More stack size reduction

Author: cor3ntin

clang/include/clang/Parse/Parser.h

@@ -3844,6 +3844,8 @@ class Parser : public CodeCompletionHandler {
   DeclGroupPtrTy ParseTemplateDeclarationOrSpecialization(
       DeclaratorContext Context, SourceLocation &DeclEnd,
       ParsedAttributes &AccessAttrs, AccessSpecifier AS);
+  clang::Parser::DeclGroupPtrTy ParseTemplateDeclarationOrSpecialization(
+      DeclaratorContext Context, SourceLocation &DeclEnd, AccessSpecifier AS);
   DeclGroupPtrTy ParseDeclarationAfterTemplate(
       DeclaratorContext Context, ParsedTemplateInfo &TemplateInfo,
       ParsingDeclRAIIObject &DiagsFromParams, SourceLocation &DeclEnd,

clang/include/clang/Sema/ParsedAttr.h

@@ -970,6 +970,14 @@ class ParsedAttributes : public ParsedAttributesView {
     pool.takeAllFrom(Other.pool);
   }
 
+  void takeAllAtEndFrom(ParsedAttributes &Other) {
+    assert(&Other != this &&
+           "ParsedAttributes can't take attributes from itself");
+    addAllAtEnd(Other.begin(), Other.end());
+    Other.clearListOnly();
+    pool.takeAllFrom(Other.pool);
+  }
+
   void takeOneFrom(ParsedAttributes &Other, ParsedAttr *PA) {
     assert(&Other != this &&
            "ParsedAttributes can't take attribute from itself");
@@ -1067,10 +1075,11 @@ class ParsedAttributes : public ParsedAttributesView {
   mutable AttributePool pool;
 };
 
-/// Consumes the attributes from `First` and `Second` and concatenates them into
-/// `Result`. Sets `Result.Range` to the combined range of `First` and `Second`.
-void takeAndConcatenateAttrs(ParsedAttributes &First, ParsedAttributes &Second,
-                             ParsedAttributes &Result);
+/// Consumes the attributes from `Second` and concatenates them
+/// at the end of `First`. Sets `First.Range`
+/// to the combined range of `First` and `Second`.
+void takeAndConcatenateAttrs(ParsedAttributes &First,
+                             ParsedAttributes &&Second);
 
 /// These constants match the enumerated choices of
 /// err_attribute_argument_n_type and err_attribute_argument_type.

clang/lib/Parse/ParseDecl.cpp

@@ -2076,10 +2076,9 @@ Parser::DeclGroupPtrTy Parser::ParseDeclaration(DeclaratorContext Context,
     ProhibitAttributes(DeclSpecAttrs);
     return ParseNamespace(Context, DeclEnd);
   case tok::kw_using: {
-    ParsedAttributes Attrs(AttrFactory);
-    takeAndConcatenateAttrs(DeclAttrs, DeclSpecAttrs, Attrs);
+    takeAndConcatenateAttrs(DeclAttrs, std::move(DeclSpecAttrs));
     return ParseUsingDirectiveOrDeclaration(Context, ParsedTemplateInfo(),
-                                            DeclEnd, Attrs);
+                                            DeclEnd, DeclAttrs);
   }
   case tok::kw_static_assert:
   case tok::kw__Static_assert:

clang/lib/Parse/ParseStmt.cpp

@@ -126,11 +126,7 @@ Parser::ParseStatementOrDeclaration(StmtVector &Stmts,
       Stmts, StmtCtx, TrailingElseLoc, CXX11Attrs, GNUOrMSAttrs);
   MaybeDestroyTemplateIds();
 
-  CXX11Attrs.takeAllFrom(GNUOrMSAttrs);
-  if (!CXX11Attrs.Range.getBegin().isValid())
-    CXX11Attrs.Range.setBegin(GNUOrMSAttrs.Range.getBegin());
-  if (GNUOrMSAttrs.Range.getEnd().isValid())
-    CXX11Attrs.Range.setEnd(GNUOrMSAttrs.Range.getEnd());
+  takeAndConcatenateAttrs(CXX11Attrs, std::move(GNUOrMSAttrs));
 
   assert((CXX11Attrs.empty() || Res.isInvalid() || Res.isUsable()) &&
          "attributes on empty statement");
@@ -208,11 +204,10 @@ StmtResult Parser::ParseStatementOrDeclarationAfterAttributes(
       // Both C++11 and GNU attributes preceding the label appertain to the
       // label, so put them in a single list to pass on to
       // ParseLabeledStatement().
-      ParsedAttributes Attrs(AttrFactory);
-      takeAndConcatenateAttrs(CXX11Attrs, GNUAttrs, Attrs);
+      takeAndConcatenateAttrs(CXX11Attrs, std::move(GNUAttrs));
 
       // identifier ':' statement
-      return ParseLabeledStatement(Attrs, StmtCtx);
+      return ParseLabeledStatement(CXX11Attrs, StmtCtx);
     }
 
     // Look up the identifier, and typo-correct it to a keyword if it's not
@@ -303,9 +298,7 @@ StmtResult Parser::ParseStatementOrDeclarationAfterAttributes(
 
   case tok::kw_template: {
     SourceLocation DeclEnd;
-    ParsedAttributes Attrs(AttrFactory);
     ParseTemplateDeclarationOrSpecialization(DeclaratorContext::Block, DeclEnd,
-                                             Attrs,
                                              getAccessSpecifierIfPresent());
     return StmtError();
   }

clang/lib/Parse/ParseTemplate.cpp

@@ -179,6 +179,13 @@ Parser::DeclGroupPtrTy Parser::ParseTemplateDeclarationOrSpecialization(
       Context, TemplateInfo, ParsingTemplateParams, DeclEnd, AccessAttrs, AS);
 }
 
+Parser::DeclGroupPtrTy Parser::ParseTemplateDeclarationOrSpecialization(
+    DeclaratorContext Context, SourceLocation &DeclEnd, AccessSpecifier AS) {
+  ParsedAttributes AccessAttrs(AttrFactory);
+  return ParseTemplateDeclarationOrSpecialization(Context, DeclEnd, AccessAttrs,
+                                                  AS);
+}
+
 /// Parse a single declaration that declares a template,
 /// template specialization, or explicit instantiation of a template.
 ///

clang/lib/Sema/ParsedAttr.cpp

@@ -310,18 +310,13 @@ bool ParsedAttr::checkAtMostNumArgs(Sema &S, unsigned Num) const {
 }
 
 void clang::takeAndConcatenateAttrs(ParsedAttributes &First,
-                                    ParsedAttributes &Second,
-                                    ParsedAttributes &Result) {
-  // Note that takeAllFrom() puts the attributes at the beginning of the list,
-  // so to obtain the correct ordering, we add `Second`, then `First`.
-  Result.takeAllFrom(Second);
-  Result.takeAllFrom(First);
-  if (First.Range.getBegin().isValid())
-    Result.Range.setBegin(First.Range.getBegin());
-  else
-    Result.Range.setBegin(Second.Range.getBegin());
+                                    ParsedAttributes &&Second) {
+
+  First.takeAllAtEndFrom(Second);
+
+  if (!First.Range.getBegin().isValid())
+    First.Range.setBegin(Second.Range.getBegin());
+
   if (Second.Range.getEnd().isValid())
-    Result.Range.setEnd(Second.Range.getEnd());
-  else
-    Result.Range.setEnd(First.Range.getEnd());
+    First.Range.setEnd(Second.Range.getEnd());
 }