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MIR Parser: adopt the 'maybeLex...' pattern. NFC.

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This commit refactors the machine instruction lexer so that the lexing
functions use the 'maybeLex...' pattern, where they determine if they
can lex the current token by themselves.

Reviewers: Sean Silva

Differential Revision: http://reviews.llvm.org/D10817


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@241078 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Alex Lorenz
2015-06-30 16:51:29 +00:00
parent 5601e30a77
commit 1991c597a4
1 changed files with 37 additions and 22 deletions
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59
lib/CodeGen/MIRParser/MILexer.cpp
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@ -26,6 +26,8 @@ class Cursor {
const char *End; const char *End;
public: public:
Cursor(NoneType) : Ptr(nullptr), End(nullptr) {}
explicit Cursor(StringRef Str) { explicit Cursor(StringRef Str) {
Ptr = Str.data(); Ptr = Str.data();
End = Ptr + Str.size(); End = Ptr + Str.size();
@ -45,6 +47,8 @@ public:
} }
StringRef::iterator location() const { return Ptr; } StringRef::iterator location() const { return Ptr; }
operator bool() const { return Ptr != nullptr; }
}; };
} // end anonymous namespace } // end anonymous namespace
@ -60,7 +64,9 @@ static bool isIdentifierChar(char C) {
return isalpha(C) || isdigit(C) || C == '_' || C == '-' || C == '.'; return isalpha(C) || isdigit(C) || C == '_' || C == '-' || C == '.';
} }
static Cursor lexIdentifier(Cursor C, MIToken &Token) { static Cursor maybeLexIdentifier(Cursor C, MIToken &Token) {
if (!isalpha(C.peek()) && C.peek() != '_')
return None;
auto Range = C; auto Range = C;
while (isIdentifierChar(C.peek())) while (isIdentifierChar(C.peek()))
C.advance(); C.advance();
@ -70,9 +76,11 @@ static Cursor lexIdentifier(Cursor C, MIToken &Token) {
return C; return C;
} }
static Cursor lexMachineBasicBlock( static Cursor maybeLexMachineBasicBlock(
Cursor C, MIToken &Token, Cursor C, MIToken &Token,
function_ref<void(StringRef::iterator Loc, const Twine &)> ErrorCallback) { function_ref<void(StringRef::iterator Loc, const Twine &)> ErrorCallback) {
if (!C.remaining().startswith("%bb."))
return None;
auto Range = C; auto Range = C;
C.advance(4); // Skip '%bb.' C.advance(4); // Skip '%bb.'
if (!isdigit(C.peek())) { if (!isdigit(C.peek())) {
@ -96,7 +104,9 @@ static Cursor lexMachineBasicBlock(
return C; return C;
} }
static Cursor lexPercent(Cursor C, MIToken &Token) { static Cursor maybeLexRegister(Cursor C, MIToken &Token) {
if (C.peek() != '%')
return None;
auto Range = C; auto Range = C;
C.advance(); // Skip '%' C.advance(); // Skip '%'
while (isIdentifierChar(C.peek())) while (isIdentifierChar(C.peek()))
@ -106,7 +116,9 @@ static Cursor lexPercent(Cursor C, MIToken &Token) {
return C; return C;
} }
static Cursor lexGlobalValue(Cursor C, MIToken &Token) { static Cursor maybeLexGlobalValue(Cursor C, MIToken &Token) {
if (C.peek() != '@')
return None;
auto Range = C; auto Range = C;
C.advance(); // Skip the '@' C.advance(); // Skip the '@'
// TODO: add support for quoted names. // TODO: add support for quoted names.
@ -125,7 +137,9 @@ static Cursor lexGlobalValue(Cursor C, MIToken &Token) {
return C; return C;
} }
static Cursor lexIntegerLiteral(Cursor C, MIToken &Token) { static Cursor maybeLexIntegerLiteral(Cursor C, MIToken &Token) {
if (!isdigit(C.peek()) && (C.peek() != '-' || !isdigit(C.peek(1))))
return None;
auto Range = C; auto Range = C;
C.advance(); C.advance();
while (isdigit(C.peek())) while (isdigit(C.peek()))
@ -146,7 +160,10 @@ static MIToken::TokenKind symbolToken(char C) {
} }
} }
static Cursor lexSymbol(Cursor C, MIToken::TokenKind Kind, MIToken &Token) { static Cursor maybeLexSymbol(Cursor C, MIToken &Token) {
auto Kind = symbolToken(C.peek());
if (Kind == MIToken::Error)
return None;
auto Range = C; auto Range = C;
C.advance(); C.advance();
Token = MIToken(Kind, Range.upto(C)); Token = MIToken(Kind, Range.upto(C));
@ -162,23 +179,21 @@ StringRef llvm::lexMIToken(
return C.remaining(); return C.remaining();
} }
auto Char = C.peek(); if (Cursor R = maybeLexIdentifier(C, Token))
if (isalpha(Char) || Char == '_') return R.remaining();
return lexIdentifier(C, Token).remaining(); if (Cursor R = maybeLexMachineBasicBlock(C, Token, ErrorCallback))
if (Char == '%') { return R.remaining();
if (C.remaining().startswith("%bb.")) if (Cursor R = maybeLexRegister(C, Token))
return lexMachineBasicBlock(C, Token, ErrorCallback).remaining(); return R.remaining();
return lexPercent(C, Token).remaining(); if (Cursor R = maybeLexGlobalValue(C, Token))
} return R.remaining();
if (Char == '@') if (Cursor R = maybeLexIntegerLiteral(C, Token))
return lexGlobalValue(C, Token).remaining(); return R.remaining();
if (isdigit(Char) || (Char == '-' && isdigit(C.peek(1)))) if (Cursor R = maybeLexSymbol(C, Token))
return lexIntegerLiteral(C, Token).remaining(); return R.remaining();
MIToken::TokenKind Kind = symbolToken(Char);
if (Kind != MIToken::Error)
return lexSymbol(C, Kind, Token).remaining();
Token = MIToken(MIToken::Error, C.remaining()); Token = MIToken(MIToken::Error, C.remaining());
ErrorCallback(C.location(), ErrorCallback(C.location(),
Twine("unexpected character '") + Twine(Char) + "'"); Twine("unexpected character '") + Twine(C.peek()) + "'");
return C.remaining(); return C.remaining();
} }