS);
OS << ") __attribute__((alias(\"" << getMangledName() << "\")));\n";
return false;
}
static bool wrapperGenMain(llvm::raw_ostream &OS, llvm::RecordKeeper &Records) {
validateOpts();
if (GenWrapper)
return generateWrapper(OS, Records);
if (GenAlias)
return generateAlias(OS, Records);
__builtin_unreachable();
}
int main(int argc, char *argv[]) {
llvm::cl::ParseCommandLineOptions(argc, argv);
return TableGenMain(argv[0], wrapperGenMain);
}
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