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



git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@337420 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 67 insertions, 2 deletions

diff --git a/lib/Sema/SemaDeclAttr.cpp b/lib/Sema/SemaDeclAttr.cpp
index 47ef872e43..f549aa0468 100644
--- a/lib/Sema/SemaDeclAttr.cpp
+++ b/lib/Sema/SemaDeclAttr.cpp
@@ -2825,10 +2825,18 @@ static void handleVecTypeHint(Sema &S, Decl *D, const ParsedAttr &AL) {
 SectionAttr *Sema::mergeSectionAttr(Decl *D, SourceRange Range,
                                     StringRef Name,
                                     unsigned AttrSpellingListIndex) {
+  // Explicit or partial specializations do not inherit
+  // the section attribute from the primary template.
+  if (const auto *FD = dyn_cast<FunctionDecl>(D)) {
+    if (AttrSpellingListIndex == SectionAttr::Declspec_allocate &&
+        FD->isFunctionTemplateSpecialization())
+      return nullptr;
+  }
   if (SectionAttr *ExistingAttr = D->getAttr<SectionAttr>()) {
     if (ExistingAttr->getName() == Name)
       return nullptr;
-    Diag(ExistingAttr->getLocation(), diag::warn_mismatched_section);
+    Diag(ExistingAttr->getLocation(), diag::warn_mismatched_section)
+         << 1 /*section*/;
     Diag(Range.getBegin(), diag::note_previous_attribute);
     return nullptr;
   }
@@ -2839,7 +2847,8 @@ SectionAttr *Sema::mergeSectionAttr(Decl *D, SourceRange Range,
 bool Sema::checkSectionName(SourceLocation LiteralLoc, StringRef SecName) {
   std::string Error = Context.getTargetInfo().isValidSectionSpecifier(SecName);
   if (!Error.empty()) {
-    Diag(LiteralLoc, diag::err_attribute_section_invalid_for_target) << Error;
+    Diag(LiteralLoc, diag::err_attribute_section_invalid_for_target) << Error
+         << 1 /*'section'*/;	  
     return false;
   }
   return true;
@@ -2870,6 +2879,59 @@ static void handleSectionAttr(Sema &S, Decl *D, const ParsedAttr &AL) {
     D->addAttr(NewAttr);
 }
 
+static bool checkCodeSegName(Sema&S, SourceLocation LiteralLoc, StringRef CodeSegName) {
+  std::string Error = S.Context.getTargetInfo().isValidSectionSpecifier(CodeSegName);
+  if (!Error.empty()) {
+    S.Diag(LiteralLoc, diag::err_attribute_section_invalid_for_target) << Error
+           << 0 /*'code-seg'*/;
+    return false;
+  }
+  return true;
+}
+
+CodeSegAttr *Sema::mergeCodeSegAttr(Decl *D, SourceRange Range,
+                                    StringRef Name,
+                                    unsigned AttrSpellingListIndex) {
+  // Explicit or partial specializations do not inherit
+  // the code_seg attribute from the primary template.
+  if (const auto *FD = dyn_cast<FunctionDecl>(D)) {
+    if (FD->isFunctionTemplateSpecialization())
+      return nullptr;
+  }
+  if (const auto *ExistingAttr = D->getAttr<CodeSegAttr>()) {
+    if (ExistingAttr->getName() == Name)
+      return nullptr;
+    Diag(ExistingAttr->getLocation(), diag::warn_mismatched_section)
+         << 0 /*codeseg*/;
+    Diag(Range.getBegin(), diag::note_previous_attribute);
+    return nullptr;
+  }
+  return ::new (Context) CodeSegAttr(Range, Context, Name,
+                                     AttrSpellingListIndex);
+}
+
+static void handleCodeSegAttr(Sema &S, Decl *D, const ParsedAttr &AL) {
+  StringRef Str;
+  SourceLocation LiteralLoc;
+  if (!S.checkStringLiteralArgumentAttr(AL, 0, Str, &LiteralLoc))
+    return;
+  if (!checkCodeSegName(S, LiteralLoc, Str))
+    return;
+  if (const auto *ExistingAttr = D->getAttr<CodeSegAttr>()) {
+    if (!ExistingAttr->isImplicit()) {
+      S.Diag(AL.getLoc(),
+             ExistingAttr->getName() == Str
+             ? diag::warn_duplicate_codeseg_attribute
+             : diag::err_conflicting_codeseg_attribute);
+      return;
+    }
+    D->dropAttr<CodeSegAttr>();
+  }
+  if (CodeSegAttr *CSA = S.mergeCodeSegAttr(D, AL.getRange(), Str,
+                                            AL.getAttributeSpellingListIndex()))
+    D->addAttr(CSA);
+}
+
 // Check for things we'd like to warn about. Multiversioning issues are
 // handled later in the process, once we know how many exist.
 bool Sema::checkTargetAttr(SourceLocation LiteralLoc, StringRef AttrStr) {
@@ -6120,6 +6182,9 @@ static void ProcessDeclAttribute(Sema &S, Scope *scope, Decl *D,
   case ParsedAttr::AT_Section:
     handleSectionAttr(S, D, AL);
     break;
+  case ParsedAttr::AT_CodeSeg:
+    handleCodeSegAttr(S, D, AL);
+    break;
   case ParsedAttr::AT_Target:
     handleTargetAttr(S, D, AL);
     break;