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, 30 insertions, 0 deletions

diff --git a/clang/lib/Sema/SemaAttr.cpp b/clang/lib/Sema/SemaAttr.cpp
index 76ca65373dd..8c13ead6445 100644
--- a/clang/lib/Sema/SemaAttr.cpp
+++ b/clang/lib/Sema/SemaAttr.cpp
@@ -126,6 +126,36 @@ void Sema::ActOnPragmaOptionsAlign(PragmaOptionsAlignKind Kind,
   PackStack.Act(PragmaLoc, Action, StringRef(), Alignment);
 }
 
+void Sema::ActOnPragmaClangSection(SourceLocation PragmaLoc, PragmaClangSectionAction Action,
+                                   PragmaClangSectionKind SecKind, StringRef SecName) {
+  PragmaClangSection *CSec;
+  switch (SecKind) {
+    case PragmaClangSectionKind::PCSK_BSS:
+      CSec = &PragmaClangBSSSection;
+      break;
+    case PragmaClangSectionKind::PCSK_Data:
+      CSec = &PragmaClangDataSection;
+      break;
+    case PragmaClangSectionKind::PCSK_Rodata:
+      CSec = &PragmaClangRodataSection;
+      break;
+    case PragmaClangSectionKind::PCSK_Text:
+      CSec = &PragmaClangTextSection;
+      break;
+    default:
+      llvm_unreachable("invalid clang section kind");
+  }
+
+  if (Action == PragmaClangSectionAction::PCSA_Clear) {
+    CSec->Valid = false;
+    return;
+  }
+
+  CSec->Valid = true;
+  CSec->SectionName = SecName;
+  CSec->PragmaLocation = PragmaLoc;
+}
+
 void Sema::ActOnPragmaPack(SourceLocation PragmaLoc, PragmaMsStackAction Action,
                            StringRef SlotLabel, Expr *alignment) {
   Expr *Alignment = static_cast<Expr *>(alignment);