Implement section pragma feedback on r205810

Mostly short-circuits some conditionals.  Adds target validation of
sections passed to these pragmas.

llvm-svn: 231317

clang/include/clang/Sema/Sema.h

@@ -2822,6 +2822,7 @@ public:
   bool checkStringLiteralArgumentAttr(const AttributeList &Attr,
                                       unsigned ArgNum, StringRef &Str,
                                       SourceLocation *ArgLocation = nullptr);
+  bool checkSectionName(SourceLocation LiteralLoc, StringRef Str);
   bool checkMSInheritanceAttrOnDefinition(
       CXXRecordDecl *RD, SourceRange Range, bool BestCase,
       MSInheritanceAttr::Spelling SemanticSpelling);

clang/lib/Sema/SemaAttr.cpp

@@ -422,6 +422,9 @@ void Sema::ActOnPragmaMSSeg(SourceLocation PragmaLocation,
   if (Action & PSK_Pop && Stack->Stack.empty())
     Diag(PragmaLocation, diag::warn_pragma_pop_failed) << PragmaName
         << "stack empty";
+  if (SegmentName &&
+      !checkSectionName(SegmentName->getLocStart(), SegmentName->getString()))
+    return;
   Stack->Act(PragmaLocation, Action, StackSlotLabel, SegmentName);
 }
 

clang/lib/Sema/SemaDecl.cpp

@@ -7403,7 +7403,8 @@ Sema::ActOnFunctionDeclarator(Scope *S, Declarator &D, DeclContext *DC,
     NewFD->setInvalidDecl();
   }
 
-  if (D.isFunctionDefinition() && CodeSegStack.CurrentValue &&
+  // Apply an implicit SectionAttr if #pragma code_seg is active.
+  if (CodeSegStack.CurrentValue && D.isFunctionDefinition() &&
       !NewFD->hasAttr<SectionAttr>()) {
     NewFD->addAttr(
         SectionAttr::CreateImplicit(Context, SectionAttr::Declspec_allocate,
@@ -9497,7 +9498,9 @@ void Sema::CheckCompleteVariableDeclaration(VarDecl *var) {
 
   }
 
-  if (var->isThisDeclarationADefinition() &&
+  // Apply section attributes and pragmas to global variables.
+  bool GlobalStorage = var->hasGlobalStorage();
+  if (GlobalStorage && var->isThisDeclarationADefinition() &&
       ActiveTemplateInstantiations.empty()) {
     PragmaStack<StringLiteral *> *Stack = nullptr;
     int SectionFlags = ASTContext::PSF_Implicit | ASTContext::PSF_Read;
@@ -9510,11 +9513,11 @@ void Sema::CheckCompleteVariableDeclaration(VarDecl *var) {
       Stack = &DataSegStack;
       SectionFlags |= ASTContext::PSF_Write;
     }
-    if (!var->hasAttr<SectionAttr>() && Stack->CurrentValue)
-      var->addAttr(
-          SectionAttr::CreateImplicit(Context, SectionAttr::Declspec_allocate,
-                                      Stack->CurrentValue->getString(),
-                                      Stack->CurrentPragmaLocation));
+    if (Stack->CurrentValue && !var->hasAttr<SectionAttr>()) {
+      var->addAttr(SectionAttr::CreateImplicit(
+          Context, SectionAttr::Declspec_allocate,
+          Stack->CurrentValue->getString(), Stack->CurrentPragmaLocation));
+    }
     if (const SectionAttr *SA = var->getAttr<SectionAttr>())
       if (UnifySection(SA->getName(), SectionFlags, var))
         var->dropAttr<SectionAttr>();
@@ -9557,7 +9560,7 @@ void Sema::CheckCompleteVariableDeclaration(VarDecl *var) {
   }
 
   Expr *Init = var->getInit();
-  bool IsGlobal = var->hasGlobalStorage() && !var->isStaticLocal();
+  bool IsGlobal = GlobalStorage && !var->isStaticLocal();
   QualType baseType = Context.getBaseElementType(type);
 
   if (!var->getDeclContext()->isDependentContext() &&

clang/lib/Sema/SemaDeclAttr.cpp

@@ -2342,6 +2342,15 @@ SectionAttr *Sema::mergeSectionAttr(Decl *D, SourceRange Range,
                                      AttrSpellingListIndex);
 }
 
+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;
+    return false;
+  }
+  return true;
+}
+
 static void handleSectionAttr(Sema &S, Decl *D, const AttributeList &Attr) {
   // Make sure that there is a string literal as the sections's single
   // argument.
@@ -2350,6 +2359,9 @@ static void handleSectionAttr(Sema &S, Decl *D, const AttributeList &Attr) {
   if (!S.checkStringLiteralArgumentAttr(Attr, 0, Str, &LiteralLoc))
     return;
 
+  if (!S.checkSectionName(LiteralLoc, Str))
+    return;
+
   // If the target wants to validate the section specifier, make it happen.
   std::string Error = S.Context.getTargetInfo().isValidSectionSpecifier(Str);
   if (!Error.empty()) {