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, 25 insertions, 0 deletions

diff --git a/clang/lib/Sema/SemaDecl.cpp b/clang/lib/Sema/SemaDecl.cpp
index ef6dfaa2f28..cba220daf77 100644
--- a/clang/lib/Sema/SemaDecl.cpp
+++ b/clang/lib/Sema/SemaDecl.cpp
@@ -8651,6 +8651,14 @@ Sema::ActOnFunctionDeclarator(Scope *S, Declarator &D, DeclContext *DC,
     NewFD->setInvalidDecl();
   }
 
+  // Apply an implicit SectionAttr if '#pragma clang section text' is active
+  if (PragmaClangTextSection.Valid && D.isFunctionDefinition() &&
+      !NewFD->hasAttr<SectionAttr>()) {
+    NewFD->addAttr(PragmaClangTextSectionAttr::CreateImplicit(Context,
+                                                 PragmaClangTextSection.SectionName,
+                                                 PragmaClangTextSection.PragmaLocation));
+  }
+
   // Apply an implicit SectionAttr if #pragma code_seg is active.
   if (CodeSegStack.CurrentValue && D.isFunctionDefinition() &&
       !NewFD->hasAttr<SectionAttr>()) {
@@ -11175,6 +11183,23 @@ void Sema::FinalizeDeclaration(Decl *ThisDecl) {
   if (!VD)
     return;
 
+  // Apply an implicit SectionAttr if '#pragma clang section bss|data|rodata' is active
+  if (VD->hasGlobalStorage() && VD->isThisDeclarationADefinition() &&
+      !inTemplateInstantiation() && !VD->hasAttr<SectionAttr>()) {
+    if (PragmaClangBSSSection.Valid)
+      VD->addAttr(PragmaClangBSSSectionAttr::CreateImplicit(Context,
+                                                            PragmaClangBSSSection.SectionName,
+                                                            PragmaClangBSSSection.PragmaLocation));
+    if (PragmaClangDataSection.Valid)
+      VD->addAttr(PragmaClangDataSectionAttr::CreateImplicit(Context,
+                                                             PragmaClangDataSection.SectionName,
+                                                             PragmaClangDataSection.PragmaLocation));
+    if (PragmaClangRodataSection.Valid)
+      VD->addAttr(PragmaClangRodataSectionAttr::CreateImplicit(Context,
+                                                               PragmaClangRodataSection.SectionName,
+                                                               PragmaClangRodataSection.PragmaLocation));
+  }
+
   if (auto *DD = dyn_cast<DecompositionDecl>(ThisDecl)) {
     for (auto *BD : DD->bindings()) {
       FinalizeDeclaration(BD);