[PowerPC] Support ".machine any"

The PowerPC assembler is supposed to provide a directive .machine
that allows switching the supported CPU instruction set on the fly.
Since we do not yet check CPU feature sets at all and always accept
any available instruction, this is not really useful at this point.

However, it makes sense to accept (and ignore) ".machine any" to
avoid spuriously rejecting existing assembler files that use this.

llvm-svn: 185924

llvm/lib/Target/PowerPC/AsmParser/PPCAsmParser.cpp

@@ -196,6 +196,7 @@ class PPCAsmParser : public MCTargetAsmParser {
 
   bool ParseDirectiveWord(unsigned Size, SMLoc L);
   bool ParseDirectiveTC(unsigned Size, SMLoc L);
+  bool ParseDirectiveMachine(SMLoc L);
 
   bool MatchAndEmitInstruction(SMLoc IDLoc, unsigned &Opcode,
                                SmallVectorImpl<MCParsedAsmOperand*> &Operands,
@@ -1182,6 +1183,8 @@ bool PPCAsmParser::ParseDirective(AsmToken DirectiveID) {
     return ParseDirectiveWord(8, DirectiveID.getLoc());
   if (IDVal == ".tc")
     return ParseDirectiveTC(isPPC64()? 8 : 4, DirectiveID.getLoc());
+  if (IDVal == ".machine")
+    return ParseDirectiveMachine(DirectiveID.getLoc());
   return true;
 }
 
@@ -1227,6 +1230,30 @@ bool PPCAsmParser::ParseDirectiveTC(unsigned Size, SMLoc L) {
   return ParseDirectiveWord(Size, L);
 }
 
+/// ParseDirectiveMachine
+///  ::= .machine [ cpu | "push" | "pop" ]
+bool PPCAsmParser::ParseDirectiveMachine(SMLoc L) {
+  if (getLexer().isNot(AsmToken::Identifier) &&
+      getLexer().isNot(AsmToken::String))
+    return Error(L, "unexpected token in directive");
+
+  StringRef CPU = Parser.getTok().getIdentifier();
+  Parser.Lex();
+
+  // FIXME: Right now, the parser always allows any available
+  // instruction, so the .machine directive is not useful.
+  // Implement ".machine any" (by doing nothing) for the benefit
+  // of existing assembler code.  Likewise, we can then implement
+  // ".machine push" and ".machine pop" as no-op.
+  if (CPU != "any" && CPU != "push" && CPU != "pop")
+    return Error(L, "unrecognized machine type");
+
+  if (getLexer().isNot(AsmToken::EndOfStatement))
+    return Error(L, "unexpected token in directive");
+
+  return false;
+}
+
 /// Force static initialization.
 extern "C" void LLVMInitializePowerPCAsmParser() {
   RegisterMCAsmParser<PPCAsmParser> A(ThePPC32Target);

llvm/test/MC/PowerPC/ppc-machine.s

@@ -0,0 +1,14 @@
+# RUN: llvm-mc -triple powerpc-unknown-unknown %s
+# RUN: llvm-mc -triple powerpc64-unknown-unknown %s
+
+# For now, the only thing we check is that the .machine directive
+# is accepted without syntax error.
+
+	.machine push
+	.machine any
+	.machine pop
+
+	.machine "push"
+	.machine "any"
+	.machine "pop"
+