[clang] 8298899 - [ASTMatchers][NFC] Use SmallVector when building variadic matcher descriptor

[Nathan James via cfe-commits]

Author: Nathan James
Date: 2021-03-23T16:38:45Z
New Revision: 8298899e56cdf89c68215853010352c45398ab10

URL: https://github.com/llvm/llvm-project/commit/8298899e56cdf89c68215853010352c45398ab10
DIFF: https://github.com/llvm/llvm-project/commit/8298899e56cdf89c68215853010352c45398ab10.diff

LOG: [ASTMatchers][NFC] Use SmallVector when building variadic matcher descriptor

Saves having to manually deallocate storage and keeps InnerArgs will have good cache locality.

Reviewed By: aaron.ballman

Differential Revision: https://reviews.llvm.org/D99106

Added: 
    

Modified: 
    clang/lib/ASTMatchers/Dynamic/Marshallers.h

Removed: 
    


################################################################################
diff  --git a/clang/lib/ASTMatchers/Dynamic/Marshallers.h b/clang/lib/ASTMatchers/Dynamic/Marshallers.h
index 3ffa0d6af217..783fb203c408 100644
--- a/clang/lib/ASTMatchers/Dynamic/Marshallers.h
+++ b/clang/lib/ASTMatchers/Dynamic/Marshallers.h
@@ -492,9 +492,11 @@ template <typename ResultT, typename ArgT,
 VariantMatcher
 variadicMatcherDescriptor(StringRef MatcherName, SourceRange NameRange,
                           ArrayRef<ParserValue> Args, Diagnostics *Error) {
-  ArgT **InnerArgs = new ArgT *[Args.size()]();
+  SmallVector<ArgT *, 8> InnerArgsPtr;
+  InnerArgsPtr.resize_for_overwrite(Args.size());
+  SmallVector<ArgT, 8> InnerArgs;
+  InnerArgs.reserve(Args.size());
 
-  bool HasError = false;
   for (size_t i = 0, e = Args.size(); i != e; ++i) {
     using ArgTraits = ArgTypeTraits<ArgT>;
 
@@ -503,8 +505,7 @@ variadicMatcherDescriptor(StringRef MatcherName, SourceRange NameRange,
     if (!ArgTraits::hasCorrectType(Value)) {
       Error->addError(Arg.Range, Error->ET_RegistryWrongArgType)
           << (i + 1) << ArgTraits::getKind().asString() << Value.getTypeAsString();
-      HasError = true;
-      break;
+      return {};
     }
     if (!ArgTraits::hasCorrectValue(Value)) {
       if (llvm::Optional<std::string> BestGuess =
@@ -521,24 +522,12 @@ variadicMatcherDescriptor(StringRef MatcherName, SourceRange NameRange,
             << (i + 1) << ArgTraits::getKind().asString()
             << Value.getTypeAsString();
       }
-      HasError = true;
-      break;
+      return {};
     }
-
-    InnerArgs[i] = new ArgT(ArgTraits::get(Value));
-  }
-
-  VariantMatcher Out;
-  if (!HasError) {
-    Out = outvalueToVariantMatcher(Func(llvm::makeArrayRef(InnerArgs,
-                                                           Args.size())));
+    InnerArgs.set_size(i + 1);
+    InnerArgsPtr[i] = new (&InnerArgs[i]) ArgT(ArgTraits::get(Value));
   }
-
-  for (size_t i = 0, e = Args.size(); i != e; ++i) {
-    delete InnerArgs[i];
-  }
-  delete[] InnerArgs;
-  return Out;
+  return outvalueToVariantMatcher(Func(InnerArgsPtr));
 }
 
 /// Matcher descriptor for variadic functions.