Add a GC plugin for Erlang
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@177867 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/CodeGen/AsmPrinter/ErlangGCPrinter.cpp b/lib/CodeGen/AsmPrinter/ErlangGCPrinter.cpp
new file mode 100644
index 0000000..a8fb66d
--- /dev/null
+++ b/lib/CodeGen/AsmPrinter/ErlangGCPrinter.cpp
@@ -0,0 +1,120 @@
+//===-- ErlangGCPrinter.cpp - Erlang/OTP frametable emitter -----*- C++ -*-===//
+//
+// The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+//
+// This file implements the compiler plugin that is used in order to emit
+// garbage collection information in a convenient layout for parsing and
+// loading in the Erlang/OTP runtime.
+//
+//===----------------------------------------------------------------------===//
+
+#include "llvm/CodeGen/AsmPrinter.h"
+#include "llvm/CodeGen/GCs.h"
+#include "llvm/CodeGen/GCMetadataPrinter.h"
+#include "llvm/IR/DataLayout.h"
+#include "llvm/IR/Function.h"
+#include "llvm/IR/Instruction.h"
+#include "llvm/IR/IntrinsicInst.h"
+#include "llvm/IR/Metadata.h"
+#include "llvm/MC/MCAsmInfo.h"
+#include "llvm/MC/MCContext.h"
+#include "llvm/MC/MCSectionELF.h"
+#include "llvm/MC/MCStreamer.h"
+#include "llvm/MC/MCSymbol.h"
+#include "llvm/Target/TargetLoweringObjectFile.h"
+#include "llvm/Target/TargetMachine.h"
+
+using namespace llvm;
+
+namespace {
+
+ class ErlangGCPrinter : public GCMetadataPrinter {
+ public:
+ void beginAssembly(AsmPrinter &AP);
+ void finishAssembly(AsmPrinter &AP);
+ };
+
+}
+
+static GCMetadataPrinterRegistry::Add<ErlangGCPrinter>
+X("erlang", "erlang-compatible garbage collector");
+
+void llvm::linkErlangGCPrinter() { }
+
+void ErlangGCPrinter::beginAssembly(AsmPrinter &AP) { }
+
+void ErlangGCPrinter::finishAssembly(AsmPrinter &AP) {
+ MCStreamer &OS = AP.OutStreamer;
+ unsigned IntPtrSize = AP.TM.getDataLayout()->getPointerSize();
+
+ // Put this in a custom .note section.
+ AP.OutStreamer.SwitchSection(AP.getObjFileLowering().getContext()
+ .getELFSection(".note.gc", ELF::SHT_PROGBITS, 0,
+ SectionKind::getDataRel()));
+
+ // For each function...
+ for (iterator FI = begin(), FE = end(); FI != FE; ++FI) {
+ GCFunctionInfo &MD = **FI;
+
+ /** A compact GC layout. Emit this data structure:
+ *
+ * struct {
+ * int16_t PointCount;
+ * void *SafePointAddress[PointCount];
+ * int16_t StackFrameSize; (in words)
+ * int16_t StackArity;
+ * int16_t LiveCount;
+ * int16_t LiveOffsets[LiveCount];
+ * } __gcmap_<FUNCTIONNAME>;
+ **/
+
+ // Align to address width.
+ AP.EmitAlignment(IntPtrSize == 4 ? 2 : 3);
+
+ // Emit PointCount.
+ OS.AddComment("safe point count");
+ AP.EmitInt16(MD.size());
+
+ // And each safe point...
+ for (GCFunctionInfo::iterator PI = MD.begin(), PE = MD.end(); PI != PE;
+ ++PI) {
+ // Emit the address of the safe point.
+ OS.AddComment("safe point address");
+ MCSymbol *Label = PI->Label;
+ AP.EmitLabelPlusOffset(Label/*Hi*/, 0/*Offset*/, 4/*Size*/);
+ }
+
+ // Stack information never change in safe points! Only print info from the
+ // first call-site.
+ GCFunctionInfo::iterator PI = MD.begin();
+
+ // Emit the stack frame size.
+ OS.AddComment("stack frame size (in words)");
+ AP.EmitInt16(MD.getFrameSize() / IntPtrSize);
+
+ // Emit stack arity, i.e. the number of stacked arguments.
+ unsigned RegisteredArgs = IntPtrSize == 4 ? 5 : 6;
+ unsigned StackArity = MD.getFunction().arg_size() > RegisteredArgs ?
+ MD.getFunction().arg_size() - RegisteredArgs : 0;
+ OS.AddComment("stack arity");
+ AP.EmitInt16(StackArity);
+
+ // Emit the number of live roots in the function.
+ OS.AddComment("live root count");
+ AP.EmitInt16(MD.live_size(PI));
+
+ // And for each live root...
+ for (GCFunctionInfo::live_iterator LI = MD.live_begin(PI),
+ LE = MD.live_end(PI);
+ LI != LE; ++LI) {
+ // Emit live root's offset within the stack frame.
+ OS.AddComment("stack index (offset / wordsize)");
+ AP.EmitInt16(LI->StackOffset / IntPtrSize);
+ }
+ }
+}
diff --git a/lib/CodeGen/ErlangGC.cpp b/lib/CodeGen/ErlangGC.cpp
new file mode 100644
index 0000000..8a1e2d9
--- /dev/null
+++ b/lib/CodeGen/ErlangGC.cpp
@@ -0,0 +1,81 @@
+//===-- ErlangGC.cpp - Erlang/OTP GC strategy -------------------*- C++ -*-===//
+//
+// The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+//
+// This file implements the Erlang/OTP runtime-compatible garbage collector
+// (e.g. defines safe points, root initialization etc.)
+//
+// The frametable emitter is in ErlangGCPrinter.cpp.
+//
+//===----------------------------------------------------------------------===//
+
+#include "llvm/CodeGen/GCs.h"
+#include "llvm/CodeGen/GCStrategy.h"
+#include "llvm/CodeGen/MachineInstrBuilder.h"
+#include "llvm/MC/MCContext.h"
+#include "llvm/MC/MCSymbol.h"
+#include "llvm/Target/TargetInstrInfo.h"
+#include "llvm/Target/TargetMachine.h"
+
+using namespace llvm;
+
+namespace {
+
+ class ErlangGC : public GCStrategy {
+ MCSymbol *InsertLabel(MachineBasicBlock &MBB,
+ MachineBasicBlock::iterator MI,
+ DebugLoc DL) const;
+ public:
+ ErlangGC();
+ bool findCustomSafePoints(GCFunctionInfo &FI, MachineFunction &MF);
+ };
+
+}
+
+static GCRegistry::Add<ErlangGC>
+X("erlang", "erlang-compatible garbage collector");
+
+void llvm::linkErlangGC() { }
+
+ErlangGC::ErlangGC() {
+ InitRoots = false;
+ NeededSafePoints = 1 << GC::PostCall;
+ UsesMetadata = true;
+ CustomRoots = false;
+ CustomSafePoints = true;
+}
+
+MCSymbol *ErlangGC::InsertLabel(MachineBasicBlock &MBB,
+ MachineBasicBlock::iterator MI,
+ DebugLoc DL) const {
+ const TargetInstrInfo* TII = MBB.getParent()->getTarget().getInstrInfo();
+ MCSymbol *Label = MBB.getParent()->getContext().CreateTempSymbol();
+ BuildMI(MBB, MI, DL, TII->get(TargetOpcode::GC_LABEL)).addSym(Label);
+ return Label;
+}
+
+bool ErlangGC::findCustomSafePoints(GCFunctionInfo &FI, MachineFunction &MF) {
+ for (MachineFunction::iterator BBI = MF.begin(), BBE = MF.end(); BBI != BBE;
+ ++BBI)
+ for (MachineBasicBlock::iterator MI = BBI->begin(), ME = BBI->end();
+ MI != ME; ++MI)
+
+ if (MI->getDesc().isCall()) {
+
+ // Do not treat tail call sites as safe points.
+ if (MI->getDesc().isTerminator())
+ continue;
+
+ /* Code copied from VisitCallPoint(...) */
+ MachineBasicBlock::iterator RAI = MI; ++RAI;
+ MCSymbol* Label = InsertLabel(*MI->getParent(), RAI, MI->getDebugLoc());
+ FI.addSafePoint(GC::PostCall, Label, MI->getDebugLoc());
+ }
+
+ return false;
+}