Implement GC-Table generation

Translate GcInfo from __llvm.stackmaps section to
CoreCLR GCInfo Encoding.

Testing:
1) We can now build and a few tests in a precise-GC environment.
   The correctness of generated GCInfo is verified by:
   a) Examining the GcInfo dump in the debugger (SOS) and comparing
      it against the assembly dump.
   b) Stepping through the debugger and watch it scan through the
      reported GC-Roots.
   c) The execution crashes for the same functions if the liveness
      information is not reported.

2) The execution crashes if we try to build MsCorLib for precise-GC.
There are a few known issues (as noted in the comments) and the
remaining issues need to be fixed via debugging.

3) The standard LLILC testig is still done using conservative-gc
So, no testing impact is expected for the lab. A separate test-leg will
be added to run tests with precise-GC.

include/GcInfo/GcInfo.h

@@ -9,14 +9,44 @@
 //===----------------------------------------------------------------------===//
 ///
 /// \file
-/// \brief Wrapper that includes all GcInfo related headers
+/// \brief GCInfo Generator for LLILC
 ///
 //===----------------------------------------------------------------------===//
 
 #ifndef GCINFO_H
 #define GCINFO_H
 
-#define STANDALONE_BUILD
-#include "gcinfoencoder.h"
+#include "jitpch.h"
+#include "LLILCJit.h"
+
+class GcInfoAllocator;
+class GcInfoEncoder;
+
+/// \brief This is the translator from LLVM's GC StackMaps
+///  to CoreCLR's GcInfo encoding.
+class GCInfo {
+public:
+  /// Construct a GCInfo object
+  /// \param JitContext Context record for the method's jit request.
+  /// \param StackMapData A pointer to the .llvm_stackmaps section
+  ///        loaded in memory
+  /// \param Start address of the Code section block
+  GCInfo(LLILCJitContext *JitContext, uint8_t *LLVMStackMapData,
+         uint8_t *CodeBlockStart);
+
+  /// Emit GC Info to the EE using GcInfoEncoder.
+  void emitGCInfo();
+
+private:
+  void encodeHeader();
+  void encodeLiveness();
+  void emitEncoding();
+
+  LLILCJitContext *JitContext;
+  uint8_t *LLVMStackMapData;
+  GcInfoEncoder *Encoder;
+  uint8_t *CodeBlockStart;
+  bool EmitLogs;
+};
 
 #endif // GCINFO_H

include/GcInfo/GcInfoUtil.h

@@ -503,10 +503,10 @@ class StructArrayListBase {
   };
   friend class ArrayIteratorBase;
 
-  StructArrayListEntryBase *
-      m_pChunkListHead; // actually StructArrayListEntry<ELEMENT_TYPE>*
-  StructArrayListEntryBase *
-      m_pChunkListTail; // actually StructArrayListEntry<ELEMENT_TYPE>*
+  StructArrayListEntryBase
+      *m_pChunkListHead; // actually StructArrayListEntry<ELEMENT_TYPE>*
+  StructArrayListEntryBase
+      *m_pChunkListTail; // actually StructArrayListEntry<ELEMENT_TYPE>*
   SIZE_T m_nItemsInLastChunk;
   SIZE_T m_nTotalItems;
   SIZE_T m_nLastChunkCapacity;

include/GcInfo/Target.h

@@ -0,0 +1,51 @@
+//===---- include/gcinfo/target.h -------------------------------*- C++ -*-===//
+//
+// LLILC
+//
+// Copyright (c) Microsoft. All rights reserved.
+// Licensed under the MIT license.
+// See LICENSE file in the project root for full license information.
+//
+//===----------------------------------------------------------------------===//
+///
+/// \file
+/// \brief Target specific definitions for GCInfo generation
+///
+//===----------------------------------------------------------------------===//
+
+#ifndef GCINFO_TARGET_H
+#define GCINFO_TARGET_H
+
+#include "global.h"
+
+#if (defined(_TARGET_X86_) || defined(_TARGET_X64_) || defined(_TARGET_AMD64_))
+
+// Define DWARF encodings for registers
+// Size variants (ex: AL,AH,AX,EAX,RAX) all get the same Dwarf register number
+
+#define DW_RAX 0
+#define DW_RBX 3
+#define DW_RCX 2
+#define DW_RDX 1
+#define DW_RSI 4
+#define DW_RDI 5
+#define DW_RBP 6
+#define DW_RSP 7
+#define DW_RIP 16
+#define DW_R8 8
+#define DW_R9 9
+#define DW_R10 10
+#define DW_R11 11
+#define DW_R12 12
+#define DW_R13 13
+#define DW_R14 14
+#define DW_R15 15
+
+#define DW_FRAME_POINTER DW_RBP
+#define DW_STACK_POINTER DW_RSP
+
+#else
+#error GCTables not implemented for this target
+#endif // defined(_TARGET_X86_ || _TARGET_X64_ || _TARGET_AMD64_)
+
+#endif // GCINFO_TARGET_H

include/Jit/EEMemoryManager.h

@@ -34,7 +34,7 @@ class EEMemoryManager : public RTDyldMemoryManager {
   /// \param C Jit context for the method being jitted.
   EEMemoryManager(LLILCJitContext *C)
       : Context(C), HotCodeBlock(nullptr), ColdCodeBlock(nullptr),
-        ReadOnlyDataBlock(nullptr) {}
+        ReadOnlyDataBlock(nullptr), StackMapBlock(nullptr) {}
 
   /// Destroy an \p EEMemoryManager
   ~EEMemoryManager() override;
@@ -127,11 +127,26 @@ class EEMemoryManager : public RTDyldMemoryManager {
   void deregisterEHFrames(uint8_t *Addr, uint64_t LoadAddr,
                           size_t Size) override;
 
+  /// \brief Get the LLVM Stackmap section if allocated.
+  ///
+  /// Returns a pointer to the .llvm_stackmaps section
+  /// if it is already loaded into memory.
+
+  uint8_t *getStackMapSection() { return StackMapBlock; }
+
+  /// \brief Get the HotCode section if allocated.
+  ///
+  /// Returns a pointer to the HotCode section
+  /// if it is already loaded into memory.
+
+  uint8_t *getHotCodeBlock() { return HotCodeBlock; }
+
 private:
   LLILCJitContext *Context;         ///< LLVM context for types, etc.
   uint8_t *HotCodeBlock;            ///< Memory to hold the hot method code.
   uint8_t *ColdCodeBlock;           ///< Memory to hold the cold method code.
   uint8_t *ReadOnlyDataBlock;       ///< Memory to hold the readonly data.
+  uint8_t *StackMapBlock;           ///< Memory to hold the readonly StackMap
   uint8_t *ReadOnlyDataUnallocated; ///< Address of unallocated part of RO data.
 };
 } // namespace llvm

include/Jit/LLILCJit.h

@@ -17,7 +17,7 @@
 #define LLILC_JIT_H
 
 #include "Pal/LLILCPal.h"
-#include "options.h"
+#include "Reader/options.h"
 #include "llvm/ExecutionEngine/ExecutionEngine.h"
 #include "llvm/ExecutionEngine/RuntimeDyld.h"
 #include "llvm/IR/LLVMContext.h"
@@ -106,9 +106,10 @@ struct LLILCJitContext {
 
   /// \name Jit output sizes
   //@{
-  uint32_t HotCodeSize = 0;      ///< Size of hot code section in bytes.
-  uint32_t ColdCodeSize = 0;     ///< Size of cold code section in bytes.
-  uint32_t ReadOnlyDataSize = 0; ///< Size of readonly data ref'd from code.
+  uintptr_t HotCodeSize = 0;      ///< Size of hot code section in bytes.
+  uintptr_t ColdCodeSize = 0;     ///< Size of cold code section in bytes.
+  uintptr_t ReadOnlyDataSize = 0; ///< Size of readonly data ref'd from code.
+  uintptr_t StackMapSize = 0;     ///< Size of readonly Stackmap section.
   //@}
 };
 
@@ -236,10 +237,6 @@ class LLILCJit : public ICorJitCompiler {
   /// \returns \p true if the conversion was successful.
   bool readMethod(LLILCJitContext *JitContext);
 
-  /// Output GC info to the EE.
-  /// \param JitContext Context record for the method's jit request.
-  void outputGCInfo(LLILCJitContext *JitContext);
-
 public:
   /// A pointer to the singleton jit instance.
   static LLILCJit *TheJit;

include/Jit/jitoptions.h

@@ -69,9 +69,14 @@ class JitOptions : public Options {
 
   /// \brief Set DoTailCallOpt based on environment variable.
   ///
-  /// \returns true if COMPLUS_TAILCALLOPT is set in the environment set.
+  /// \returns true if COMPLUS_TAILCALLOPT is set in the environment.
   static bool queryDoTailCallOpt(LLILCJitContext &JitContext);
 
+  /// \brief Set LogGcInfo based on environment variable.
+  ///
+  /// \returns true if COMPLUS_JitGCInfoLogging is set in the environment.
+  static bool queryLogGcInfo(LLILCJitContext &JitContext);
+
 public:
   bool IsAltJit; ///< True if running as the alternative JIT.
 

include/Reader/options.h

@@ -53,5 +53,6 @@ struct Options {
   bool UseConservativeGC;   ///< True if the environment is set to use CGC.
   bool DoInsertStatepoints; ///< True if the environment calls for statepoints.
   bool DoTailCallOpt;       ///< Tail call optimization.
+  bool LogGcInfo;           ///< Generate GCInfo Translation logs
 };
 #endif // OPTIONS_H

lib/GcInfo/CMakeLists.txt

@@ -19,4 +19,5 @@ add_llilcjit_library(GcInfo
     STATIC
 	${CORECLR_GCINFO}/gcinfoencoder.cpp
 	GcInfoUtil.cpp
+	GcInfo.cpp
 )