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

1 files changed, 43 insertions, 1 deletions

diff --git a/lib/MC/MCMachOStreamer.cpp b/lib/MC/MCMachOStreamer.cpp
index bc6cf77..970aa8b 100644
--- a/lib/MC/MCMachOStreamer.cpp
+++ b/lib/MC/MCMachOStreamer.cpp
@@ -1,4 +1,3 @@
-//===- lib/MC/MCMachOStreamer.cpp - Mach-O Object Output ------------===//
 //
 //                     The LLVM Compiler Infrastructure
 //
@@ -33,6 +32,8 @@ class MCMachOStreamer : public MCObjectStreamer {
 private:
   virtual void EmitInstToData(const MCInst &Inst);
 
+  void EmitDataRegion(DataRegionData::KindTy Kind);
+  void EmitDataRegionEnd();
 public:
   MCMachOStreamer(MCContext &Context, MCAsmBackend &MAB,
                   raw_ostream &OS, MCCodeEmitter *Emitter)
@@ -46,6 +47,7 @@ public:
   virtual void EmitEHSymAttributes(const MCSymbol *Symbol,
                                    MCSymbol *EHSymbol);
   virtual void EmitAssemblerFlag(MCAssemblerFlag Flag);
+  virtual void EmitDataRegion(MCDataRegionType Kind);
   virtual void EmitThumbFunc(MCSymbol *Func);
   virtual void EmitAssignment(MCSymbol *Symbol, const MCExpr *Value);
   virtual void EmitSymbolAttribute(MCSymbol *Symbol, MCSymbolAttr Attribute);
@@ -138,6 +140,26 @@ void MCMachOStreamer::EmitLabel(MCSymbol *Symbol) {
   SD.setFlags(SD.getFlags() & ~SF_ReferenceTypeMask);
 }
 
+void MCMachOStreamer::EmitDataRegion(DataRegionData::KindTy Kind) {
+  // Create a temporary label to mark the start of the data region.
+  MCSymbol *Start = getContext().CreateTempSymbol();
+  EmitLabel(Start);
+  // Record the region for the object writer to use.
+  DataRegionData Data = { Kind, Start, NULL };
+  std::vector<DataRegionData> &Regions = getAssembler().getDataRegions();
+  Regions.push_back(Data);
+}
+
+void MCMachOStreamer::EmitDataRegionEnd() {
+  std::vector<DataRegionData> &Regions = getAssembler().getDataRegions();
+  assert(Regions.size() && "Mismatched .end_data_region!");
+  DataRegionData &Data = Regions.back();
+  assert(Data.End == NULL && "Mismatched .end_data_region!");
+  // Create a temporary label to mark the end of the data region.
+  Data.End = getContext().CreateTempSymbol();
+  EmitLabel(Data.End);
+}
+
 void MCMachOStreamer::EmitAssemblerFlag(MCAssemblerFlag Flag) {
   // Let the target do whatever target specific stuff it needs to do.
   getAssembler().getBackend().handleAssemblerFlag(Flag);
@@ -153,6 +175,26 @@ void MCMachOStreamer::EmitAssemblerFlag(MCAssemblerFlag Flag) {
   }
 }
 
+void MCMachOStreamer::EmitDataRegion(MCDataRegionType Kind) {
+  switch (Kind) {
+  case MCDR_DataRegion:
+    EmitDataRegion(DataRegionData::Data);
+    return;
+  case MCDR_DataRegionJT8:
+    EmitDataRegion(DataRegionData::JumpTable8);
+    return;
+  case MCDR_DataRegionJT16:
+    EmitDataRegion(DataRegionData::JumpTable16);
+    return;
+  case MCDR_DataRegionJT32:
+    EmitDataRegion(DataRegionData::JumpTable32);
+    return;
+  case MCDR_DataRegionEnd:
+    EmitDataRegionEnd();
+    return;
+  }
+}
+
 void MCMachOStreamer::EmitThumbFunc(MCSymbol *Symbol) {
   // Remember that the function is a thumb function. Fixup and relocation
   // values will need adjusted.