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//=== LexHLSLRootSignature.cpp - Lex Root Signature -----------------------===//
//
// 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 "clang/Lex/LexHLSLRootSignature.h"
namespace clang {
namespace hlsl {
using TokenKind = RootSignatureToken::Kind;
// Lexer Definitions
static bool isNumberChar(char C) {
return isdigit(C) // integer support
|| C == '.' // float support
|| C == 'e' || C == 'E' || C == '-' || C == '+' // exponent support
|| C == 'f' || C == 'F'; // explicit float support
}
RootSignatureToken RootSignatureLexer::lexToken() {
// Discard any leading whitespace
advanceBuffer(Buffer.take_while(isspace).size());
if (isEndOfBuffer())
return RootSignatureToken(TokenKind::end_of_stream, LocOffset);
// Record where this token is in the text for usage in parser diagnostics
RootSignatureToken Result(LocOffset);
char C = Buffer.front();
// Punctuators
switch (C) {
#define PUNCTUATOR(X, Y) \
case Y: { \
Result.TokKind = TokenKind::pu_##X; \
advanceBuffer(); \
return Result; \
}
#include "clang/Lex/HLSLRootSignatureTokenKinds.def"
default:
break;
}
// Number literal
if (isdigit(C) || C == '.') {
Result.NumSpelling = Buffer.take_while(isNumberChar);
// If all values are digits then we have an int literal
bool IsInteger = Result.NumSpelling.find_if_not(isdigit) == StringRef::npos;
Result.TokKind =
IsInteger ? TokenKind::int_literal : TokenKind::float_literal;
advanceBuffer(Result.NumSpelling.size());
return Result;
}
// All following tokens require at least one additional character
if (Buffer.size() <= 1) {
Result = RootSignatureToken(TokenKind::invalid, LocOffset);
return Result;
}
// Peek at the next character to deteremine token type
char NextC = Buffer[1];
// Registers: [tsub][0-9+]
if ((C == 't' || C == 's' || C == 'u' || C == 'b') && isdigit(NextC)) {
// Convert character to the register type.
switch (C) {
case 'b':
Result.TokKind = TokenKind::bReg;
break;
case 't':
Result.TokKind = TokenKind::tReg;
break;
case 'u':
Result.TokKind = TokenKind::uReg;
break;
case 's':
Result.TokKind = TokenKind::sReg;
break;
default:
llvm_unreachable("Switch for an expected token was not provided");
}
advanceBuffer();
// Lex the integer literal
Result.NumSpelling = Buffer.take_while(isNumberChar);
advanceBuffer(Result.NumSpelling.size());
return Result;
}
// Keywords and Enums:
StringRef TokSpelling =
Buffer.take_while([](char C) { return isalnum(C) || C == '_'; });
// Define a large string switch statement for all the keywords and enums
auto Switch = llvm::StringSwitch<TokenKind>(TokSpelling);
#define KEYWORD(NAME) Switch.CaseLower(#NAME, TokenKind::kw_##NAME);
#define ENUM(NAME, LIT) Switch.CaseLower(LIT, TokenKind::en_##NAME);
#include "clang/Lex/HLSLRootSignatureTokenKinds.def"
// Then attempt to retreive a string from it
Result.TokKind = Switch.Default(TokenKind::invalid);
advanceBuffer(TokSpelling.size());
return Result;
}
RootSignatureToken RootSignatureLexer::consumeToken() {
// If we previously peeked then just return the previous value over
if (NextToken && NextToken->TokKind != TokenKind::end_of_stream) {
RootSignatureToken Result = *NextToken;
NextToken = std::nullopt;
return Result;
}
return lexToken();
}
RootSignatureToken RootSignatureLexer::peekNextToken() {
// Already peeked from the current token
if (NextToken)
return *NextToken;
NextToken = lexToken();
return *NextToken;
}
} // namespace hlsl
} // namespace clang
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