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//===- LLVMIRConversionGen.cpp - MLIR LLVM IR builder generator -----------===//
//
// 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 uses tablegen definitions of the LLVM IR Dialect operations to
// generate the code building the LLVM IR from it.
//
//===----------------------------------------------------------------------===//
#include "mlir/Support/LogicalResult.h"
#include "mlir/TableGen/Attribute.h"
#include "mlir/TableGen/GenInfo.h"
#include "mlir/TableGen/Operator.h"
#include "llvm/ADT/StringExtras.h"
#include "llvm/ADT/Twine.h"
#include "llvm/Support/FormatVariadic.h"
#include "llvm/Support/raw_ostream.h"
#include "llvm/TableGen/Record.h"
#include "llvm/TableGen/TableGenBackend.h"
using namespace llvm;
using namespace mlir;
static bool emitError(const Twine &message) {
llvm::errs() << message << "\n";
return false;
}
namespace {
// Helper structure to return a position of the substring in a string.
struct StringLoc {
size_t pos;
size_t length;
// Take a substring identified by this location in the given string.
StringRef in(StringRef str) const { return str.substr(pos, length); }
// A location is invalid if its position is outside the string.
explicit operator bool() { return pos != std::string::npos; }
};
} // namespace
// Find the next TableGen variable in the given pattern. These variables start
// with a `$` character and can contain alphanumeric characters or underscores.
// Return the position of the variable in the pattern and its length, including
// the `$` character. The escape syntax `$$` is also detected and returned.
static StringLoc findNextVariable(StringRef str) {
size_t startPos = str.find('$');
if (startPos == std::string::npos)
return {startPos, 0};
// If we see "$$", return immediately.
if (startPos != str.size() - 1 && str[startPos + 1] == '$')
return {startPos, 2};
// Otherwise, the symbol spans until the first character that is not
// alphanumeric or '_'.
size_t endPos = str.find_if_not([](char c) { return isAlnum(c) || c == '_'; },
startPos + 1);
if (endPos == std::string::npos)
endPos = str.size();
return {startPos, endPos - startPos};
}
// Check if `name` is the name of the variadic operand of `op`. The variadic
// operand can only appear at the last position in the list of operands.
static bool isVariadicOperandName(const tblgen::Operator &op, StringRef name) {
unsigned numOperands = op.getNumOperands();
if (numOperands == 0)
return false;
const auto &operand = op.getOperand(numOperands - 1);
return operand.isVariableLength() && operand.name == name;
}
// Check if `result` is a known name of a result of `op`.
static bool isResultName(const tblgen::Operator &op, StringRef name) {
for (int i = 0, e = op.getNumResults(); i < e; ++i)
if (op.getResultName(i) == name)
return true;
return false;
}
// Check if `name` is a known name of an attribute of `op`.
static bool isAttributeName(const tblgen::Operator &op, StringRef name) {
return llvm::any_of(
op.getAttributes(),
[name](const tblgen::NamedAttribute &attr) { return attr.name == name; });
}
// Check if `name` is a known name of an operand of `op`.
static bool isOperandName(const tblgen::Operator &op, StringRef name) {
for (int i = 0, e = op.getNumOperands(); i < e; ++i)
if (op.getOperand(i).name == name)
return true;
return false;
}
// Emit to `os` the operator-name driven check and the call to LLVM IRBuilder
// for one definition of an LLVM IR Dialect operation. Return true on success.
static bool emitOneBuilder(const Record &record, raw_ostream &os) {
auto op = tblgen::Operator(record);
if (!record.getValue("llvmBuilder"))
return emitError("no 'llvmBuilder' field for op " + op.getOperationName());
// Return early if there is no builder specified.
auto builderStrRef = record.getValueAsString("llvmBuilder");
if (builderStrRef.empty())
return true;
// Progressively create the builder string by replacing $-variables with
// value lookups. Keep only the not-yet-traversed part of the builder pattern
// to avoid re-traversing the string multiple times.
std::string builder;
llvm::raw_string_ostream bs(builder);
while (auto loc = findNextVariable(builderStrRef)) {
auto name = loc.in(builderStrRef).drop_front();
// First, insert the non-matched part as is.
bs << builderStrRef.substr(0, loc.pos);
// Then, rewrite the name based on its kind.
bool isVariadicOperand = isVariadicOperandName(op, name);
if (isOperandName(op, name)) {
auto result = isVariadicOperand
? formatv("lookupValues(op.{0}())", name)
: formatv("valueMapping.lookup(op.{0}())", name);
bs << result;
} else if (isAttributeName(op, name)) {
bs << formatv("op.{0}()", name);
} else if (isResultName(op, name)) {
bs << formatv("valueMapping[op.{0}()]", name);
} else if (name == "_resultType") {
bs << "convertType(op.getResult().getType().cast<LLVM::LLVMType>())";
} else if (name == "_hasResult") {
bs << "opInst.getNumResults() == 1";
} else if (name == "_location") {
bs << "opInst.getLoc()";
} else if (name == "_numOperands") {
bs << "opInst.getNumOperands()";
} else if (name == "$") {
bs << '$';
} else {
return emitError(name + " is neither an argument nor a result of " +
op.getOperationName());
}
// Finally, only keep the untraversed part of the string.
builderStrRef = builderStrRef.substr(loc.pos + loc.length);
}
// Output the check and the rewritten builder string.
os << "if (auto op = dyn_cast<" << op.getQualCppClassName()
<< ">(opInst)) {\n";
os << bs.str() << builderStrRef << "\n";
os << " return success();\n";
os << "}\n";
return true;
}
// Emit all builders. Returns false on success because of the generator
// registration requirements.
static bool emitBuilders(const RecordKeeper &recordKeeper, raw_ostream &os) {
for (const auto *def : recordKeeper.getAllDerivedDefinitions("LLVM_OpBase")) {
if (!emitOneBuilder(*def, os))
return true;
}
return false;
}
namespace {
// Wrapper class around a Tablegen definition of an LLVM enum attribute case.
class LLVMEnumAttrCase : public tblgen::EnumAttrCase {
public:
using tblgen::EnumAttrCase::EnumAttrCase;
// Constructs a case from a non LLVM-specific enum attribute case.
explicit LLVMEnumAttrCase(const tblgen::EnumAttrCase &other)
: tblgen::EnumAttrCase(&other.getDef()) {}
// Returns the C++ enumerant for the LLVM API.
StringRef getLLVMEnumerant() const {
return def->getValueAsString("llvmEnumerant");
}
};
// Wraper class around a Tablegen definition of an LLVM enum attribute.
class LLVMEnumAttr : public tblgen::EnumAttr {
public:
using tblgen::EnumAttr::EnumAttr;
// Returns the C++ enum name for the LLVM API.
StringRef getLLVMClassName() const {
return def->getValueAsString("llvmClassName");
}
// Returns all associated cases viewed as LLVM-specific enum cases.
std::vector<LLVMEnumAttrCase> getAllCases() const {
std::vector<LLVMEnumAttrCase> cases;
for (auto &c : tblgen::EnumAttr::getAllCases())
cases.push_back(LLVMEnumAttrCase(c));
return cases;
}
};
} // namespace
// Emits conversion function "LLVMClass convertEnumToLLVM(Enum)" and containing
// switch-based logic to convert from the MLIR LLVM dialect enum attribute case
// (Enum) to the corresponding LLVM API enumerant
static void emitOneEnumToConversion(const llvm::Record *record,
raw_ostream &os) {
LLVMEnumAttr enumAttr(record);
StringRef llvmClass = enumAttr.getLLVMClassName();
StringRef cppClassName = enumAttr.getEnumClassName();
StringRef cppNamespace = enumAttr.getCppNamespace();
// Emit the function converting the enum attribute to its LLVM counterpart.
os << formatv("static {0} convert{1}ToLLVM({2}::{1} value) {{\n", llvmClass,
cppClassName, cppNamespace);
os << " switch (value) {\n";
for (const auto &enumerant : enumAttr.getAllCases()) {
StringRef llvmEnumerant = enumerant.getLLVMEnumerant();
StringRef cppEnumerant = enumerant.getSymbol();
os << formatv(" case {0}::{1}::{2}:\n", cppNamespace, cppClassName,
cppEnumerant);
os << formatv(" return {0}::{1};\n", llvmClass, llvmEnumerant);
}
os << " }\n";
os << formatv(" llvm_unreachable(\"unknown {0} type\");\n",
enumAttr.getEnumClassName());
os << "}\n\n";
}
// Emits conversion function "Enum convertEnumFromLLVM(LLVMClass)" and
// containing switch-based logic to convert from the LLVM API enumerant to MLIR
// LLVM dialect enum attribute (Enum).
static void emitOneEnumFromConversion(const llvm::Record *record,
raw_ostream &os) {
LLVMEnumAttr enumAttr(record);
StringRef llvmClass = enumAttr.getLLVMClassName();
StringRef cppClassName = enumAttr.getEnumClassName();
StringRef cppNamespace = enumAttr.getCppNamespace();
// Emit the function converting the enum attribute from its LLVM counterpart.
os << formatv("inline {0}::{1} convert{1}FromLLVM({2} value) {{\n",
cppNamespace, cppClassName, llvmClass);
os << " switch (value) {\n";
for (const auto &enumerant : enumAttr.getAllCases()) {
StringRef llvmEnumerant = enumerant.getLLVMEnumerant();
StringRef cppEnumerant = enumerant.getSymbol();
os << formatv(" case {0}::{1}:\n", llvmClass, llvmEnumerant);
os << formatv(" return {0}::{1}::{2};\n", cppNamespace, cppClassName,
cppEnumerant);
}
os << " }\n";
os << formatv(" llvm_unreachable(\"unknown {0} type\");",
enumAttr.getLLVMClassName());
os << "}\n\n";
}
// Emits conversion functions between MLIR enum attribute case and corresponding
// LLVM API enumerants for all registered LLVM dialect enum attributes.
template <bool ConvertTo>
static bool emitEnumConversionDefs(const RecordKeeper &recordKeeper,
raw_ostream &os) {
for (const auto *def : recordKeeper.getAllDerivedDefinitions("LLVM_EnumAttr"))
if (ConvertTo)
emitOneEnumToConversion(def, os);
else
emitOneEnumFromConversion(def, os);
return false;
}
static mlir::GenRegistration
genLLVMIRConversions("gen-llvmir-conversions",
"Generate LLVM IR conversions", emitBuilders);
static mlir::GenRegistration
genEnumToLLVMConversion("gen-enum-to-llvmir-conversions",
"Generate conversions of EnumAttrs to LLVM IR",
emitEnumConversionDefs</*ConvertTo=*/true>);
static mlir::GenRegistration
genEnumFromLLVMConversion("gen-enum-from-llvmir-conversions",
"Generate conversions of EnumAttrs from LLVM IR",
emitEnumConversionDefs</*ConvertTo=*/false>);