Add support for stack map generation in the X86 backend.

Originally implemented by Lang Hames.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@193811 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 213 insertions, 0 deletions

diff --git a/lib/CodeGen/StackMaps.cpp b/lib/CodeGen/StackMaps.cpp
new file mode 100644
index 0000000000..ffe46288b9
--- /dev/null
+++ b/lib/CodeGen/StackMaps.cpp
@@ -0,0 +1,213 @@
+//===---------------------------- StackMaps.cpp ---------------------------===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+
+#define DEBUG_TYPE "stackmaps"
+
+#include "llvm/CodeGen/StackMaps.h"
+
+#include "llvm/CodeGen/AsmPrinter.h"
+#include "llvm/CodeGen/MachineInstr.h"
+#include "llvm/MC/MCContext.h"
+#include "llvm/MC/MCExpr.h"
+#include "llvm/MC/MCSectionMachO.h"
+#include "llvm/MC/MCStreamer.h"
+#include "llvm/Support/Debug.h"
+#include "llvm/Support/raw_ostream.h"
+#include "llvm/Target/TargetOpcodes.h"
+#include "llvm/Target/TargetMachine.h"
+#include "llvm/Target/TargetRegisterInfo.h"
+
+#include <iterator>
+
+using namespace llvm;
+
+void StackMaps::recordStackMap(const MachineInstr &MI, uint32_t ID,
+                               MachineInstr::const_mop_iterator MOI,
+                               MachineInstr::const_mop_iterator MOE) {
+
+  MCContext &OutContext = AP.OutStreamer.getContext();
+  MCSymbol *MILabel = OutContext.CreateTempSymbol();
+  AP.OutStreamer.EmitLabel(MILabel);
+
+  LocationVec CallsiteLocs;
+
+  while (MOI != MOE) {
+    std::pair<Location, MachineInstr::const_mop_iterator> ParseResult =
+      OpParser(MOI, MOE);
+
+    Location &Loc = ParseResult.first;
+
+    // Move large constants into the constant pool.
+    if (Loc.LocType == Location::Constant && (Loc.Offset & ~0xFFFFFFFFULL)) {
+      Loc.LocType = Location::ConstantIndex;
+      Loc.Offset = ConstPool.getConstantIndex(Loc.Offset);
+    }
+
+    CallsiteLocs.push_back(Loc);
+    MOI = ParseResult.second;
+  }
+
+  const MCExpr *CSOffsetExpr = MCBinaryExpr::CreateSub(
+    MCSymbolRefExpr::Create(MILabel, OutContext),
+    MCSymbolRefExpr::Create(AP.CurrentFnSym, OutContext),
+    OutContext);
+
+  CSInfos.push_back(CallsiteInfo(CSOffsetExpr, ID, CallsiteLocs));
+}
+
+/// serializeToStackMapSection conceptually populates the following fields:
+///
+/// uint32 : Reserved (header)
+/// uint32 : NumConstants
+/// int64  : Constants[NumConstants]
+/// uint32 : NumRecords
+/// StkMapRecord[NumRecords] {
+///   uint32 : PatchPoint ID
+///   uint32 : Instruction Offset
+///   uint16 : Reserved (record flags)
+///   uint16 : NumLocations
+///   Location[NumLocations] {
+///     uint8  : Register | Direct | Indirect | Constant | ConstantIndex
+///     uint8  : Reserved (location flags)
+///     uint16 : Dwarf RegNum
+///     int32  : Offset
+///   }
+/// }
+///
+/// Location Encoding, Type, Value:
+///   0x1, Register, Reg                 (value in register)
+///   0x2, Direct, Reg + Offset          (frame index)
+///   0x3, Indirect, [Reg + Offset]      (spilled value)
+///   0x4, Constant, Offset              (small constant)
+///   0x5, ConstIndex, Constants[Offset] (large constant)
+///
+void StackMaps::serializeToStackMapSection() {
+  // Bail out if there's no stack map data.
+  if (CSInfos.empty())
+    return;
+
+  MCContext &OutContext = AP.OutStreamer.getContext();
+  const TargetRegisterInfo *TRI = AP.TM.getRegisterInfo();
+
+  // Create the section.
+  const MCSection *StackMapSection =
+    OutContext.getMachOSection("__LLVM_STACKMAPS", "__llvm_stackmaps", 0,
+                               SectionKind::getMetadata());
+  AP.OutStreamer.SwitchSection(StackMapSection);
+
+  // Emit a dummy symbol to force section inclusion.
+  AP.OutStreamer.EmitLabel(
+    OutContext.GetOrCreateSymbol(Twine("__LLVM_StackMaps")));
+
+  // Serialize data.
+  const char *WSMP = "Stack Maps: ";
+  const MCRegisterInfo &MCRI = *OutContext.getRegisterInfo();
+
+  DEBUG(dbgs() << "********** Stack Map Output **********\n");
+
+  // Header.
+  AP.OutStreamer.EmitIntValue(0, 4);
+
+  // Num constants.
+  AP.OutStreamer.EmitIntValue(ConstPool.getNumConstants(), 4);
+
+  // Constant pool entries.
+  for (unsigned i = 0; i < ConstPool.getNumConstants(); ++i)
+    AP.OutStreamer.EmitIntValue(ConstPool.getConstant(i), 8);
+
+  DEBUG(dbgs() << WSMP << "#callsites = " << CSInfos.size() << "\n");
+  AP.OutStreamer.EmitIntValue(CSInfos.size(), 4);
+
+  for (CallsiteInfoList::const_iterator CSII = CSInfos.begin(),
+                                        CSIE = CSInfos.end();
+       CSII != CSIE; ++CSII) {
+
+    unsigned CallsiteID = CSII->ID;
+    const LocationVec &CSLocs = CSII->Locations;
+
+    DEBUG(dbgs() << WSMP << "callsite " << CallsiteID << "\n");
+
+    // Verify stack map entry. It's better to communicate a problem to the
+    // runtime than crash in case of in-process compilation. Currently, we do
+    // simple overflow checks, but we may eventually communicate other
+    // compilation errors this way.
+    if (CSLocs.size() > UINT16_MAX) {
+      AP.OutStreamer.EmitIntValue(UINT32_MAX, 4); // Invalid ID.
+      AP.OutStreamer.EmitValue(CSII->CSOffsetExpr, 4);
+      AP.OutStreamer.EmitIntValue(0, 2); // Reserved.
+      AP.OutStreamer.EmitIntValue(0, 2); // 0 locations.
+      continue;
+    }
+
+    AP.OutStreamer.EmitIntValue(CallsiteID, 4);
+    AP.OutStreamer.EmitValue(CSII->CSOffsetExpr, 4);
+
+    // Reserved for flags.
+    AP.OutStreamer.EmitIntValue(0, 2);
+
+    DEBUG(dbgs() << WSMP << "  has " << CSLocs.size() << " locations\n");
+
+    AP.OutStreamer.EmitIntValue(CSLocs.size(), 2);
+
+    unsigned operIdx = 0;
+    for (LocationVec::const_iterator LocI = CSLocs.begin(), LocE = CSLocs.end();
+         LocI != LocE; ++LocI, ++operIdx) {
+      const Location &Loc = *LocI;
+      DEBUG(
+        dbgs() << WSMP << "  Loc " << operIdx << ": ";
+        switch (Loc.LocType) {
+        case Location::Unprocessed:
+          dbgs() << "<Unprocessed operand>";
+          break;
+        case Location::Register:
+          dbgs() << "Register " << MCRI.getName(Loc.Reg);
+          break;
+        case Location::Direct:
+          dbgs() << "Direct " << MCRI.getName(Loc.Reg);
+          if (Loc.Offset)
+            dbgs() << " + " << Loc.Offset;
+          break;
+        case Location::Indirect:
+          dbgs() << "Indirect " << MCRI.getName(Loc.Reg)
+                 << " + " << Loc.Offset;
+          break;
+        case Location::Constant:
+          dbgs() << "Constant " << Loc.Offset;
+          break;
+        case Location::ConstantIndex:
+          dbgs() << "Constant Index " << Loc.Offset;
+          break;
+        }
+        dbgs() << "\n";
+      );
+
+      unsigned RegNo = 0;
+      if(Loc.Reg) {
+        RegNo = MCRI.getDwarfRegNum(Loc.Reg, false);
+        for (MCSuperRegIterator SR(Loc.Reg, TRI);
+             SR.isValid() && (int)RegNo < 0; ++SR) {
+          RegNo = TRI->getDwarfRegNum(*SR, false);
+        }
+      }
+      else {
+        assert((Loc.LocType != Location::Register
+                && Loc.LocType != Location::Register) &&
+               "Missing location register");
+      }
+      AP.OutStreamer.EmitIntValue(Loc.LocType, 1);
+      AP.OutStreamer.EmitIntValue(0, 1); // Reserved location flags.
+      AP.OutStreamer.EmitIntValue(RegNo, 2);
+      AP.OutStreamer.EmitIntValue(Loc.Offset, 4);
+    }
+  }
+
+  AP.OutStreamer.AddBlankLine();
+
+  CSInfos.clear();
+}