Add support for __declspec(code_seg("segname"))

This patch uses CodeSegAttr to represent __declspec(code_seg) rather than 
building on the existing support for #pragma code_seg.
The code_seg declspec is applied on functions and classes. This attribute 
enables the placement of code into separate named segments, including compiler-
generated codes and template instantiations.

For more information, please see the following:
https://msdn.microsoft.com/en-us/library/dn636922.aspx

This patch fixes the regression for the support for attribute ((section).
https://github.com/llvm-mirror/clang/commit/746b78de7812bc785fbb5207b788348040b23fa7

Patch by Soumi Manna (Manna)
Differential Revision: https://reviews.llvm.org/D48841

llvm-svn: 337420

4 files changed, 33 insertions, 2 deletions

diff --git a/clang/include/clang/Basic/Attr.td b/clang/include/clang/Basic/Attr.td
index 0219c715d3a..36c980029c0 100644
--- a/clang/include/clang/Basic/Attr.td
+++ b/clang/include/clang/Basic/Attr.td
@@ -1770,6 +1770,13 @@ def Section : InheritableAttr {
   let Documentation = [SectionDocs];
 }
 
+def CodeSeg : InheritableAttr {
+  let Spellings = [Declspec<"code_seg">];
+  let Args = [StringArgument<"Name">];
+  let Subjects = SubjectList<[Function, CXXRecord], ErrorDiag>;
+  let Documentation = [CodeSegDocs];
+}
+
 def PragmaClangBSSSection : InheritableAttr {
   // This attribute has no spellings as it is only ever created implicitly.
   let Spellings = [];
diff --git a/clang/include/clang/Basic/AttrDocs.td b/clang/include/clang/Basic/AttrDocs.td
index 15aa77e3572..ecaf95a9334 100644
--- a/clang/include/clang/Basic/AttrDocs.td
+++ b/clang/include/clang/Basic/AttrDocs.td
@@ -306,6 +306,18 @@ An example of how to use ``alloc_size``
   }];
 }
 
+def CodeSegDocs : Documentation {
+  let Category = DocCatFunction;
+  let Content = [{
+The ``__declspec(code_seg)`` attribute enables the placement of code into separate
+named segments that can be paged or locked in memory individually. This attribute
+is used to control the placement of instantiated templates and compiler-generated
+code. See the documentation for `__declspec(code_seg)`_ on MSDN.
+
+.. _`__declspec(code_seg)`: http://msdn.microsoft.com/en-us/library/dn636922.aspx
+  }];
+}
+
 def AllocAlignDocs : Documentation {
   let Category = DocCatFunction;
   let Content = [{
diff --git a/clang/include/clang/Basic/DiagnosticSemaKinds.td b/clang/include/clang/Basic/DiagnosticSemaKinds.td
index e441f7b8f52..28eb36b056c 100644
--- a/clang/include/clang/Basic/DiagnosticSemaKinds.td
+++ b/clang/include/clang/Basic/DiagnosticSemaKinds.td
@@ -2668,11 +2668,19 @@ def err_only_annotate_after_access_spec : Error<
   "access specifier can only have annotation attributes">;
 
 def err_attribute_section_invalid_for_target : Error<
-  "argument to 'section' attribute is not valid for this target: %0">;
+  "argument to %select{'code_seg'|'section'}1 attribute is not valid for this target: %0">;
 def warn_mismatched_section : Warning<
-  "section does not match previous declaration">, InGroup<Section>;
+  "%select{codeseg|section}0 does not match previous declaration">, InGroup<Section>;
 def warn_attribute_section_on_redeclaration : Warning<
   "section attribute is specified on redeclared variable">, InGroup<Section>;
+def err_mismatched_code_seg_base : Error<
+  "derived class must specify the same code segment as its base classes">;
+def err_mismatched_code_seg_override : Error<
+  "overriding virtual function must specify the same code segment as its overridden function">;
+def err_conflicting_codeseg_attribute : Error<
+  "conflicting code segment specifiers">;
+def warn_duplicate_codeseg_attribute : Warning<
+  "duplicate code segment specifiers">, InGroup<Section>;
 
 def err_anonymous_property: Error<
   "anonymous property is not supported">;
diff --git a/clang/include/clang/Sema/Sema.h b/clang/include/clang/Sema/Sema.h
index f13e423cef8..4ef982e24f8 100644
--- a/clang/include/clang/Sema/Sema.h
+++ b/clang/include/clang/Sema/Sema.h
@@ -1952,6 +1952,7 @@ public:
   bool shouldLinkDependentDeclWithPrevious(Decl *D, Decl *OldDecl);
   void CheckMain(FunctionDecl *FD, const DeclSpec &D);
   void CheckMSVCRTEntryPoint(FunctionDecl *FD);
+  Attr *getImplicitCodeSegOrSectionAttrForFunction(const FunctionDecl *FD, bool IsDefinition);
   Decl *ActOnParamDeclarator(Scope *S, Declarator &D);
   ParmVarDecl *BuildParmVarDeclForTypedef(DeclContext *DC,
                                           SourceLocation Loc,
@@ -2446,6 +2447,8 @@ public:
                               int FirstArg, unsigned AttrSpellingListIndex);
   SectionAttr *mergeSectionAttr(Decl *D, SourceRange Range, StringRef Name,
                                 unsigned AttrSpellingListIndex);
+  CodeSegAttr *mergeCodeSegAttr(Decl *D, SourceRange Range, StringRef Name,
+                                unsigned AttrSpellingListIndex);
   AlwaysInlineAttr *mergeAlwaysInlineAttr(Decl *D, SourceRange Range,
                                           IdentifierInfo *Ident,
                                           unsigned AttrSpellingListIndex);
@@ -5852,6 +5855,7 @@ public:
   /// ensure that referenceDLLExportedClassMethods is called some point later
   /// when all outer classes of Class are complete.
   void checkClassLevelDLLAttribute(CXXRecordDecl *Class);
+  void checkClassLevelCodeSegAttribute(CXXRecordDecl *Class);
 
   void referenceDLLExportedClassMethods();