[Lexer] Fix invalid suffix diagnostic for fixed-point literals

Committing on behalf of nagart, who authored this patch.

Differential Revision: https://reviews.llvm.org/D80412

clang/include/clang/Basic/DiagnosticLexKinds.td

@@ -175,7 +175,7 @@ def ext_unknown_escape : ExtWarn<"unknown escape sequence '\\%0'">,
 def err_invalid_digit : Error<
   "invalid digit '%0' in %select{decimal|octal|binary}1 constant">;
 def err_invalid_suffix_constant : Error<
-  "invalid suffix '%0' on %select{integer|floating}1 constant">;
+  "invalid suffix '%0' on %select{integer|floating|fixed-point}1 constant">;
 def warn_cxx11_compat_digit_separator : Warning<
   "digit separators are incompatible with C++ standards before C++14">,
   InGroup<CXXPre14Compat>, DefaultIgnore;

clang/include/clang/Lex/LiteralSupport.h

@@ -71,7 +71,9 @@ class NumericLiteralParser {
   bool isFract : 1;         // 1.0hr/r/lr/uhr/ur/ulr
   bool isAccum : 1;         // 1.0hk/k/lk/uhk/uk/ulk
 
-  bool isFixedPointLiteral() const { return saw_fixed_point_suffix; }
+  bool isFixedPointLiteral() const {
+    return (saw_period || saw_exponent) && saw_fixed_point_suffix;
+  }
 
   bool isIntegerLiteral() const {
     return !saw_period && !saw_exponent && !isFixedPointLiteral();

clang/lib/Lex/LiteralSupport.cpp

@@ -583,6 +583,7 @@ NumericLiteralParser::NumericLiteralParser(StringRef TokSpelling,
 
   // Parse the suffix.  At this point we can classify whether we have an FP or
   // integer constant.
+  bool isFixedPointConstant = isFixedPointLiteral();
   bool isFPConstant = isFloatingLiteral();
 
   // Loop over all of the characters of the suffix.  If we see something bad,
@@ -737,7 +738,8 @@ NumericLiteralParser::NumericLiteralParser(StringRef TokSpelling,
       // Report an error if there are any.
       PP.Diag(PP.AdvanceToTokenCharacter(TokLoc, SuffixBegin - ThisTokBegin),
               diag::err_invalid_suffix_constant)
-          << StringRef(SuffixBegin, ThisTokEnd - SuffixBegin) << isFPConstant;
+          << StringRef(SuffixBegin, ThisTokEnd - SuffixBegin)
+          << (isFixedPointConstant ? 2 : isFPConstant);
       hadError = true;
     }
   }

clang/test/Frontend/fixed_point_errors.c

@@ -137,15 +137,15 @@ _Sat longfract_t td_sat_long_fract;         // expected-error{{'_Sat' specifier
 _Sat longaccum_t td_sat_long_accum;         // expected-error{{'_Sat' specifier is only valid on '_Fract' or '_Accum', not 'type-name'}}
 
 /* Bad suffixes  */
-_Accum fk = 1.0fk;    // expected-error{{invalid suffix 'fk' on integer constant}}
-_Accum kk = 1.0kk;    // expected-error{{invalid suffix 'kk' on integer constant}}
-_Accum rk = 1.0rk;    // expected-error{{invalid suffix 'rk' on integer constant}}
-_Accum rk = 1.0rr;    // expected-error{{invalid suffix 'rr' on integer constant}}
-_Accum qk = 1.0qr;    // expected-error{{invalid suffix 'qr' on integer constant}}
+_Accum fk = 1.0fk; // expected-error{{invalid suffix 'fk' on fixed-point constant}}
+_Accum kk = 1.0kk; // expected-error{{invalid suffix 'kk' on fixed-point constant}}
+_Accum rk = 1.0rk; // expected-error{{invalid suffix 'rk' on fixed-point constant}}
+_Accum rk = 1.0rr; // expected-error{{invalid suffix 'rr' on fixed-point constant}}
+_Accum qk = 1.0qr; // expected-error{{invalid suffix 'qr' on fixed-point constant}}
 
 /* Using wrong exponent notation */
-_Accum dec_with_hex_exp1 = 0.1p10k;    // expected-error{{invalid suffix 'p10k' on integer constant}}
-_Accum dec_with_hex_exp2 = 0.1P10k;    // expected-error{{invalid suffix 'P10k' on integer constant}}
+_Accum dec_with_hex_exp1 = 0.1p10k;    // expected-error{{invalid suffix 'p10k' on fixed-point constant}}
+_Accum dec_with_hex_exp2 = 0.1P10k;    // expected-error{{invalid suffix 'P10k' on fixed-point constant}}
 _Accum hex_with_dex_exp1 = 0x0.1e10k;  // expected-error{{hexadecimal floating constant requires an exponent}}
 _Accum hex_with_dex_exp2 = 0x0.1E10k;  // expected-error{{hexadecimal floating constant requires an exponent}}