Teach the MC to output code/data region marker labels in MachO and ELF modes. These are used by disassemblers to provide better disassembly, particularly on targets like ARM Thumb that like to intermingle data in the TEXT segment.

llvm-svn: 141135

1 files changed, 86 insertions, 1 deletions

diff --git a/llvm/lib/MC/MCStreamer.cpp b/llvm/lib/MC/MCStreamer.cpp
index 0fbf3875f1a..3afa22b0d0b 100644
--- a/llvm/lib/MC/MCStreamer.cpp
+++ b/llvm/lib/MC/MCStreamer.cpp
@@ -16,6 +16,7 @@
 #include "llvm/Support/ErrorHandling.h"
 #include "llvm/Support/raw_ostream.h"
 #include "llvm/ADT/SmallString.h"
+#include "llvm/ADT/StringExtras.h"
 #include "llvm/ADT/Twine.h"
 #include <cstdlib>
 using namespace llvm;
@@ -23,7 +24,9 @@ using namespace llvm;
 MCStreamer::MCStreamer(MCContext &Ctx) : Context(Ctx), EmitEHFrame(true),
                                          EmitDebugFrame(false),
                                          CurrentW64UnwindInfo(0),
-                                         LastSymbol(0) {
+                                         LastSymbol(0),
+                                         UniqueCodeBeginSuffix(0),
+                                         UniqueDataBeginSuffix(0) {
   const MCSection *section = NULL;
   SectionStack.push_back(std::make_pair(section, section));
 }
@@ -175,6 +178,87 @@ void MCStreamer::EmitLabel(MCSymbol *Symbol) {
   LastSymbol = Symbol;
 }
 
+void MCStreamer::EmitDataRegion() {
+  if (RegionIndicator == Data) return;
+
+  MCContext &Context = getContext();
+  const MCAsmInfo &MAI = Context.getAsmInfo();
+  if (!MAI.getSupportsDataRegions()) return;
+
+  // Generate a unique symbol name.
+  MCSymbol *NewSym = Context.GetOrCreateSymbol(
+      Twine(MAI.getDataBeginLabelName()) +
+        utostr(UniqueDataBeginSuffix++));
+  EmitLabel(NewSym);
+
+  RegionIndicator = Data;
+}
+
+void MCStreamer::EmitCodeRegion() {
+  if (RegionIndicator == Code) return;
+
+  MCContext &Context = getContext();
+  const MCAsmInfo &MAI = Context.getAsmInfo();
+  if (!MAI.getSupportsDataRegions()) return;
+
+  // Generate a unique symbol name.
+  MCSymbol *NewSym = Context.GetOrCreateSymbol(
+      Twine(MAI.getCodeBeginLabelName()) +
+        utostr(UniqueCodeBeginSuffix++));
+  EmitLabel(NewSym);
+
+  RegionIndicator = Code;
+}
+
+void MCStreamer::EmitJumpTable8Region() {
+  if (RegionIndicator == JumpTable8) return;
+
+  MCContext &Context = getContext();
+  const MCAsmInfo &MAI = Context.getAsmInfo();
+  if (!MAI.getSupportsDataRegions()) return;
+
+  // Generate a unique symbol name.
+  MCSymbol *NewSym = Context.GetOrCreateSymbol(
+      Twine(MAI.getJumpTable8BeginLabelName()) +
+        utostr(UniqueDataBeginSuffix++));
+  EmitLabel(NewSym);
+
+  RegionIndicator = JumpTable8;
+}
+
+void MCStreamer::EmitJumpTable16Region() {
+  if (RegionIndicator == JumpTable16) return;
+
+  MCContext &Context = getContext();
+  const MCAsmInfo &MAI = Context.getAsmInfo();
+  if (!MAI.getSupportsDataRegions()) return;
+
+  // Generate a unique symbol name.
+  MCSymbol *NewSym = Context.GetOrCreateSymbol(
+      Twine(MAI.getJumpTable16BeginLabelName()) +
+        utostr(UniqueDataBeginSuffix++));
+  EmitLabel(NewSym);
+
+  RegionIndicator = JumpTable16;
+}
+
+
+void MCStreamer::EmitJumpTable32Region() {
+  if (RegionIndicator == JumpTable32) return;
+
+  MCContext &Context = getContext();
+  const MCAsmInfo &MAI = Context.getAsmInfo();
+  if (!MAI.getSupportsDataRegions()) return;
+
+  // Generate a unique symbol name.
+  MCSymbol *NewSym = Context.GetOrCreateSymbol(
+      Twine(MAI.getJumpTable32BeginLabelName()) +
+        utostr(UniqueDataBeginSuffix++));
+  EmitLabel(NewSym);
+
+  RegionIndicator = JumpTable32;
+}
+
 void MCStreamer::EmitCompactUnwindEncoding(uint32_t CompactUnwindEncoding) {
   EnsureValidFrame();
   MCDwarfFrameInfo *CurFrame = getCurrentFrameInfo();
@@ -206,6 +290,7 @@ void MCStreamer::EmitCFIStartProc() {
   }
 
   FrameInfos.push_back(Frame);
+  RegionIndicator = Code;
 }
 
 void MCStreamer::EmitCFIEndProc() {