Refactor data-in-code annotations.

Use a dedicated MachO load command to annotate data-in-code regions.
This is the same format the linker produces for final executable images,
allowing consistency of representation and use of introspection tools
for both object and executable files.

Data-in-code regions are annotated via ".data_region"/".end_data_region"
directive pairs, with an optional region type.

data_region_directive := ".data_region" { region_type }
region_type := "jt8" | "jt16" | "jt32" | "jta32"
end_data_region_directive := ".end_data_region"

The previous handling of ARM-style "$d.*" labels was broken and has
been removed. Specifically, it didn't handle ARM vs. Thumb mode when
marking the end of the section.

rdar://11459456

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@157062 91177308-0d34-0410-b5e6-96231b3b80d8

3 files changed, 40 insertions, 22 deletions

diff --git a/lib/Target/ARM/ARMAsmPrinter.cpp b/lib/Target/ARM/ARMAsmPrinter.cpp
index 410790a7ba..e781498f1d 100644
--- a/lib/Target/ARM/ARMAsmPrinter.cpp
+++ b/lib/Target/ARM/ARMAsmPrinter.cpp
@@ -283,9 +283,16 @@ void ARMAsmPrinter::EmitDwarfRegOp(const MachineLocation &MLoc) const {
   }
 }
 
-void ARMAsmPrinter::EmitFunctionEntryLabel() {
-  OutStreamer.ForceCodeRegion();
+void ARMAsmPrinter::EmitFunctionBodyEnd() {
+  // Make sure to terminate any constant pools that were at the end
+  // of the function.
+  if (!InConstantPool)
+    return;
+  InConstantPool = false;
+  OutStreamer.EmitDataRegion(MCDR_DataRegionEnd);
+}
 
+void ARMAsmPrinter::EmitFunctionEntryLabel() {
   if (AFI->isThumbFunction()) {
     OutStreamer.EmitAssemblerFlag(MCAF_Code16);
     OutStreamer.EmitThumbFunc(CurrentFnSym);
@@ -934,13 +941,13 @@ void ARMAsmPrinter::EmitJumpTable(const MachineInstr *MI) {
   const MachineOperand &MO2 = MI->getOperand(OpNum+1); // Unique Id
   unsigned JTI = MO1.getIndex();
 
-  // Tag the jump table appropriately for precise disassembly.
-  OutStreamer.EmitJumpTable32Region();
-
   // Emit a label for the jump table.
   MCSymbol *JTISymbol = GetARMJTIPICJumpTableLabel2(JTI, MO2.getImm());
   OutStreamer.EmitLabel(JTISymbol);
 
+  // Mark the jump table as data-in-code.
+  OutStreamer.EmitDataRegion(MCDR_DataRegionJT32);
+
   // Emit each entry of the table.
   const MachineJumpTableInfo *MJTI = MF->getJumpTableInfo();
   const std::vector<MachineJumpTableEntry> &JT = MJTI->getJumpTables();
@@ -969,6 +976,8 @@ void ARMAsmPrinter::EmitJumpTable(const MachineInstr *MI) {
                                      OutContext);
     OutStreamer.EmitValue(Expr, 4);
   }
+  // Mark the end of jump table data-in-code region.
+  OutStreamer.EmitDataRegion(MCDR_DataRegionEnd);
 }
 
 void ARMAsmPrinter::EmitJump2Table(const MachineInstr *MI) {
@@ -978,15 +987,6 @@ void ARMAsmPrinter::EmitJump2Table(const MachineInstr *MI) {
   const MachineOperand &MO2 = MI->getOperand(OpNum+1); // Unique Id
   unsigned JTI = MO1.getIndex();
 
-  // Emit a label for the jump table.
-  if (MI->getOpcode() == ARM::t2TBB_JT) {
-    OutStreamer.EmitJumpTable8Region();
-  } else if (MI->getOpcode() == ARM::t2TBH_JT) {
-    OutStreamer.EmitJumpTable16Region();
-  } else {
-    OutStreamer.EmitJumpTable32Region();
-  }
-
   MCSymbol *JTISymbol = GetARMJTIPICJumpTableLabel2(JTI, MO2.getImm());
   OutStreamer.EmitLabel(JTISymbol);
 
@@ -995,10 +995,15 @@ void ARMAsmPrinter::EmitJump2Table(const MachineInstr *MI) {
   const std::vector<MachineJumpTableEntry> &JT = MJTI->getJumpTables();
   const std::vector<MachineBasicBlock*> &JTBBs = JT[JTI].MBBs;
   unsigned OffsetWidth = 4;
-  if (MI->getOpcode() == ARM::t2TBB_JT)
+  if (MI->getOpcode() == ARM::t2TBB_JT) {
     OffsetWidth = 1;
-  else if (MI->getOpcode() == ARM::t2TBH_JT)
+    // Mark the jump table as data-in-code.
+    OutStreamer.EmitDataRegion(MCDR_DataRegionJT8);
+  } else if (MI->getOpcode() == ARM::t2TBH_JT) {
     OffsetWidth = 2;
+    // Mark the jump table as data-in-code.
+    OutStreamer.EmitDataRegion(MCDR_DataRegionJT16);
+  }
 
   for (unsigned i = 0, e = JTBBs.size(); i != e; ++i) {
     MachineBasicBlock *MBB = JTBBs[i];
@@ -1031,6 +1036,8 @@ void ARMAsmPrinter::EmitJump2Table(const MachineInstr *MI) {
                                    OutContext);
     OutStreamer.EmitValue(Expr, OffsetWidth);
   }
+  // Mark the end of jump table data-in-code region.
+  OutStreamer.EmitDataRegion(MCDR_DataRegionEnd);
 }
 
 void ARMAsmPrinter::PrintDebugValueComment(const MachineInstr *MI,
@@ -1208,8 +1215,11 @@ extern cl::opt<bool> EnableARMEHABI;
 #include "ARMGenMCPseudoLowering.inc"
 
 void ARMAsmPrinter::EmitInstruction(const MachineInstr *MI) {
-  if (MI->getOpcode() != ARM::CONSTPOOL_ENTRY)
-    OutStreamer.EmitCodeRegion();
+  // If we just ended a constant pool, mark it as such.
+  if (InConstantPool && MI->getOpcode() != ARM::CONSTPOOL_ENTRY) {
+    OutStreamer.EmitDataRegion(MCDR_DataRegionEnd);
+    InConstantPool = false;
+  }
 
   // Emit unwinding stuff for frame-related instructions
   if (EnableARMEHABI && MI->getFlag(MachineInstr::FrameSetup))
@@ -1565,9 +1575,12 @@ void ARMAsmPrinter::EmitInstruction(const MachineInstr *MI) {
     unsigned LabelId = (unsigned)MI->getOperand(0).getImm();
     unsigned CPIdx   = (unsigned)MI->getOperand(1).getIndex();
 
-    // Mark the constant pool entry as data if we're not already in a data
-    // region.
-    OutStreamer.EmitDataRegion();
+    // If this is the first entry of the pool, mark it.
+    if (!InConstantPool) {
+      OutStreamer.EmitDataRegion(MCDR_DataRegion);
+      InConstantPool = true;
+    }
+
     OutStreamer.EmitLabel(GetCPISymbol(LabelId));
 
     const MachineConstantPoolEntry &MCPE = MCP->getConstants()[CPIdx];
diff --git a/lib/Target/ARM/ARMAsmPrinter.h b/lib/Target/ARM/ARMAsmPrinter.h
index af3f75a0e8..3555e8f50a 100644
--- a/lib/Target/ARM/ARMAsmPrinter.h
+++ b/lib/Target/ARM/ARMAsmPrinter.h
@@ -44,9 +44,12 @@ class LLVM_LIBRARY_VISIBILITY ARMAsmPrinter : public AsmPrinter {
   /// MachineFunction.
   const MachineConstantPool *MCP;
 
+  /// InConstantPool - Maintain state when emitting a sequence of constant
+  /// pool entries so we can properly mark them as data regions.
+  bool InConstantPool;
 public:
   explicit ARMAsmPrinter(TargetMachine &TM, MCStreamer &Streamer)
-    : AsmPrinter(TM, Streamer), AFI(NULL), MCP(NULL) {
+    : AsmPrinter(TM, Streamer), AFI(NULL), MCP(NULL), InConstantPool(false) {
       Subtarget = &TM.getSubtarget<ARMSubtarget>();
     }
 
@@ -70,6 +73,7 @@ public:
   bool runOnMachineFunction(MachineFunction &F);
 
   virtual void EmitConstantPool() {} // we emit constant pools customly!
+  virtual void EmitFunctionBodyEnd();
   virtual void EmitFunctionEntryLabel();
   void EmitStartOfAsmFile(Module &M);
   void EmitEndOfAsmFile(Module &M);
diff --git a/lib/Target/ARM/MCTargetDesc/ARMMCAsmInfo.cpp b/lib/Target/ARM/MCTargetDesc/ARMMCAsmInfo.cpp
index 4ac7741ba5..d32805e522 100644
--- a/lib/Target/ARM/MCTargetDesc/ARMMCAsmInfo.cpp
+++ b/lib/Target/ARM/MCTargetDesc/ARMMCAsmInfo.cpp
@@ -29,6 +29,7 @@ ARMMCAsmInfoDarwin::ARMMCAsmInfoDarwin() {
   CommentString = "@";
   Code16Directive = ".code\t16";
   Code32Directive = ".code\t32";
+  UseDataRegionDirectives = true;
 
   SupportsDebugInformation = true;