Add support for #pragma clang section

This patch provides a means to specify section-names for global variables, 
functions and static variables, using #pragma directives. 
This feature is only defined to work sensibly for ELF targets.
One can specify section names as:
#pragma clang section bss="myBSS" data="myData" rodata="myRodata" text="myText"
One can "unspecify" a section name with empty string e.g.
#pragma clang section bss="" data="" text="" rodata=""

Reviewers: Roger Ferrer, Jonathan Roelofs, Reid Kleckner
Differential Revision: https://reviews.llvm.org/D33412

llvm-svn: 304705

1 files changed, 7 insertions, 0 deletions

diff --git a/clang/lib/CodeGen/CGDecl.cpp b/clang/lib/CodeGen/CGDecl.cpp
index d6abfa15e54..87bfa507a8c 100644
--- a/clang/lib/CodeGen/CGDecl.cpp
+++ b/clang/lib/CodeGen/CGDecl.cpp
@@ -406,6 +406,13 @@ void CodeGenFunction::EmitStaticVarDecl(const VarDecl &D,
   if (D.hasAttr<AnnotateAttr>())
     CGM.AddGlobalAnnotations(&D, var);
 
+  if (auto *SA = D.getAttr<PragmaClangBSSSectionAttr>())
+    var->addAttribute("bss-section", SA->getName());
+  if (auto *SA = D.getAttr<PragmaClangDataSectionAttr>())
+    var->addAttribute("data-section", SA->getName());
+  if (auto *SA = D.getAttr<PragmaClangRodataSectionAttr>())
+    var->addAttribute("rodata-section", SA->getName());
+
   if (const SectionAttr *SA = D.getAttr<SectionAttr>())
     var->setSection(SA->getName());