[PATCH] D36487: Emit section information for extern variables.

[Erich Keane via Phabricator via cfe-commits]

This revision was automatically updated to reflect the committed changes.
Closed by commit rL314262: Emit section information for extern variables.  (authored by erichkeane).

Changed prior to commit:
  https://reviews.llvm.org/D36487?vs=116581&id=116739#toc

Repository:
  rL LLVM

https://reviews.llvm.org/D36487

Files:
  cfe/trunk/include/clang/Basic/DiagnosticSemaKinds.td
  cfe/trunk/lib/CodeGen/CodeGenModule.cpp
  cfe/trunk/lib/Sema/SemaDecl.cpp
  cfe/trunk/test/Sema/attr-section.c


Index: cfe/trunk/lib/CodeGen/CodeGenModule.cpp
===================================================================
--- cfe/trunk/lib/CodeGen/CodeGenModule.cpp
+++ cfe/trunk/lib/CodeGen/CodeGenModule.cpp
@@ -2432,6 +2432,12 @@
       EmitGlobalVarDefinition(D);
     }
 
+    // Emit section information for extern variables.
+    if (D->hasExternalStorage()) {
+      if (const SectionAttr *SA = D->getAttr<SectionAttr>())
+        GV->setSection(SA->getName());
+    }
+
     // Handle XCore specific ABI requirements.
     if (getTriple().getArch() == llvm::Triple::xcore &&
         D->getLanguageLinkage() == CLanguageLinkage &&
Index: cfe/trunk/lib/Sema/SemaDecl.cpp
===================================================================
--- cfe/trunk/lib/Sema/SemaDecl.cpp
+++ cfe/trunk/lib/Sema/SemaDecl.cpp
@@ -2607,6 +2607,16 @@
     }
   }
 
+  // This redeclaration adds a section attribute.
+  if (New->hasAttr<SectionAttr>() && !Old->hasAttr<SectionAttr>()) {
+    if (auto *VD = dyn_cast<VarDecl>(New)) {
+      if (VD->isThisDeclarationADefinition() != VarDecl::Definition) {
+        Diag(New->getLocation(), diag::warn_attribute_section_on_redeclaration);
+        Diag(Old->getLocation(), diag::note_previous_declaration);
+      }
+    }
+  }
+
   if (!Old->hasAttrs())
     return;
 
Index: cfe/trunk/include/clang/Basic/DiagnosticSemaKinds.td
===================================================================
--- cfe/trunk/include/clang/Basic/DiagnosticSemaKinds.td
+++ cfe/trunk/include/clang/Basic/DiagnosticSemaKinds.td
@@ -2620,6 +2620,8 @@
   "argument to 'section' attribute is not valid for this target: %0">;
 def warn_mismatched_section : Warning<
   "section 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_anonymous_property: Error<
   "anonymous property is not supported">;
Index: cfe/trunk/test/Sema/attr-section.c
===================================================================
--- cfe/trunk/test/Sema/attr-section.c
+++ cfe/trunk/test/Sema/attr-section.c
@@ -19,3 +19,7 @@
 void __attribute__((section("bar,zed"))) test2(void) {} // expected-warning {{section does not match previous declaration}}
 
 enum __attribute__((section("NEAR,x"))) e { one }; // expected-error {{'section' attribute only applies to functions, methods, properties, and global variables}}
+
+extern int a; // expected-note {{previous declaration is here}}
+int *b = &a;
+extern int a __attribute__((section("foo,zed"))); // expected-warning {{section attribute is specified on redeclared variable}}


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