Add support for .ifnes pseudo-op.

[sidneym]

Summary

Most of the other if-form pseudos of this type are implemented but this one was missing. .ifnes is the sibling to .ifeqs.

[mcrosier]

Looks good in general with a few comments.

Also, for future reference, please include full context in your patches. See the following link on how to get a full context in Phabricator:
http://llvm.org/docs/Phabricator.html#requesting-a-review-via-the-web-interface

Chad

lib/MC/MCParser/AsmParser.cpp

438

Update comment to reflect that this parse .ifeqs and .ifnes.

3950

This logic is specific to .ifeqs.

You'll need to conditionalize more of the code, if you'd like to reuse the function.

[mcrosier]

This is not ready to land.

[mcrosier]

Please commit the changes to parseDirectiveIfc in a separate patch. Otherwise, LGTM.

lib/MC/MCParser/AsmParser.cpp

enum DirectiveKind {
     DK_BALIGNL, DK_P2ALIGN, DK_P2ALIGNW, DK_P2ALIGNL, DK_ORG, DK_FILL, DK_ENDR,
     DK_BUNDLE_ALIGN_MODE, DK_BUNDLE_LOCK, DK_BUNDLE_UNLOCK,
     DK_ZERO, DK_EXTERN, DK_GLOBL, DK_GLOBAL,
     DK_LAZY_REFERENCE, DK_NO_DEAD_STRIP, DK_SYMBOL_RESOLVER, DK_PRIVATE_EXTERN,
     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_IFEQ, DK_IFGE, DK_IFGT, DK_IFLE, DK_IFLT, DK_IFNE, DK_IFB,
-    DK_IFNB, DK_IFC, DK_IFEQS, DK_IFNC, DK_IFDEF, DK_IFNDEF, DK_IFNOTDEF,
-    DK_ELSEIF, DK_ELSE, DK_ENDIF,
+    DK_IFNB, DK_IFC, DK_IFEQS, DK_IFNC, DK_IFNES, DK_IFDEF, 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,
     DK_CFI_OFFSET, DK_CFI_REL_OFFSET, DK_CFI_PERSONALITY, DK_CFI_LSDA,
     DK_CFI_REMEMBER_STATE, DK_CFI_RESTORE_STATE, DK_CFI_SAME_VALUE,
     DK_CFI_RESTORE, DK_CFI_ESCAPE, DK_CFI_SIGNAL_FRAME, DK_CFI_UNDEFINED,
     DK_CFI_REGISTER, DK_CFI_WINDOW_SAVE,
     DK_MACROS_ON, DK_MACROS_OFF,
private:
   bool parseDirectiveIncbin(); // ".incbin"
 
   // ".if", ".ifeq", ".ifge", ".ifgt" , ".ifle", ".iflt" or ".ifne"
   bool parseDirectiveIf(SMLoc DirectiveLoc, DirectiveKind DirKind);
   // ".ifb" or ".ifnb", depending on ExpectBlank.
   bool parseDirectiveIfb(SMLoc DirectiveLoc, bool ExpectBlank);
   // ".ifc" or ".ifnc", depending on ExpectEqual.
   bool parseDirectiveIfc(SMLoc DirectiveLoc, bool ExpectEqual);
-  // ".ifeqs"
-  bool parseDirectiveIfeqs(SMLoc DirectiveLoc);
+  // ".ifeqs" or ".ifnes", depending on ExpectEqual.
+  bool parseDirectiveIfeqs(SMLoc DirectiveLoc, bool ExpectEqual);
   // ".ifdef" or ".ifndef", depending on expect_defined
   bool parseDirectiveIfdef(SMLoc DirectiveLoc, bool expect_defined);
   bool parseDirectiveElseIf(SMLoc DirectiveLoc); // ".elseif"
   bool parseDirectiveElse(SMLoc DirectiveLoc); // ".else"
   bool parseDirectiveEndIf(SMLoc DirectiveLoc); // .endif
   bool parseEscapedString(std::string &Data) override;
 
   const MCExpr *applyModifierToExpr(const MCExpr *E,
case DK_IFNE:
     return parseDirectiveIf(IDLoc, DirKind);
   case DK_IFB:
     return parseDirectiveIfb(IDLoc, true);
   case DK_IFNB:
     return parseDirectiveIfb(IDLoc, false);
   case DK_IFC:
     return parseDirectiveIfc(IDLoc, true);
   case DK_IFEQS:
-    return parseDirectiveIfeqs(IDLoc);
+    return parseDirectiveIfeqs(IDLoc, true);
   case DK_IFNC:
     return parseDirectiveIfc(IDLoc, false);
+  case DK_IFNES:
+    return parseDirectiveIfeqs(IDLoc, false);
   case DK_IFDEF:
     return parseDirectiveIfdef(IDLoc, true);
   case DK_IFNDEF:
   case DK_IFNOTDEF:
     return parseDirectiveIfdef(IDLoc, false);
   case DK_ELSEIF:
     return parseDirectiveElseIf(IDLoc);
   case DK_ELSE:
if (TheCondState.Ignore) {
     TheCondState.Ignore = !TheCondState.CondMet;
   }
 
   return false;
 }
 
 /// parseDirectiveIfeqs
 ///   ::= .ifeqs string1, string2
-bool AsmParser::parseDirectiveIfeqs(SMLoc DirectiveLoc) {
+bool AsmParser::parseDirectiveIfeqs(SMLoc DirectiveLoc, bool ExpectEqual) {
   if (Lexer.isNot(AsmToken::String)) {
+    if (ExpectEqual)
       TokError("expected string parameter for '.ifeqs' directive");
+    else
+      TokError("expected string parameter for '.ifnes' directive");
     eatToEndOfStatement();
     return true;
   }
 
   StringRef String1 = getTok().getStringContents();
   Lex();
 
   if (Lexer.isNot(AsmToken::Comma)) {
+    if (ExpectEqual)
       TokError("expected comma after first string for '.ifeqs' directive");
+    else
+      TokError("expected comma after first string for '.ifnes' directive");
     eatToEndOfStatement();
     return true;
   }
 
   Lex();
 
   if (Lexer.isNot(AsmToken::String)) {
+    if (ExpectEqual)
       TokError("expected string parameter for '.ifeqs' directive");
+    else
+      TokError("expected string parameter for '.ifnes' directive");
     eatToEndOfStatement();
     return true;
   }
 
   StringRef String2 = getTok().getStringContents();
   Lex();
 
   TheCondStack.push_back(TheCondState);
   TheCondState.TheCond = AsmCond::IfCond;
-  TheCondState.CondMet = String1 == String2;
+  TheCondState.CondMet = ExpectEqual == (String1 == String2);
   TheCondState.Ignore = !TheCondState.CondMet;
 
   return false;
 }
 
 /// parseDirectiveIfdef
 /// ::= .ifdef symbol
 bool AsmParser::parseDirectiveIfdef(SMLoc DirectiveLoc, bool expect_defined) {
void AsmParser::initializeDirectiveKindMap() {
   DirectiveKindMap[".ifle"] = DK_IFLE;
   DirectiveKindMap[".iflt"] = DK_IFLT;
   DirectiveKindMap[".ifne"] = DK_IFNE;
   DirectiveKindMap[".ifb"] = DK_IFB;
   DirectiveKindMap[".ifnb"] = DK_IFNB;
   DirectiveKindMap[".ifc"] = DK_IFC;
   DirectiveKindMap[".ifeqs"] = DK_IFEQS;
   DirectiveKindMap[".ifnc"] = DK_IFNC;
+  DirectiveKindMap[".ifnes"] = DK_IFNES;
   DirectiveKindMap[".ifdef"] = DK_IFDEF;
   DirectiveKindMap[".ifndef"] = DK_IFNDEF;
   DirectiveKindMap[".ifnotdef"] = DK_IFNOTDEF;
   DirectiveKindMap[".elseif"] = DK_ELSEIF;
   DirectiveKindMap[".else"] = DK_ELSE;
   DirectiveKindMap[".end"] = DK_END;
   DirectiveKindMap[".endif"] = DK_ENDIF;
   DirectiveKindMap[".skip"] = DK_SKIP;

test/MC/AsmParser/ifeqs-diagnostics.s

 .ifeqs "string1",
 
 // CHECK: error: expected string parameter for '.ifeqs' directive
 // CHECK: .ifeqs "string1",
 // CHECK:                  ^
 
 // CHECK-NOT: error: unmatched .ifs or .elses
 
+.ifnes
+
+// CHECK: error: expected string parameter for '.ifnes' directive
+// CHECK: .ifnes
+// CHECK:       ^
+
+.ifnes "string1"
+
+// CHECK: error: expected comma after first string for '.ifnes' directive
+// CHECK: .ifnes "string1"
+// CHECK:                 ^
+
+.ifnes "string1",
+
+// CHECK: error: expected string parameter for '.ifnes' directive
+// CHECK: .ifnes "string1",
+// CHECK:                  ^

test/MC/AsmParser/ifnes.s

+# RUN: llvm-mc -triple i386-unknown-unknown %s | FileCheck %s
+
+# CHECK-NOT: .byte 0
+# CHECK: .byte 1
+.ifnes "foo space", "foo space"
+  .byte 0
+.else
+  .byte 1
+.endif
+
+# CHECK-NOT: .byte 0
+# CHECK: .byte 1
+.ifnes "unequal", "unEqual"
+  .byte 1
+.else
+  .byte 0
+.endif
+
+# CHECK-NOT: .byte 0
+# CHECK: .byte 1
+.ifnes "equal", "equal" ; .byte 0 ; .else ; .byte 1 ; .endif
+