Add support for the --noexecstack option.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@124077 91177308-0d34-0410-b5e6-96231b3b80d8

3 files changed, 26 insertions, 12 deletions

diff --git a/lib/MC/ELFObjectWriter.cpp b/lib/MC/ELFObjectWriter.cpp
index 05dd0c7629..4dbb5387f3 100644
--- a/lib/MC/ELFObjectWriter.cpp
+++ b/lib/MC/ELFObjectWriter.cpp
@@ -329,8 +329,11 @@ namespace {
     virtual void CreateMetadataSections(MCAssembler &Asm, MCAsmLayout &Layout,
                                 const SectionIndexMapTy &SectionIndexMap);
 
-    virtual void CreateGroupSections(MCAssembler &Asm, MCAsmLayout &Layout,
-                             GroupMapTy &GroupMap, RevGroupMapTy &RevGroupMap);
+    // Create the sections that show up in the symbol table. Currently
+    // those are the .note.GNU-stack section and the group sections.
+    virtual void CreateIndexedSections(MCAssembler &Asm, MCAsmLayout &Layout,
+                                       GroupMapTy &GroupMap,
+                                       RevGroupMapTy &RevGroupMap);
 
     virtual void ExecutePostLayoutBinding(MCAssembler &Asm,
                                           const MCAsmLayout &Layout);
@@ -1174,10 +1177,19 @@ ELFObjectWriter::IsSymbolRefDifferenceFullyResolvedImpl(const MCAssembler &Asm,
   return &SecA == &SecB;
 }
 
-void ELFObjectWriter::CreateGroupSections(MCAssembler &Asm,
-                                          MCAsmLayout &Layout,
-                                          GroupMapTy &GroupMap,
-                                          RevGroupMapTy &RevGroupMap) {
+void ELFObjectWriter::CreateIndexedSections(MCAssembler &Asm,
+                                            MCAsmLayout &Layout,
+                                            GroupMapTy &GroupMap,
+                                            RevGroupMapTy &RevGroupMap) {
+  // Create the .note.GNU-stack section if needed.
+  MCContext &Ctx = Asm.getContext();
+  if (Asm.getNoExecStack()) {
+    const MCSectionELF *GnuStackSection =
+      Ctx.getELFSection(".note.GNU-stack", ELF::SHT_PROGBITS, 0,
+                        SectionKind::getReadOnly());
+    Asm.getOrCreateSectionData(*GnuStackSection);
+  }
+
   // Build the groups
   for (MCAssembler::const_iterator it = Asm.begin(), ie = Asm.end();
        it != ie; ++it) {
@@ -1190,7 +1202,7 @@ void ELFObjectWriter::CreateGroupSections(MCAssembler &Asm,
     Asm.getOrCreateSymbolData(*SignatureSymbol);
     const MCSectionELF *&Group = RevGroupMap[SignatureSymbol];
     if (!Group) {
-      Group = Asm.getContext().CreateELFGroupSection();
+      Group = Ctx.CreateELFGroupSection();
       MCSectionData &Data = Asm.getOrCreateSectionData(*Group);
       Data.setAlignment(4);
       MCDataFragment *F = new MCDataFragment(&Data);
@@ -1334,8 +1346,8 @@ void ELFObjectWriter::WriteObject(MCAssembler &Asm,
                                   const MCAsmLayout &Layout) {
   GroupMapTy GroupMap;
   RevGroupMapTy RevGroupMap;
-  CreateGroupSections(Asm, const_cast<MCAsmLayout&>(Layout), GroupMap,
-                      RevGroupMap);
+  CreateIndexedSections(Asm, const_cast<MCAsmLayout&>(Layout), GroupMap,
+                        RevGroupMap);
 
   SectionIndexMapTy SectionIndexMap;
 
diff --git a/lib/MC/MCAssembler.cpp b/lib/MC/MCAssembler.cpp
index 5b291490f7..587068aee5 100644
--- a/lib/MC/MCAssembler.cpp
+++ b/lib/MC/MCAssembler.cpp
@@ -172,7 +172,7 @@ MCAssembler::MCAssembler(MCContext &Context_, TargetAsmBackend &Backend_,
                          MCCodeEmitter &Emitter_, MCObjectWriter &Writer_,
                          raw_ostream &OS_)
   : Context(Context_), Backend(Backend_), Emitter(Emitter_), Writer(Writer_),
-    OS(OS_), RelaxAll(false), SubsectionsViaSymbols(false)
+    OS(OS_), RelaxAll(false), NoExecStack(false), SubsectionsViaSymbols(false)
 {
 }
 
diff --git a/lib/MC/MCELFStreamer.cpp b/lib/MC/MCELFStreamer.cpp
index 6a6c9338ab..ac31057065 100644
--- a/lib/MC/MCELFStreamer.cpp
+++ b/lib/MC/MCELFStreamer.cpp
@@ -515,10 +515,12 @@ void MCELFStreamer::Finish() {
 }
 
 MCStreamer *llvm::createELFStreamer(MCContext &Context, TargetAsmBackend &TAB,
-                                      raw_ostream &OS, MCCodeEmitter *CE,
-                                      bool RelaxAll) {
+                                    raw_ostream &OS, MCCodeEmitter *CE,
+                                    bool RelaxAll, bool NoExecStack) {
   MCELFStreamer *S = new MCELFStreamer(Context, TAB, OS, CE);
   if (RelaxAll)
     S->getAssembler().setRelaxAll(true);
+  if (NoExecStack)
+    S->getAssembler().setNoExecStack(true);
   return S;
 }