1 files changed, 28 insertions, 16 deletions

diff --git a/llvm/lib/AsmParser/LLLexer.cpp b/llvm/lib/AsmParser/LLLexer.cpp
index a3e47da77fe7..f71cbe1b4b1e 100644
--- a/llvm/lib/AsmParser/LLLexer.cpp
+++ b/llvm/lib/AsmParser/LLLexer.cpp
@@ -25,9 +25,21 @@
 
 using namespace llvm;
 
-bool LLLexer::Error(LocTy ErrorLoc, const Twine &Msg) const {
-  ErrorInfo = SM.GetMessage(ErrorLoc, SourceMgr::DK_Error, Msg);
-  return true;
+// Both the lexer and parser can issue error messages. If the lexer issues a
+// lexer error, since we do not terminate execution immediately, usually that
+// is followed by the parser issuing a parser error. However, the error issued
+// by the lexer is more relevant in that case as opposed to potentially more
+// generic parser error. So instead of always recording the last error message
+// use the `Priority` to establish a priority, with Lexer > Parser > None. We
+// record the issued message only if the message has same or higher priority
+// than the existing one. This prevents lexer errors from being overwritten by
+// parser errors.
+void LLLexer::Error(LocTy ErrorLoc, const Twine &Msg,
+                    LLLexer::ErrorPriority Priority) {
+  if (Priority < ErrorInfo.Priority)
+    return;
+  ErrorInfo.Error = SM.GetMessage(ErrorLoc, SourceMgr::DK_Error, Msg);
+  ErrorInfo.Priority = Priority;
 }
 
 void LLLexer::Warning(LocTy WarningLoc, const Twine &Msg) const {
@@ -49,7 +61,7 @@ uint64_t LLLexer::atoull(const char *Buffer, const char *End) {
     Result *= 10;
     Result += *Buffer-'0';
     if (Result < OldRes) {  // Uh, oh, overflow detected!!!
-      Error("constant bigger than 64 bits detected!");
+      LexError("constant bigger than 64 bits detected!");
       return 0;
     }
   }
@@ -64,7 +76,7 @@ uint64_t LLLexer::HexIntToVal(const char *Buffer, const char *End) {
     Result += hexDigitValue(*Buffer);
 
     if (Result < OldRes) {   // Uh, oh, overflow detected!!!
-      Error("constant bigger than 64 bits detected!");
+      LexError("constant bigger than 64 bits detected!");
       return 0;
     }
   }
@@ -87,7 +99,7 @@ void LLLexer::HexToIntPair(const char *Buffer, const char *End,
     Pair[1] += hexDigitValue(*Buffer);
   }
   if (Buffer != End)
-    Error("constant bigger than 128 bits detected!");
+    LexError("constant bigger than 128 bits detected!");
 }
 
 /// FP80HexToIntPair - translate an 80 bit FP80 number (20 hexits) into
@@ -106,7 +118,7 @@ void LLLexer::FP80HexToIntPair(const char *Buffer, const char *End,
     Pair[0] += hexDigitValue(*Buffer);
   }
   if (Buffer != End)
-    Error("constant bigger than 128 bits detected!");
+    LexError("constant bigger than 128 bits detected!");
 }
 
 // UnEscapeLexed - Run through the specified buffer and change \xx codes to the
@@ -273,14 +285,14 @@ lltok::Kind LLLexer::LexDollar() {
       int CurChar = getNextChar();
 
       if (CurChar == EOF) {
-        Error("end of file in COMDAT variable name");
+        LexError("end of file in COMDAT variable name");
         return lltok::Error;
       }
       if (CurChar == '"') {
         StrVal.assign(TokStart + 2, CurPtr - 1);
         UnEscapeLexed(StrVal);
         if (StringRef(StrVal).contains(0)) {
-          Error("Null bytes are not allowed in names");
+          LexError("Null bytes are not allowed in names");
           return lltok::Error;
         }
         return lltok::ComdatVar;
@@ -302,7 +314,7 @@ lltok::Kind LLLexer::ReadString(lltok::Kind kind) {
     int CurChar = getNextChar();
 
     if (CurChar == EOF) {
-      Error("end of file in string constant");
+      LexError("end of file in string constant");
       return lltok::Error;
     }
     if (CurChar == '"') {
@@ -342,7 +354,7 @@ lltok::Kind LLLexer::LexUIntID(lltok::Kind Token) {
 
   uint64_t Val = atoull(TokStart + 1, CurPtr);
   if ((unsigned)Val != Val)
-    Error("invalid value number (too large)!");
+    LexError("invalid value number (too large)!");
   UIntVal = unsigned(Val);
   return Token;
 }
@@ -356,14 +368,14 @@ lltok::Kind LLLexer::LexVar(lltok::Kind Var, lltok::Kind VarID) {
       int CurChar = getNextChar();
 
       if (CurChar == EOF) {
-        Error("end of file in global variable name");
+        LexError("end of file in global variable name");
         return lltok::Error;
       }
       if (CurChar == '"') {
         StrVal.assign(TokStart+2, CurPtr-1);
         UnEscapeLexed(StrVal);
         if (StringRef(StrVal).contains(0)) {
-          Error("Null bytes are not allowed in names");
+          LexError("Null bytes are not allowed in names");
           return lltok::Error;
         }
         return Var;
@@ -398,7 +410,7 @@ lltok::Kind LLLexer::LexQuote() {
   if (CurPtr[0] == ':') {
     ++CurPtr;
     if (StringRef(StrVal).contains(0)) {
-      Error("Null bytes are not allowed in names");
+      LexError("Null bytes are not allowed in names");
       kind = lltok::Error;
     } else {
       kind = lltok::LabelStr;
@@ -480,7 +492,7 @@ lltok::Kind LLLexer::LexIdentifier() {
     uint64_t NumBits = atoull(StartChar, CurPtr);
     if (NumBits < IntegerType::MIN_INT_BITS ||
         NumBits > IntegerType::MAX_INT_BITS) {
-      Error("bitwidth for integer type out of range!");
+      LexError("bitwidth for integer type out of range!");
       return lltok::Error;
     }
     TyVal = IntegerType::get(Context, NumBits);
@@ -1109,7 +1121,7 @@ lltok::Kind LLLexer::LexDigitOrNegative() {
     uint64_t Val = atoull(TokStart, CurPtr);
     ++CurPtr; // Skip the colon.
     if ((unsigned)Val != Val)
-      Error("invalid value number (too large)!");
+      LexError("invalid value number (too large)!");
     UIntVal = unsigned(Val);
     return lltok::LabelID;
   }