[MC][ARM] Delete MCSection::HasData and move SHF_ARM_PURECODE logic to ARMELFObjectWriter::addTargetSectionFlags

This simplifies the generic interface and also makes SHF_ARM_PURECODE
more robust (fixes a TODO). Inspecting MCDataFragment contents covers
more cases than MCObjectStreamer::EmitBytes.

3 files changed, 6 insertions, 10 deletions

diff --git a/llvm/lib/MC/MCObjectStreamer.cpp b/llvm/lib/MC/MCObjectStreamer.cpp
index 5c42667f991..d8a7ab043eb 100644
--- a/llvm/lib/MC/MCObjectStreamer.cpp
+++ b/llvm/lib/MC/MCObjectStreamer.cpp
@@ -569,12 +569,6 @@ void MCObjectStreamer::EmitBytes(StringRef Data) {
   MCDataFragment *DF = getOrCreateDataFragment();
   flushPendingLabels(DF, DF->getContents().size());
   DF->getContents().append(Data.begin(), Data.end());
-
-  // EmitBytes might not cover all possible ways we emit data (or could be used
-  // to emit executable code in some cases), but is the best method we have
-  // right now for checking this.
-  MCSection *Sec = getCurrentSectionOnly();
-  Sec->setHasData(true);
 }
 
 void MCObjectStreamer::EmitValueToAlignment(unsigned ByteAlignment,
diff --git a/llvm/lib/MC/MCSection.cpp b/llvm/lib/MC/MCSection.cpp
index 7a953054e72..074534bd73d 100644
--- a/llvm/lib/MC/MCSection.cpp
+++ b/llvm/lib/MC/MCSection.cpp
@@ -22,8 +22,7 @@ using namespace llvm;
 
 MCSection::MCSection(SectionVariant V, SectionKind K, MCSymbol *Begin)
     : Begin(Begin), BundleGroupBeforeFirstInst(false), HasInstructions(false),
-      HasData(false), IsRegistered(false), DummyFragment(this), Variant(V),
-      Kind(K) {}
+      IsRegistered(false), DummyFragment(this), Variant(V), Kind(K) {}
 
 MCSymbol *MCSection::getEndSymbol(MCContext &Ctx) {
   if (!End)
diff --git a/llvm/lib/Target/ARM/MCTargetDesc/ARMELFObjectWriter.cpp b/llvm/lib/Target/ARM/MCTargetDesc/ARMELFObjectWriter.cpp
index 1fee38821a4..2c26dd388c0 100644
--- a/llvm/lib/Target/ARM/MCTargetDesc/ARMELFObjectWriter.cpp
+++ b/llvm/lib/Target/ARM/MCTargetDesc/ARMELFObjectWriter.cpp
@@ -255,8 +255,11 @@ void ARMELFObjectWriter::addTargetSectionFlags(MCContext &Ctx,
   // execute-only section in the object.
   MCSectionELF *TextSection =
       static_cast<MCSectionELF *>(Ctx.getObjectFileInfo()->getTextSection());
-  if (Sec.getKind().isExecuteOnly() && !TextSection->hasInstructions() &&
-      !TextSection->hasData()) {
+  if (Sec.getKind().isExecuteOnly() && !TextSection->hasInstructions()) {
+    for (auto &F : TextSection->getFragmentList())
+      if (auto *DF = dyn_cast<MCDataFragment>(&F))
+        if (!DF->getContents().empty())
+          return;
     TextSection->setFlags(TextSection->getFlags() | ELF::SHF_ARM_PURECODE);
   }
 }