[SystemZ, AsmParser] Enable the mnemonic spell corrector.

This enables the suggestions of other mnemonics when invalid ones are
specified.

Review: Ulrich Weigand
llvm-svn: 308280

llvm/lib/Target/SystemZ/AsmParser/SystemZAsmParser.cpp

@@ -275,6 +275,10 @@ public:
   SMLoc getEndLoc() const override { return EndLoc; }
   void print(raw_ostream &OS) const override;
 
+  /// getLocRange - Get the range between the first and last token of this
+  /// operand.
+  SMRange getLocRange() const { return SMRange(StartLoc, EndLoc); }
+
   // Used by the TableGen code to add particular types of operand
   // to an instruction.
   void addRegOperands(MCInst &Inst, unsigned N) const {
@@ -1164,6 +1168,8 @@ bool SystemZAsmParser::parseOperand(OperandVector &Operands,
   return false;
 }
 
+std::string SystemZMnemonicSpellCheck(StringRef S, uint64_t FBS);
+
 bool SystemZAsmParser::MatchAndEmitInstruction(SMLoc IDLoc, unsigned &Opcode,
                                                OperandVector &Operands,
                                                MCStreamer &Out,
@@ -1209,8 +1215,13 @@ bool SystemZAsmParser::MatchAndEmitInstruction(SMLoc IDLoc, unsigned &Opcode,
     return Error(ErrorLoc, "invalid operand for instruction");
   }
 
-  case Match_MnemonicFail:
-    return Error(IDLoc, "invalid instruction");
+  case Match_MnemonicFail: {
+    uint64_t FBS = ComputeAvailableFeatures(getSTI().getFeatureBits());
+    std::string Suggestion = SystemZMnemonicSpellCheck(
+      ((SystemZOperand &)*Operands[0]).getToken(), FBS);
+    return Error(IDLoc, "invalid instruction" + Suggestion,
+                 ((SystemZOperand &)*Operands[0]).getLocRange());
+  }
   }
 
   llvm_unreachable("Unexpected match type");

llvm/test/MC/SystemZ/invalid-instructions-spellcheck.s

+# RUN: not llvm-mc -triple=systemz -mcpu=z13 -show-encoding < %s 2>&1 | FileCheck %s
+# RUN: not llvm-mc -triple=systemz -mcpu=zEC12 -show-encoding < %s 2>&1 | FileCheck %s --check-prefix=CHECK-ZEC12
+
+# This tests the mnemonic spell checker.
+
+# First check what happens when an instruction is omitted:
+
+  %r1, %r2, %r3
+
+# CHECK:      error: unexpected token at start of statement
+# CHECK-NEXT: %r1, %r2, %r3
+# CHECK-NEXT:   ^
+
+# We don't want to see a suggestion here; the edit distance is too large to
+# give sensible suggestions:
+
+  aaaaaaaaaaaaaaa %r1, %r2, %r3
+
+# CHECK:      error: invalid instruction
+# CHECK-NEXT: aaaaaaaaaaaaaaa %r1, %r2, %r3
+# CHECK-NEXT: ^
+
+# Check that we get one suggestion: 'cpdt' is 1 edit away, i.e. an deletion.
+
+  cpdtX %r1, 0(4, %r15), 0
+
+#CHECK:      error: invalid instruction, did you mean: cpdt
+#CHECK-NEXT: cpdtX %r1, 0(4, %r15), 0
+#CHECK-NEXT: ^
+
+# Check edit distance 1 and 2
+
+  ltTr %r1, %r2
+
+# CHECK:      error: invalid instruction, did you mean: lr, lt, ltdr, ltdtr, lter, ltgr, ltr, ltxr, ltxtr, tr, trtr?
+# CHECK-NEXT: ltTr %r1, %r2
+# CHECK-NEXT: ^
+
+# Check edit distance 1 and 2, just insertions:
+
+  begin 0, 65292
+
+# CHECK:      error: invalid instruction, did you mean: tbegin, tbeginc?
+# CHECK-NEXT: begin 0, 65292
+# CHECK-NEXT: ^
+
+# Check an instruction that is 2 edits away, and also has a lot of candidates:
+
+  adt %r1, 244(%r15)
+
+# CHECK:      error: invalid instruction, did you mean: a, ad, adb, adr, adtr, adtra, d, lat, mad, qadtr?
+# CHECK-NEXT: adt %r1, 244(%r15)
+# CHECK-NEXT: ^
+
+# Here it is checked that we don't suggest instructions that are not supported.
+# For example, in pre-z13 mode we don't want to see suggestions for vector instructions.
+
+  vlvggp %v1, %r2, %r3
+
+# CHECK-ZEC12: error: invalid instruction
+# CHECK-ZEC12: vlvggp
+# CHECK-ZEC12: ^
+
+# CHECK:      error: invalid instruction, did you mean: vlvg, vlvgg, vlvgp?
+# CHECK-NEXT: vlvggp %v1, %r2, %r3
+# CHECK-NEXT: ^