[LLVM][inline-asm] Altmacro string escape character '!'

This patch is the fourth patch in a series of reviews for the Altmacro feature. 
This patch introduces a new escape character '!' and it depends on D32701.

according to https://sourceware.org/binutils/docs/as/Altmacro.html:
"single-character string escape
To include any single character literally in a string (even if the character would otherwise have some special meaning), you can prefix the character with !' (an exclamation mark). For example, you can write <4.3 !> 5.4!!>' to get the literal text `4.3 > 5.4!'. "

Differential Revision: https://reviews.llvm.org/D32792

llvm-svn: 302652

1 files changed, 21 insertions, 0 deletions

diff --git a/llvm/lib/MC/MCParser/AsmParser.cpp b/llvm/lib/MC/MCParser/AsmParser.cpp
index 66ba853da2f..d213bf3fa3a 100644
--- a/llvm/lib/MC/MCParser/AsmParser.cpp
+++ b/llvm/lib/MC/MCParser/AsmParser.cpp
@@ -288,6 +288,7 @@ public:
 
 private:
   bool isAltmacroString(SMLoc &StrLoc, SMLoc &EndLoc);
+  void altMacroString(StringRef AltMacroStr, std::string &Res);
   bool parseStatement(ParseStatementInfo &Info,
                       MCAsmParserSemaCallback *SI);
   bool parseCurlyBlockScope(SmallVectorImpl<AsmRewrite>& AsmStrRewrites);
@@ -1209,6 +1210,8 @@ bool AsmParser::isAltmacroString(SMLoc &StrLoc, SMLoc &EndLoc) {
   const char *CharPtr = StrLoc.getPointer();
   while ((*CharPtr != '>') && (*CharPtr != '\n') &&
          (*CharPtr != '\r') && (*CharPtr != '\0')){
+	  if(*CharPtr == '!')
+		  CharPtr++;
     CharPtr++;
   }
   if (*CharPtr == '>') {
@@ -1218,6 +1221,15 @@ bool AsmParser::isAltmacroString(SMLoc &StrLoc, SMLoc &EndLoc) {
   return false;
 }
 
+/// \brief creating a string without the escape characters '!'.
+void AsmParser::altMacroString(StringRef AltMacroStr,std::string &Res) {
+  for (int Pos = 0; Pos < AltMacroStr.size(); Pos++) {
+    if (AltMacroStr[Pos] == '!')
+      Pos++;
+    Res += AltMacroStr[Pos];
+  }
+}
+
 /// \brief Parse an expression and return it.
 ///
 ///  expr ::= expr &&,|| expr               -> lowest.
@@ -2309,6 +2321,15 @@ bool AsmParser::expandMacro(raw_svector_ostream &OS, StringRef Body,
                  (*(Token.getString().begin()) == '%') && Token.is(AsmToken::Integer))
               // Emit an integer value to the buffer.
               OS << Token.getIntVal();
+            // Only Token that was validated as a string and begins with '<'
+            // is considered altMacroString!!!
+            else if ((Lexer.IsaAltMacroMode()) &&
+                     (*(Token.getString().begin()) == '<') &&
+                     Token.is(AsmToken::String)) {
+              std::string Res;
+              altMacroString(Token.getStringContents(), Res);
+              OS << Res;
+            }
             // We expect no quotes around the string's contents when
             // parsing for varargs.
             else if (Token.isNot(AsmToken::String) || VarargParameter)