1 files changed, 199 insertions, 0 deletions
diff --git a/contrib/llvm/lib/CodeGen/MIRParser/MILexer.cpp b/contrib/llvm/lib/CodeGen/MIRParser/MILexer.cpp
new file mode 100644
index 0000000..e9b3916
--- /dev/null
+++ b/contrib/llvm/lib/CodeGen/MIRParser/MILexer.cpp
@@ -0,0 +1,199 @@
+//===- MILexer.cpp - Machine instructions lexer implementation ----------===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+//
+// This file implements the lexing of machine instructions.
+//
+//===----------------------------------------------------------------------===//
+
+#include "MILexer.h"
+#include "llvm/ADT/Twine.h"
+#include <cctype>
+
+using namespace llvm;
+
+namespace {
+
+/// This class provides a way to iterate and get characters from the source
+/// string.
+class Cursor {
+  const char *Ptr;
+  const char *End;
+
+public:
+  Cursor(NoneType) : Ptr(nullptr), End(nullptr) {}
+
+  explicit Cursor(StringRef Str) {
+    Ptr = Str.data();
+    End = Ptr + Str.size();
+  }
+
+  bool isEOF() const { return Ptr == End; }
+
+  char peek(int I = 0) const { return End - Ptr <= I ? 0 : Ptr[I]; }
+
+  void advance(unsigned I = 1) { Ptr += I; }
+
+  StringRef remaining() const { return StringRef(Ptr, End - Ptr); }
+
+  StringRef upto(Cursor C) const {
+    assert(C.Ptr >= Ptr && C.Ptr <= End);
+    return StringRef(Ptr, C.Ptr - Ptr);
+  }
+
+  StringRef::iterator location() const { return Ptr; }
+
+  operator bool() const { return Ptr != nullptr; }
+};
+
+} // end anonymous namespace
+
+/// Skip the leading whitespace characters and return the updated cursor.
+static Cursor skipWhitespace(Cursor C) {
+  while (isspace(C.peek()))
+    C.advance();
+  return C;
+}
+
+static bool isIdentifierChar(char C) {
+  return isalpha(C) || isdigit(C) || C == '_' || C == '-' || C == '.';
+}
+
+static Cursor maybeLexIdentifier(Cursor C, MIToken &Token) {
+  if (!isalpha(C.peek()) && C.peek() != '_')
+    return None;
+  auto Range = C;
+  while (isIdentifierChar(C.peek()))
+    C.advance();
+  auto Identifier = Range.upto(C);
+  Token = MIToken(Identifier == "_" ? MIToken::underscore : MIToken::Identifier,
+                  Identifier);
+  return C;
+}
+
+static Cursor maybeLexMachineBasicBlock(
+    Cursor C, MIToken &Token,
+    function_ref<void(StringRef::iterator Loc, const Twine &)> ErrorCallback) {
+  if (!C.remaining().startswith("%bb."))
+    return None;
+  auto Range = C;
+  C.advance(4); // Skip '%bb.'
+  if (!isdigit(C.peek())) {
+    Token = MIToken(MIToken::Error, C.remaining());
+    ErrorCallback(C.location(), "expected a number after '%bb.'");
+    return C;
+  }
+  auto NumberRange = C;
+  while (isdigit(C.peek()))
+    C.advance();
+  StringRef Number = NumberRange.upto(C);
+  unsigned StringOffset = 4 + Number.size(); // Drop '%bb.<id>'
+  if (C.peek() == '.') {
+    C.advance(); // Skip '.'
+    ++StringOffset;
+    while (isIdentifierChar(C.peek()))
+      C.advance();
+  }
+  Token = MIToken(MIToken::MachineBasicBlock, Range.upto(C), APSInt(Number),
+                  StringOffset);
+  return C;
+}
+
+static Cursor maybeLexRegister(Cursor C, MIToken &Token) {
+  if (C.peek() != '%')
+    return None;
+  auto Range = C;
+  C.advance(); // Skip '%'
+  while (isIdentifierChar(C.peek()))
+    C.advance();
+  Token = MIToken(MIToken::NamedRegister, Range.upto(C),
+                  /*StringOffset=*/1); // Drop the '%'
+  return C;
+}
+
+static Cursor maybeLexGlobalValue(Cursor C, MIToken &Token) {
+  if (C.peek() != '@')
+    return None;
+  auto Range = C;
+  C.advance(); // Skip the '@'
+  // TODO: add support for quoted names.
+  if (!isdigit(C.peek())) {
+    while (isIdentifierChar(C.peek()))
+      C.advance();
+    Token = MIToken(MIToken::NamedGlobalValue, Range.upto(C),
+                    /*StringOffset=*/1); // Drop the '@'
+    return C;
+  }
+  auto NumberRange = C;
+  while (isdigit(C.peek()))
+    C.advance();
+  Token =
+      MIToken(MIToken::GlobalValue, Range.upto(C), APSInt(NumberRange.upto(C)));
+  return C;
+}
+
+static Cursor maybeLexIntegerLiteral(Cursor C, MIToken &Token) {
+  if (!isdigit(C.peek()) && (C.peek() != '-' || !isdigit(C.peek(1))))
+    return None;
+  auto Range = C;
+  C.advance();
+  while (isdigit(C.peek()))
+    C.advance();
+  StringRef StrVal = Range.upto(C);
+  Token = MIToken(MIToken::IntegerLiteral, StrVal, APSInt(StrVal));
+  return C;
+}
+
+static MIToken::TokenKind symbolToken(char C) {
+  switch (C) {
+  case ',':
+    return MIToken::comma;
+  case '=':
+    return MIToken::equal;
+  default:
+    return MIToken::Error;
+  }
+}
+
+static Cursor maybeLexSymbol(Cursor C, MIToken &Token) {
+  auto Kind = symbolToken(C.peek());
+  if (Kind == MIToken::Error)
+    return None;
+  auto Range = C;
+  C.advance();
+  Token = MIToken(Kind, Range.upto(C));
+  return C;
+}
+
+StringRef llvm::lexMIToken(
+    StringRef Source, MIToken &Token,
+    function_ref<void(StringRef::iterator Loc, const Twine &)> ErrorCallback) {
+  auto C = skipWhitespace(Cursor(Source));
+  if (C.isEOF()) {
+    Token = MIToken(MIToken::Eof, C.remaining());
+    return C.remaining();
+  }
+
+  if (Cursor R = maybeLexIdentifier(C, Token))
+    return R.remaining();
+  if (Cursor R = maybeLexMachineBasicBlock(C, Token, ErrorCallback))
+    return R.remaining();
+  if (Cursor R = maybeLexRegister(C, Token))
+    return R.remaining();
+  if (Cursor R = maybeLexGlobalValue(C, Token))
+    return R.remaining();
+  if (Cursor R = maybeLexIntegerLiteral(C, Token))
+    return R.remaining();
+  if (Cursor R = maybeLexSymbol(C, Token))
+    return R.remaining();
+
+  Token = MIToken(MIToken::Error, C.remaining());
+  ErrorCallback(C.location(),
+                Twine("unexpected character '") + Twine(C.peek()) + "'");
+  return C.remaining();
+}