[SPARC][IAS] Rework ASI/Prefetch tag matching in prep for `ParseForAllFeatures`

Unify parts of ASI and Prefetch tag matching at `parseASITag`
and `parsePrefetchTag` to use a common function to parse any immediate
expressions. This introduces a slight regression to error messages,
but is needed so we can enable `ParseForAllFeatures`
in `MatchOperandParserImpl` in a future patch.

Reviewers: jrtc27, brad0, rorth, s-barannikov

Reviewed By: s-barannikov

Pull Request: https://github.com/llvm/llvm-project/pull/96020

3 files changed, 83 insertions, 51 deletions

diff --git a/llvm/lib/Target/Sparc/AsmParser/SparcAsmParser.cpp b/llvm/lib/Target/Sparc/AsmParser/SparcAsmParser.cpp
index f0a3a4e..af634a7 100644
--- a/llvm/lib/Target/Sparc/AsmParser/SparcAsmParser.cpp
+++ b/llvm/lib/Target/Sparc/AsmParser/SparcAsmParser.cpp
@@ -107,10 +107,15 @@ class SparcAsmParser : public MCTargetAsmParser {
 
   ParseStatus parseBranchModifiers(OperandVector &Operands);
 
+  ParseStatus parseExpression(int64_t &Val);
+
   // Helper function for dealing with %lo / %hi in PIC mode.
   const SparcMCExpr *adjustPICRelocation(SparcMCExpr::VariantKind VK,
                                          const MCExpr *subExpr);
 
+  // Helper function to see if current token can start an expression.
+  bool isPossibleExpression(const AsmToken &Token);
+
   // returns true if Tok is matched to a register and returns register in RegNo.
   MCRegister matchRegisterName(const AsmToken &Tok, unsigned &RegKind);
 
@@ -1085,32 +1090,35 @@ ParseStatus SparcAsmParser::parseASITag(OperandVector &Operands) {
   SMLoc E = Parser.getTok().getEndLoc();
   int64_t ASIVal = 0;
 
-  if (is64Bit() && (getLexer().getKind() == AsmToken::Hash)) {
-    // For now we only support named tags for 64-bit/V9 systems.
-    // TODO: add support for 32-bit/V8 systems.
-    SMLoc TagStart = getLexer().peekTok(false).getLoc();
-    Parser.Lex(); // Eat the '#'.
-    auto ASIName = Parser.getTok().getString();
-    auto ASITag = SparcASITag::lookupASITagByName(ASIName);
-    if (!ASITag)
-      ASITag = SparcASITag::lookupASITagByAltName(ASIName);
-    Parser.Lex(); // Eat the identifier token.
+  if (getLexer().getKind() != AsmToken::Hash) {
+    // If the ASI tag provided is not a named tag, then it
+    // must be a constant expression.
+    ParseStatus ParseExprStatus = parseExpression(ASIVal);
+    if (!ParseExprStatus.isSuccess())
+      return ParseExprStatus;
 
-    if (!ASITag)
-      return Error(TagStart, "unknown ASI tag");
-
-    ASIVal = ASITag->Encoding;
-  } else if (!getParser().parseAbsoluteExpression(ASIVal)) {
     if (!isUInt<8>(ASIVal))
       return Error(S, "invalid ASI number, must be between 0 and 255");
-  } else {
-    return Error(
-        S, is64Bit()
-               ? "malformed ASI tag, must be %asi, a constant integer "
-                 "expression, or a named tag"
-               : "malformed ASI tag, must be a constant integer expression");
+
+    Operands.push_back(SparcOperand::CreateASITag(ASIVal, S, E));
+    return ParseStatus::Success;
   }
 
+  // For now we only support named tags for 64-bit/V9 systems.
+  // TODO: add support for 32-bit/V8 systems.
+  SMLoc TagStart = getLexer().peekTok(false).getLoc();
+  Parser.Lex(); // Eat the '#'.
+  const StringRef ASIName = Parser.getTok().getString();
+  const SparcASITag::ASITag *ASITag = SparcASITag::lookupASITagByName(ASIName);
+  if (!ASITag)
+    ASITag = SparcASITag::lookupASITagByAltName(ASIName);
+  Parser.Lex(); // Eat the identifier token.
+
+  if (!ASITag)
+    return Error(TagStart, "unknown ASI tag");
+
+  ASIVal = ASITag->Encoding;
+
   Operands.push_back(SparcOperand::CreateASITag(ASIVal, S, E));
   return ParseStatus::Success;
 }
@@ -1120,35 +1128,32 @@ ParseStatus SparcAsmParser::parsePrefetchTag(OperandVector &Operands) {
   SMLoc E = Parser.getTok().getEndLoc();
   int64_t PrefetchVal = 0;
 
-  switch (getLexer().getKind()) {
-  case AsmToken::LParen:
-  case AsmToken::Integer:
-  case AsmToken::Identifier:
-  case AsmToken::Plus:
-  case AsmToken::Minus:
-  case AsmToken::Tilde:
-    if (getParser().parseAbsoluteExpression(PrefetchVal) ||
-        !isUInt<5>(PrefetchVal))
-      return Error(S, "invalid prefetch number, must be between 0 and 31");
-    break;
-  case AsmToken::Hash: {
-    SMLoc TagStart = getLexer().peekTok(false).getLoc();
-    Parser.Lex(); // Eat the '#'.
-    const StringRef PrefetchName = Parser.getTok().getString();
-    const SparcPrefetchTag::PrefetchTag *PrefetchTag =
-        SparcPrefetchTag::lookupPrefetchTagByName(PrefetchName);
-    Parser.Lex(); // Eat the identifier token.
+  if (getLexer().getKind() != AsmToken::Hash) {
+    // If the prefetch tag provided is not a named tag, then it
+    // must be a constant expression.
+    ParseStatus ParseExprStatus = parseExpression(PrefetchVal);
+    if (!ParseExprStatus.isSuccess())
+      return ParseExprStatus;
 
-    if (!PrefetchTag)
-      return Error(TagStart, "unknown prefetch tag");
+    if (!isUInt<8>(PrefetchVal))
+      return Error(S, "invalid prefetch number, must be between 0 and 31");
 
-    PrefetchVal = PrefetchTag->Encoding;
-    break;
-  }
-  default:
-    return ParseStatus::NoMatch;
+    Operands.push_back(SparcOperand::CreatePrefetchTag(PrefetchVal, S, E));
+    return ParseStatus::Success;
   }
 
+  SMLoc TagStart = getLexer().peekTok(false).getLoc();
+  Parser.Lex(); // Eat the '#'.
+  const StringRef PrefetchName = Parser.getTok().getString();
+  const SparcPrefetchTag::PrefetchTag *PrefetchTag =
+      SparcPrefetchTag::lookupPrefetchTagByName(PrefetchName);
+  Parser.Lex(); // Eat the identifier token.
+
+  if (!PrefetchTag)
+    return Error(TagStart, "unknown prefetch tag");
+
+  PrefetchVal = PrefetchTag->Encoding;
+
   Operands.push_back(SparcOperand::CreatePrefetchTag(PrefetchVal, S, E));
   return ParseStatus::Success;
 }
@@ -1230,8 +1235,12 @@ ParseStatus SparcAsmParser::parseOperand(OperandVector &Operands,
     // Parse an optional address-space identifier after the address.
     // This will be either an immediate constant expression, or, on 64-bit
     // processors, the %asi register.
-    if (is64Bit() && getLexer().is(AsmToken::Percent)) {
+    if (getLexer().is(AsmToken::Percent)) {
       SMLoc S = Parser.getTok().getLoc();
+      if (!is64Bit())
+        return Error(
+            S, "malformed ASI tag, must be a constant integer expression");
+
       Parser.Lex(); // Eat the %.
       const AsmToken Tok = Parser.getTok();
       if (Tok.is(AsmToken::Identifier) && Tok.getString() == "asi") {
@@ -1360,6 +1369,15 @@ ParseStatus SparcAsmParser::parseBranchModifiers(OperandVector &Operands) {
   return ParseStatus::Success;
 }
 
+ParseStatus SparcAsmParser::parseExpression(int64_t &Val) {
+  AsmToken Tok = getLexer().getTok();
+
+  if (!isPossibleExpression(Tok))
+    return ParseStatus::NoMatch;
+
+  return getParser().parseAbsoluteExpression(Val);
+}
+
 #define GET_REGISTER_MATCHER
 #include "SparcGenAsmMatcher.inc"
 
@@ -1590,6 +1608,20 @@ bool SparcAsmParser::matchSparcAsmModifiers(const MCExpr *&EVal,
   return true;
 }
 
+bool SparcAsmParser::isPossibleExpression(const AsmToken &Token) {
+  switch (Token.getKind()) {
+  case AsmToken::LParen:
+  case AsmToken::Integer:
+  case AsmToken::Identifier:
+  case AsmToken::Plus:
+  case AsmToken::Minus:
+  case AsmToken::Tilde:
+    return true;
+  default:
+    return false;
+  }
+}
+
 extern "C" LLVM_EXTERNAL_VISIBILITY void LLVMInitializeSparcAsmParser() {
   RegisterMCAsmParser<SparcAsmParser> A(getTheSparcTarget());
   RegisterMCAsmParser<SparcAsmParser> B(getTheSparcV9Target());
diff --git a/llvm/test/MC/Sparc/sparc-mem-asi-instructions.s b/llvm/test/MC/Sparc/sparc-mem-asi-instructions.s
index 39abe7b..8b8503c 100644
--- a/llvm/test/MC/Sparc/sparc-mem-asi-instructions.s
+++ b/llvm/test/MC/Sparc/sparc-mem-asi-instructions.s
@@ -1,9 +1,9 @@
 ! RUN: not llvm-mc %s -triple=sparc   -show-encoding 2>&1 | FileCheck %s --check-prefix=V8
 ! RUN: not llvm-mc %s -triple=sparcv9 -show-encoding 2>&1 | FileCheck %s --check-prefix=V9
 
-! V8: error: malformed ASI tag, must be a constant integer expression
+! V8: error: expected absolute expression
 ! V8-NEXT: lduba [%i0] asi, %o2
-! V9: error: malformed ASI tag, must be %asi, a constant integer expression, or a named tag
+! V9: error: unexpected token
 ! V9-NEXT: lduba [%i0] asi, %o2
 lduba [%i0] asi, %o2
 
diff --git a/llvm/test/MC/Sparc/sparcv9-instructions.s b/llvm/test/MC/Sparc/sparcv9-instructions.s
index 1b11171..a7761c1 100644
--- a/llvm/test/MC/Sparc/sparcv9-instructions.s
+++ b/llvm/test/MC/Sparc/sparcv9-instructions.s
@@ -657,12 +657,12 @@
         ! V9: prefetcha [%i1+3968] %asi, #one_read    ! encoding: [0xc3,0xee,0x6f,0x80]
         prefetcha  [ %i1 + 0xf80 ] %asi, #one_read
 
-        ! V8:      error: malformed ASI tag, must be a constant integer expression
+        ! V8:      error: invalid operand for instruction
         ! V8-NEXT: prefetcha  [ %i1 + %i2 ] #ASI_SNF, 1
         ! V9: prefetcha [%i1+%i2] #ASI_SNF, #one_read ! encoding: [0xc3,0xee,0x50,0x7a]
         prefetcha  [ %i1 + %i2 ] #ASI_SNF, 1
 
-        ! V8:      error: malformed ASI tag, must be a constant integer expression
+        ! V8:      error: unexpected token
         ! V8-NEXT: prefetcha  [ %i1 + %i2 ] #ASI_SNF, #one_read
         ! V9: prefetcha [%i1+%i2] #ASI_SNF, #one_read ! encoding: [0xc3,0xee,0x50,0x7a]
         prefetcha  [ %i1 + %i2 ] #ASI_SNF, #one_read