[mips] Add new error message and improve testing for parsing the .module directive.

[tomatabacu]

Summary

We used to silently ignore any empty .module's and we used to give an error saying that we found
an "unexpected token at start of statement" when the value of the option wasn't an identifier (e.g. if it was a number).

We now give an error saying that we "expected .module option identifier" in both of those cases.

I also fixed the other tests in mips-abi-bad.s, which all seemed to be broken.

[dsanders]

LGTM.

I also fixed the other tests in mips-abi-bad.s, which all seemed to be broken.

Well spotted. They had whitespace before the colon.

Do the '# CHECK-NEXT: ^' lines work as expected? I believe FileCheck ignores most whitespace so we might only be checking that '^' appears somewhere on the line. If it turns out that that's the case I'm happy for stricter whitespace checking to be a follow-up patch.

[tomatabacu]

You're right, the whitespace is ignored by FileCheck.
Will fix in a follow-up patch.

lib/Target/Mips/AsmParser/MipsAsmParser.cpp

bool MipsAsmParser::parseDirectiveModule() {
   SMLoc L = Lexer.getLoc();
 
   if (!getTargetStreamer().isModuleDirectiveAllowed()) {
     // TODO : get a better message.
     reportParseError(".module directive must appear before any code");
     return false;
   }
 
-  if (Lexer.is(AsmToken::Identifier)) {
-    StringRef Option = Parser.getTok().getString();
-    Parser.Lex();
+  StringRef Option;
+  if (Parser.parseIdentifier(Option)) {
+    reportParseError("expected .module option identifier");
+    return false;
+  }
 
-    if (Option == "oddspreg") {
-      getTargetStreamer().emitDirectiveModuleOddSPReg(true, isABI_O32());
-      clearFeatureBits(Mips::FeatureNoOddSPReg, "nooddspreg");
 
-      if (getLexer().isNot(AsmToken::EndOfStatement)) {
-        reportParseError("unexpected token, expected end of statement");
-        return false;
-      }
+    // If this is not the end of the statement, report an error.
 
-      return false;
-    } else if (Option == "nooddspreg") {
-      if (!isABI_O32()) {
-        Error(L, "'.module nooddspreg' requires the O32 ABI");
-        return false;
-      }
+    return false; // parseDirectiveModule has finished successfully.
 
-      getTargetStreamer().emitDirectiveModuleOddSPReg(false, isABI_O32());
-      setFeatureBits(Mips::FeatureNoOddSPReg, "nooddspreg");
 
-      if (getLexer().isNot(AsmToken::EndOfStatement)) {
-        reportParseError("unexpected token, expected end of statement");
-        return false;
-      }
+    // If this is not the end of the statement, report an error.
 
-      return false;
-    } else if (Option == "fp") {
-      return parseDirectiveModuleFP();
-    }
-
+    return false; // parseDirectiveModule has finished successfully.
+  } else {
     return Error(L, "'" + Twine(Option) + "' is not a valid .module option.");
   }
-
-  return false;
 }
 
 /// parseDirectiveModuleFP
 ///  ::= =32
 ///  ::= =xx
 ///  ::= =64
 bool MipsAsmParser::parseDirectiveModuleFP() {
   MCAsmParser &Parser = getParser();

test/MC/Mips/mips-abi-bad.s

-# Error checking for malformed abi related directives
 # RUN: not llvm-mc -triple mips-unknown-unknown %s 2>&1 | FileCheck %s
-# CHECK: .text
+
+# Error checking for malformed .module directives (and .set fp=...).
+
     .module fp=3
-# CHECK      : mips-abi-bad.s:4:16: error: unsupported option
-# CHECK-NEXT : .module fp=3
-# CHECK-NEXT :           ^
+# CHECK: :[[@LINE-1]]:17: error: unsupported value, expected 'xx', '32' or '64'
+# CHECK-NEXT: .module fp=3
+# CHECK-NEXT:             ^
 
+# FIXME: Add separate test for .set fp=xx/32/64.
     .set fp=xx,6
-# CHECK      :mips-abi-bad.s:5:15: error: unexpected token in statement
-# CHECK-NEXT :    .set fp=xx,6
-# CHECK-NEXT :              ^
+# CHECK: :[[@LINE-1]]:15: error: unexpected token, expected end of statement
+# CHECK-NEXT: .set fp=xx,6
+# CHECK-NEXT:           ^
 
-# CHECK       :.set mips16
+    .module
+# CHECK: :[[@LINE-1]]:12: error: expected .module option identifier
+# CHECK-NEXT: .module
+# CHECK-NEXT:        ^
+
+    .module 34
+# CHECK: :[[@LINE-1]]:13: error: expected .module option identifier
+# CHECK-NEXT: .module 34
+# CHECK-NEXT:         ^
+
     .set mips16
     .module fp=32
-
-# CHECK      :mips-abi-bad.s:14:13: error: .module directive must come before any code
-# CHECK-NEXT :    .module fp=32
-# CHECK-NEXT :            ^
+# CHECK: :[[@LINE-1]]:13: error: .module directive must appear before any code
+# CHECK-NEXT: .module fp=32
+# CHECK-NEXT:         ^