Fixed DSLParser assertion error uncovered by fuzzer

Bug: oss-fuzz:38108
Change-Id: I0e055d837923f00b982bc395dbf29b6ff59a3b21
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/448896
Commit-Queue: Ethan Nicholas <ethannicholas@google.com>
Reviewed-by: John Stiles <johnstiles@google.com>

gn/sksl_tests.gni

@@ -104,6 +104,7 @@ sksl_error_tests = [
   "/sksl/errors/Ossfuzz37620.sksl",
   "/sksl/errors/Ossfuzz38106.sksl",
   "/sksl/errors/Ossfuzz38107.sksl",
+  "/sksl/errors/Ossfuzz38108.sksl",
   "/sksl/errors/Ossfuzz38140.sksl",
   "/sksl/errors/Ossfuzz38560.sksl",
   "/sksl/errors/Ossfuzz38865.sksl",

include/sksl/DSLSymbols.h

@@ -57,7 +57,7 @@ bool IsType(skstd::string_view name);
 /**
  * Adds a variable to the current symbol table.
  */
-void AddToSymbolTable(DSLVarBase& var);
+void AddToSymbolTable(DSLVarBase& var, PositionInfo pos = PositionInfo::Capture());
 
 } // namespace dsl
 

resources/sksl/errors/DuplicateSymbol.sksl

@@ -2,4 +2,6 @@ int x;
 int x;
 
 int main;
-void main() {}
+void main() {
+    int y,y;
+}

resources/sksl/errors/Ossfuzz38108.sksl

@@ -0,0 +1 @@
+int a,a;

src/sksl/SkSLCompiler.cpp

@@ -884,6 +884,7 @@ bool Compiler::toSPIRV(Program& program, OutputStream& out) {
                 errors.append(disassembly);
             }
             this->errorReporter().error(-1, errors);
+            this->errorReporter().reportPendingErrors(PositionInfo());
 #else
             SkDEBUGFAILF("%s", errors.c_str());
 #endif
@@ -957,7 +958,6 @@ void Compiler::handleError(skstd::string_view msg, PositionInfo pos) {
 }
 
 String Compiler::errorText(bool showCount) {
-    this->errorReporter().reportPendingErrors(PositionInfo());
     if (showCount) {
         this->writeErrorCount();
     }

src/sksl/SkSLDSLParser.cpp

@@ -450,7 +450,7 @@ void DSLParser::globalVarDeclarationEnd(PositionInfo pos, const dsl::DSLModifier
         }
         DSLGlobalVar next(mods, type, this->text(identifierName), std::move(anotherInitializer));
         Declare(next);
-        AddToSymbolTable(next);
+        AddToSymbolTable(next, this->position(identifierName));
     }
     this->expect(Token::Kind::TK_SEMICOLON, "';'");
 }
@@ -486,7 +486,7 @@ DSLStatement DSLParser::localVarDeclarationEnd(PositionInfo pos, const dsl::DSLM
         }
         DSLVar next(mods, type, this->text(identifierName), std::move(anotherInitializer));
         DSLWriter::AddVarDeclaration(result, next);
-        AddToSymbolTable(next);
+        AddToSymbolTable(next, this->position(identifierName));
     }
     this->expect(Token::Kind::TK_SEMICOLON, "';'");
     return result;

src/sksl/dsl/DSLSymbols.cpp

@@ -35,11 +35,12 @@ bool IsType(skstd::string_view name) {
     return s && s->is<Type>();
 }
 
-void AddToSymbolTable(DSLVarBase& var) {
+void AddToSymbolTable(DSLVarBase& var, PositionInfo pos) {
     const SkSL::Variable* skslVar = DSLWriter::Var(var);
     if (skslVar) {
         CurrentSymbolTable()->addWithoutOwnership(skslVar);
     }
+    DSLWriter::ReportErrors(pos);
 }
 
 const String* Retain(String string) {

tests/sksl/errors/DuplicateSymbol.glsl

@@ -2,4 +2,5 @@
 
 error: 2: symbol 'x' was already defined
 error: 5: symbol 'main' was already defined
-2 errors
+error: 6: symbol 'y' was already defined
+3 errors

tests/sksl/errors/Ossfuzz38108.glsl

@@ -0,0 +1,4 @@
+### Compilation failed:
+
+error: 1: symbol 'a' was already defined
+1 error