[mips] Add assembler support for .set msa/nomsa directive.

[tomatabacu]

Summary

These directives are used to toggle whether the assembler accepts MSA-specific instructions or not.

Contains work done by Matheus Almeida.

[dsanders]

LGTM. This is a patch that Matheus wrote but hadn't started upstreaming so we'll credit him too in the commit message.

lib/Target/Mips/AsmParser/MipsAsmParser.cpp

#include "MipsGenAsmMatcher.inc"
   bool parseDirectiveNaN();
   bool parseDirectiveSet();
   bool parseDirectiveOption();
 
   bool parseSetAtDirective();
   bool parseSetNoAtDirective();
   bool parseSetMacroDirective();
   bool parseSetNoMacroDirective();
+  bool parseSetMsaDirective();
+  bool parseSetNoMsaDirective();
   bool parseSetReorderDirective();
   bool parseSetNoReorderDirective();
   bool parseSetNoMips16Directive();
   bool parseSetFpDirective();
 
   bool parseSetAssignment();
 
   bool parseDataDirective(unsigned Size, SMLoc L);
if (Options.isReorder()) {
     reportParseError("`noreorder' must be set before `nomacro'");
     return false;
   }
   Options.setNomacro();
   Parser.Lex(); // Consume the EndOfStatement.
   return false;
 }
 
+bool MipsAsmParser::parseSetMsaDirective() {
+  Parser.Lex();
+
+  // If this is not the end of the statement, report an error.
+  if (getLexer().isNot(AsmToken::EndOfStatement))
+    return reportParseError("unexpected token in statement");
+
+  setFeatureBits(Mips::FeatureMSA, "msa");
+  getTargetStreamer().emitDirectiveSetMsa();
+  return false;
+}
+
+bool MipsAsmParser::parseSetNoMsaDirective() {
+  Parser.Lex();
+
+  // If this is not the end of the statement, report an error.
+  if (getLexer().isNot(AsmToken::EndOfStatement))
+    return reportParseError("unexpected token in statement");
+
+  clearFeatureBits(Mips::FeatureMSA, "msa");
+  getTargetStreamer().emitDirectiveSetNoMsa();
+  return false;
+}
+
 bool MipsAsmParser::parseSetNoMips16Directive() {
   Parser.Lex();
   // If this is not the end of the statement, report an error.
   if (getLexer().isNot(AsmToken::EndOfStatement)) {
     reportParseError("unexpected token in statement");
     return false;
   }
   // For now do nothing.
bool MipsAsmParser::parseDirectiveSet() {
   } else if (Tok.getString() == "mips64") {
     return parseSetFeature(Mips::FeatureMips64);
   } else if (Tok.getString() == "mips64r2") {
     return parseSetFeature(Mips::FeatureMips64r2);
   } else if (Tok.getString() == "mips64r6") {
     return parseSetFeature(Mips::FeatureMips64r6);
   } else if (Tok.getString() == "dsp") {
     return parseSetFeature(Mips::FeatureDSP);
+  } else if (Tok.getString() == "msa") {
+    return parseSetMsaDirective();
+  } else if (Tok.getString() == "nomsa") {
+    return parseSetNoMsaDirective();
   } else {
     // It is just an identifier, look for an assignment.
     parseSetAssignment();
     return false;
   }
 
   return true;
 }

lib/Target/Mips/MCTargetDesc/MipsTargetStreamer.cpp

 void MipsTargetStreamer::emitDirectiveSetMicroMips() {}
 void MipsTargetStreamer::emitDirectiveSetNoMicroMips() {}
 void MipsTargetStreamer::emitDirectiveSetMips16() {}
 void MipsTargetStreamer::emitDirectiveSetNoMips16() {}
 void MipsTargetStreamer::emitDirectiveSetReorder() {}
 void MipsTargetStreamer::emitDirectiveSetNoReorder() {}
 void MipsTargetStreamer::emitDirectiveSetMacro() {}
 void MipsTargetStreamer::emitDirectiveSetNoMacro() {}
+void MipsTargetStreamer::emitDirectiveSetMsa() { setCanHaveModuleDir(false); }
+void MipsTargetStreamer::emitDirectiveSetNoMsa() { setCanHaveModuleDir(false); }
 void MipsTargetStreamer::emitDirectiveSetAt() {}
 void MipsTargetStreamer::emitDirectiveSetNoAt() {}
 void MipsTargetStreamer::emitDirectiveEnd(StringRef Name) {}
 void MipsTargetStreamer::emitDirectiveEnt(const MCSymbol &Symbol) {}
 void MipsTargetStreamer::emitDirectiveAbiCalls() {}
 void MipsTargetStreamer::emitDirectiveNaN2008() {}
 void MipsTargetStreamer::emitDirectiveNaNLegacy() {}
 void MipsTargetStreamer::emitDirectiveOptionPic0() {}
void MipsTargetAsmStreamer::emitDirectiveSetMacro() {
   setCanHaveModuleDir(false);
 }
 
 void MipsTargetAsmStreamer::emitDirectiveSetNoMacro() {
   OS << "\t.set\tnomacro\n";
   setCanHaveModuleDir(false);
 }
 
+void MipsTargetAsmStreamer::emitDirectiveSetMsa() {
+  OS << "\t.set\tmsa\n";
+  MipsTargetStreamer::emitDirectiveSetMsa();
+}
+
+void MipsTargetAsmStreamer::emitDirectiveSetNoMsa() {
+  OS << "\t.set\tnomsa\n";
+  MipsTargetStreamer::emitDirectiveSetNoMsa();
+}
+
 void MipsTargetAsmStreamer::emitDirectiveSetAt() {
   OS << "\t.set\tat\n";
   setCanHaveModuleDir(false);
 }
 
 void MipsTargetAsmStreamer::emitDirectiveSetNoAt() {
   OS << "\t.set\tnoat\n";
   setCanHaveModuleDir(false);

lib/Target/Mips/MipsTargetStreamer.h

public:
   virtual void emitDirectiveSetNoMicroMips();
   virtual void emitDirectiveSetMips16();
   virtual void emitDirectiveSetNoMips16();
 
   virtual void emitDirectiveSetReorder();
   virtual void emitDirectiveSetNoReorder();
   virtual void emitDirectiveSetMacro();
   virtual void emitDirectiveSetNoMacro();
+  virtual void emitDirectiveSetMsa();
+  virtual void emitDirectiveSetNoMsa();
   virtual void emitDirectiveSetAt();
   virtual void emitDirectiveSetNoAt();
   virtual void emitDirectiveEnd(StringRef Name);
 
   virtual void emitDirectiveEnt(const MCSymbol &Symbol);
   virtual void emitDirectiveAbiCalls();
   virtual void emitDirectiveNaN2008();
   virtual void emitDirectiveNaNLegacy();
public:
   void emitDirectiveSetNoMicroMips() override;
   void emitDirectiveSetMips16() override;
   void emitDirectiveSetNoMips16() override;
 
   void emitDirectiveSetReorder() override;
   void emitDirectiveSetNoReorder() override;
   void emitDirectiveSetMacro() override;
   void emitDirectiveSetNoMacro() override;
+  void emitDirectiveSetMsa() override;
+  void emitDirectiveSetNoMsa() override;
   void emitDirectiveSetAt() override;
   void emitDirectiveSetNoAt() override;
   void emitDirectiveEnd(StringRef Name) override;
 
   void emitDirectiveEnt(const MCSymbol &Symbol) override;
   void emitDirectiveAbiCalls() override;
   void emitDirectiveNaN2008() override;
   void emitDirectiveNaNLegacy() override;

test/MC/Mips/msa/set-msa-directive-bad.s

+# RUN: not llvm-mc %s -arch=mips -mcpu=mips32r2 2>%t1
+# RUN: FileCheck %s < %t1
+
+    .set nomsa
+    addvi.b     $w14, $w12, 14 # CHECK: error: instruction requires a CPU feature not currently enabled
+
+    .set msa
+    addvi.h     $w26, $w17, 4 
+    
+    .set nomsa
+    addvi.w     $w19, $w13, 11 # CHECK: error: instruction requires a CPU feature not currently enabled

test/MC/Mips/msa/set-msa-directive.s

+# RUN: llvm-mc %s -arch=mips -mcpu=mips32r2 | FileCheck %s
+
+# CHECK:    .set msa
+# CHECK:    addvi.b     $w14, $w12, 14
+# CHECK:    addvi.h     $w26, $w17, 4
+# CHECK:    addvi.w     $w19, $w13, 11
+# CHECK:    addvi.d     $w16, $w19, 7    
+# CHECK:    subvi.b     $w14, $w12, 14
+# CHECK:    subvi.h     $w26, $w17, 4
+# CHECK:    subvi.w     $w19, $w13, 11
+# CHECK:    subvi.d     $w16, $w19, 7
+
+    .set msa
+    addvi.b     $w14, $w12, 14
+    addvi.h     $w26, $w17, 4
+    addvi.w     $w19, $w13, 11
+    addvi.d     $w16, $w19, 7
+    
+    subvi.b     $w14, $w12, 14
+    subvi.h     $w26, $w17, 4
+    subvi.w     $w19, $w13, 11
+    subvi.d     $w16, $w19, 7