AsmParser: support .ifeqs directive

The .ifeqs directive assembles the following code if the quoted string
parameters are equal.  The strings must be quoted using double quotes.

llvm-svn: 201998

llvm/lib/MC/MCParser/AsmParser.cpp

@@ -350,8 +350,8 @@ private:
     DK_REFERENCE, DK_WEAK_DEFINITION, DK_WEAK_REFERENCE,
     DK_WEAK_DEF_CAN_BE_HIDDEN, DK_COMM, DK_COMMON, DK_LCOMM, DK_ABORT,
     DK_INCLUDE, DK_INCBIN, DK_CODE16, DK_CODE16GCC, DK_REPT, DK_IRP, DK_IRPC,
-    DK_IF, DK_IFNE, DK_IFB, DK_IFNB, DK_IFC, DK_IFNC, DK_IFDEF, DK_IFNDEF,
+    DK_IF, DK_IFNE, DK_IFB, DK_IFNB, DK_IFC, DK_IFEQS, DK_IFNC, DK_IFDEF,
-    DK_IFNOTDEF, DK_ELSEIF, DK_ELSE, DK_ENDIF,
+    DK_IFNDEF, DK_IFNOTDEF, DK_ELSEIF, DK_ELSE, DK_ENDIF,
     DK_SPACE, DK_SKIP, DK_FILE, DK_LINE, DK_LOC, DK_STABS,
     DK_CFI_SECTIONS, DK_CFI_STARTPROC, DK_CFI_ENDPROC, DK_CFI_DEF_CFA,
     DK_CFI_DEF_CFA_OFFSET, DK_CFI_ADJUST_CFA_OFFSET, DK_CFI_DEF_CFA_REGISTER,
@@ -444,6 +444,8 @@ private:
   bool parseDirectiveIfb(SMLoc DirectiveLoc, bool ExpectBlank);
   // ".ifc" or ".ifnc", depending on ExpectEqual.
   bool parseDirectiveIfc(SMLoc DirectiveLoc, bool ExpectEqual);
+  // ".ifeqs"
+  bool parseDirectiveIfeqs(SMLoc DirectiveLoc);
   // ".ifdef" or ".ifndef", depending on expect_defined
   bool parseDirectiveIfdef(SMLoc DirectiveLoc, bool expect_defined);
   bool parseDirectiveElseIf(SMLoc DirectiveLoc); // ".elseif"
@@ -1239,6 +1241,8 @@ bool AsmParser::parseStatement(ParseStatementInfo &Info) {
     return parseDirectiveIfb(IDLoc, false);
   case DK_IFC:
     return parseDirectiveIfc(IDLoc, true);
+  case DK_IFEQS:
+    return parseDirectiveIfeqs(IDLoc);
   case DK_IFNC:
     return parseDirectiveIfc(IDLoc, false);
   case DK_IFDEF:
@@ -3845,6 +3849,43 @@ bool AsmParser::parseDirectiveIfc(SMLoc DirectiveLoc, bool ExpectEqual) {
   return false;
 }
 
+/// parseDirectiveIfeqs
+///   ::= .ifeqs string1, string2
+bool AsmParser::parseDirectiveIfeqs(SMLoc DirectiveLoc) {
+  if (Lexer.isNot(AsmToken::String)) {
+    TokError("expected string parameter for '.ifeqs' directive");
+    eatToEndOfStatement();
+    return true;
+  }
+
+  StringRef String1 = getTok().getStringContents();
+  Lex();
+
+  if (Lexer.isNot(AsmToken::Comma)) {
+    TokError("expected comma after first string for '.ifeqs' directive");
+    eatToEndOfStatement();
+    return true;
+  }
+
+  Lex();
+
+  if (Lexer.isNot(AsmToken::String)) {
+    TokError("expected string parameter for '.ifeqs' directive");
+    eatToEndOfStatement();
+    return true;
+  }
+
+  StringRef String2 = getTok().getStringContents();
+  Lex();
+
+  TheCondStack.push_back(TheCondState);
+  TheCondState.TheCond = AsmCond::IfCond;
+  TheCondState.CondMet = String1 == String2;
+  TheCondState.Ignore = !TheCondState.CondMet;
+
+  return false;
+}
+
 /// parseDirectiveIfdef
 /// ::= .ifdef symbol
 bool AsmParser::parseDirectiveIfdef(SMLoc DirectiveLoc, bool expect_defined) {
@@ -4032,6 +4073,7 @@ void AsmParser::initializeDirectiveKindMap() {
   DirectiveKindMap[".ifb"] = DK_IFB;
   DirectiveKindMap[".ifnb"] = DK_IFNB;
   DirectiveKindMap[".ifc"] = DK_IFC;
+  DirectiveKindMap[".ifeqs"] = DK_IFEQS;
   DirectiveKindMap[".ifnc"] = DK_IFNC;
   DirectiveKindMap[".ifdef"] = DK_IFDEF;
   DirectiveKindMap[".ifndef"] = DK_IFNDEF;

llvm/test/MC/AsmParser/ifeqs.s

@@ -0,0 +1,20 @@
+// RUN: llvm-mc -triple i386 %s | FileCheck %s
+
+.ifeqs "alpha", "alpha"
+	.byte 1
+.else
+	.byte 0
+.endif
+
+// CHECK-NOT: .byte 0
+// CHECK: .byte 1
+
+.ifeqs "alpha", "alpha "
+	.byte 0
+.else
+	.byte 1
+.endif
+
+// CHECK-NOT: .byte 0
+// CHECK: .byte 1
+