1 files changed, 160 insertions, 0 deletions
diff --git a/lib/CodeGen/AsmPrinter/OcamlGCPrinter.cpp b/lib/CodeGen/AsmPrinter/OcamlGCPrinter.cpp
new file mode 100644
index 0000000..3531ed6
--- /dev/null
+++ b/lib/CodeGen/AsmPrinter/OcamlGCPrinter.cpp
@@ -0,0 +1,160 @@
+//===-- OcamlGCPrinter.cpp - Ocaml frametable emitter ---------------------===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+//
+// This file implements printing the assembly code for an Ocaml frametable.
+//
+//===----------------------------------------------------------------------===//
+
+#include "llvm/CodeGen/GCs.h"
+#include "llvm/CodeGen/AsmPrinter.h"
+#include "llvm/CodeGen/GCMetadataPrinter.h"
+#include "llvm/Module.h"
+#include "llvm/MC/MCStreamer.h"
+#include "llvm/MC/MCAsmInfo.h"
+#include "llvm/Target/TargetData.h"
+#include "llvm/Target/TargetLoweringObjectFile.h"
+#include "llvm/Target/TargetMachine.h"
+#include "llvm/Support/ErrorHandling.h"
+#include "llvm/Support/FormattedStream.h"
+using namespace llvm;
+
+namespace {
+
+  class OcamlGCMetadataPrinter : public GCMetadataPrinter {
+  public:
+    void beginAssembly(raw_ostream &OS, AsmPrinter &AP,
+                       const MCAsmInfo &MAI);
+
+    void finishAssembly(raw_ostream &OS, AsmPrinter &AP,
+                        const MCAsmInfo &MAI);
+  };
+
+}
+
+static GCMetadataPrinterRegistry::Add<OcamlGCMetadataPrinter>
+Y("ocaml", "ocaml 3.10-compatible collector");
+
+void llvm::linkOcamlGCPrinter() { }
+
+static void EmitCamlGlobal(const Module &M, raw_ostream &OS, AsmPrinter &AP,
+                           const MCAsmInfo &MAI, const char *Id) {
+  const std::string &MId = M.getModuleIdentifier();
+
+  std::string Mangled;
+  Mangled += MAI.getGlobalPrefix();
+  Mangled += "caml";
+  size_t Letter = Mangled.size();
+  Mangled.append(MId.begin(), std::find(MId.begin(), MId.end(), '.'));
+  Mangled += "__";
+  Mangled += Id;
+
+  // Capitalize the first letter of the module name.
+  Mangled[Letter] = toupper(Mangled[Letter]);
+
+  if (const char *GlobalDirective = MAI.getGlobalDirective())
+    OS << GlobalDirective << Mangled << "\n";
+  OS << Mangled << ":\n";
+}
+
+void OcamlGCMetadataPrinter::beginAssembly(raw_ostream &OS, AsmPrinter &AP,
+                                           const MCAsmInfo &MAI) {
+  AP.OutStreamer.SwitchSection(AP.getObjFileLowering().getTextSection());
+  EmitCamlGlobal(getModule(), OS, AP, MAI, "code_begin");
+
+  AP.OutStreamer.SwitchSection(AP.getObjFileLowering().getDataSection());
+  EmitCamlGlobal(getModule(), OS, AP, MAI, "data_begin");
+}
+
+/// emitAssembly - Print the frametable. The ocaml frametable format is thus:
+///
+///   extern "C" struct align(sizeof(intptr_t)) {
+///     uint16_t NumDescriptors;
+///     struct align(sizeof(intptr_t)) {
+///       void *ReturnAddress;
+///       uint16_t FrameSize;
+///       uint16_t NumLiveOffsets;
+///       uint16_t LiveOffsets[NumLiveOffsets];
+///     } Descriptors[NumDescriptors];
+///   } caml${module}__frametable;
+///
+/// Note that this precludes programs from stack frames larger than 64K
+/// (FrameSize and LiveOffsets would overflow). FrameTablePrinter will abort if
+/// either condition is detected in a function which uses the GC.
+///
+void OcamlGCMetadataPrinter::finishAssembly(raw_ostream &OS, AsmPrinter &AP,
+                                            const MCAsmInfo &MAI) {
+  const char *AddressDirective;
+  int AddressAlignLog;
+  if (AP.TM.getTargetData()->getPointerSize() == sizeof(int32_t)) {
+    AddressDirective = MAI.getData32bitsDirective();
+    AddressAlignLog = 2;
+  } else {
+    AddressDirective = MAI.getData64bitsDirective();
+    AddressAlignLog = 3;
+  }
+
+  AP.OutStreamer.SwitchSection(AP.getObjFileLowering().getTextSection());
+  EmitCamlGlobal(getModule(), OS, AP, MAI, "code_end");
+
+  AP.OutStreamer.SwitchSection(AP.getObjFileLowering().getDataSection());
+  EmitCamlGlobal(getModule(), OS, AP, MAI, "data_end");
+
+  OS << AddressDirective << 0 << '\n'; // FIXME: Why does ocaml emit this??
+
+  AP.OutStreamer.SwitchSection(AP.getObjFileLowering().getDataSection());
+  EmitCamlGlobal(getModule(), OS, AP, MAI, "frametable");
+
+  for (iterator I = begin(), IE = end(); I != IE; ++I) {
+    GCFunctionInfo &FI = **I;
+
+    uint64_t FrameSize = FI.getFrameSize();
+    if (FrameSize >= 1<<16) {
+      std::string msg;
+      raw_string_ostream Msg(msg);
+      Msg << "Function '" << FI.getFunction().getName()
+           << "' is too large for the ocaml GC! "
+           << "Frame size " << FrameSize << " >= 65536.\n";
+      Msg << "(" << uintptr_t(&FI) << ")";
+      llvm_report_error(Msg.str()); // Very rude!
+    }
+
+    OS << "\t" << MAI.getCommentString() << " live roots for "
+       << FI.getFunction().getName() << "\n";
+
+    for (GCFunctionInfo::iterator J = FI.begin(), JE = FI.end(); J != JE; ++J) {
+      size_t LiveCount = FI.live_size(J);
+      if (LiveCount >= 1<<16) {
+        std::string msg;
+        raw_string_ostream Msg(msg);
+        Msg << "Function '" << FI.getFunction().getName()
+             << "' is too large for the ocaml GC! "
+             << "Live root count " << LiveCount << " >= 65536.";
+        llvm_report_error(Msg.str()); // Very rude!
+      }
+
+      OS << AddressDirective
+        << MAI.getPrivateGlobalPrefix() << "label" << J->Num << '\n';
+
+      AP.EmitInt16(FrameSize);
+
+      AP.EmitInt16(LiveCount);
+
+      for (GCFunctionInfo::live_iterator K = FI.live_begin(J),
+                                         KE = FI.live_end(J); K != KE; ++K) {
+        assert(K->StackOffset < 1<<16 &&
+               "GC root stack offset is outside of fixed stack frame and out "
+               "of range for ocaml GC!");
+
+        AP.EmitInt32(K->StackOffset);
+      }
+
+      AP.EmitAlignment(AddressAlignLog);
+    }
+  }
+}