ARM64: unwind data generation. In general, this involved changing the registration

mechanism to more closely align with x64 than ARM32, since x64 has a similar
requirement that unwind data be close (within 4GB) to the code.

New files ARM64UnwindEncoder.cpp/.h provide a generic encoder for ARM64 unwind
xdata, based strictly upon the final codegen. This code is designed to have few
dependencies and be reusable in other contexts.

Future work includes adding support for compact pdata and potentially merging
more of the AMD64 and ARM64 code paths (specifically the xdataallocator).

Author: aaronsgiles

lib/Backend/Chakra.Backend.vcxproj

@@ -145,6 +145,10 @@
       <ExcludedFromBuild Condition="'$(Platform)'!='ARM64'">true</ExcludedFromBuild>
       <ObjectFileName Condition="'$(Platform)'!='ARM64'">$(IntDir)\arm64</ObjectFileName>
     </ClCompile>
+    <ClCompile Include="arm64\ARM64UnwindEncoder.cpp">
+      <ExcludedFromBuild Condition="'$(Platform)'!='ARM64'">true</ExcludedFromBuild>
+      <ObjectFileName Condition="'$(Platform)'!='ARM64'">$(IntDir)\arm64</ObjectFileName>
+    </ClCompile>
     <ClCompile Include="$(MSBuildThisFileDirectory)arm64\EncoderMD.cpp">
       <ExcludedFromBuild Condition="'$(Platform)'!='ARM64'">true</ExcludedFromBuild>
       <!-- Since there are more then one EncoderMD.cpp, we need to set them output into different directory, even when they are ExcludedFromBuild -->
@@ -260,6 +264,9 @@
     <ClInclude Include="arm64\ARM64NeonEncoder.h">
       <ExcludedFromBuild Condition="'$(Platform)'!='ARM64'">true</ExcludedFromBuild>
     </ClInclude>
+    <ClInclude Include="arm64\ARM64UnwindEncoder.h">
+      <ExcludedFromBuild Condition="'$(Platform)'!='ARM64'">true</ExcludedFromBuild>
+    </ClInclude>
     <ClInclude Include="arm64\EncoderMD.h">
       <ExcludedFromBuild Condition="'$(Platform)'!='ARM64'">true</ExcludedFromBuild>
     </ClInclude>
@@ -528,4 +535,4 @@
     <Import Project="$(VCTargetsPath)\BuildCustomizations\masm.targets" />
     <Import Project="$(BuildConfig_ARMASM_Path)armasm.targets" />
   </ImportGroup>
-</Project>
+</Project>

lib/Backend/Chakra.Backend.vcxproj.filters

@@ -147,6 +147,9 @@
     <ClCompile Include="$(MSBuildThisFileDirectory)JITThunkEmitter.cpp" />
     <ClCompile Include="$(MSBuildThisFileDirectory)JavascriptNativeOperators.cpp" />
     <ClCompile Include="$(MSBuildThisFileDirectory)EquivalentTypeSet.cpp" />
+    <ClCompile Include="arm64\ARM64UnwindEncoder.cpp">
+      <Filter>arm64</Filter>
+    </ClCompile>
   </ItemGroup>
   <ItemGroup>
     <ClInclude Include="AgenPeeps.h" />
@@ -374,6 +377,9 @@
     <ClInclude Include="arm64\MdOpCodes.h">
       <Filter>arm64</Filter>
     </ClInclude>
+    <ClInclude Include="arm64\ARM64UnwindEncoder.h">
+      <Filter>arm64</Filter>
+    </ClInclude>
   </ItemGroup>
   <ItemGroup>
     <MASM Include="$(MSBuildThisFileDirectory)amd64\LinearScanMdA.asm">

lib/Backend/Encoder.cpp

@@ -329,7 +329,10 @@ Encoder::Encode()
 #ifdef _M_X64
     pdataCount = 1;
     xdataSize = (ushort)m_func->m_prologEncoder.SizeOfUnwindInfo();
-#elif defined(_M_ARM32_OR_ARM64)
+#elif defined(_M_ARM64)
+    pdataCount = 1;
+    xdataSize = XDATA_SIZE;
+#elif defined(_M_ARM)
 #pragma warning(push)
 #pragma warning(disable:4244) // warning C4244: 'argument': conversion from 'ptrdiff_t' to 'DWORD', possible loss of data
     pdataCount = (ushort)m_func->m_unwindInfo.GetPDataCount(codeSize);
@@ -393,9 +396,13 @@ Encoder::Encode()
     }
 #endif
 
+#ifdef _M_X64_OR_ARM64
 #ifdef _M_X64
-    m_func->m_prologEncoder.FinalizeUnwindInfo(
-        (BYTE*)m_func->GetJITOutput()->GetCodeAddress(), (DWORD)codeSize);
+    PrologEncoder &unwindInfo = m_func->m_prologEncoder;
+#else
+    UnwindInfoManager &unwindInfo = m_func->m_unwindInfo;
+#endif
+    unwindInfo.FinalizeUnwindInfo((BYTE*)m_func->GetJITOutput()->GetCodeAddress(), (DWORD)codeSize);
 
     char * localXdataAddr = nullptr;
 #if ENABLE_OOP_NATIVE_CODEGEN
@@ -414,8 +421,8 @@ Encoder::Encode()
         localXdataAddr = (char*)allocation->xdata.address;
     }
     m_func->GetJITOutput()->RecordUnwindInfo(
-        m_func->m_prologEncoder.GetUnwindInfo(),
-        m_func->m_prologEncoder.SizeOfUnwindInfo(),
+        unwindInfo.GetUnwindInfo(),
+        unwindInfo.SizeOfUnwindInfo(),
         allocation->xdata.address,
         (BYTE*)localXdataAddr);
 #elif _M_ARM
@@ -429,10 +436,9 @@ Encoder::Encode()
     }
     else
     {
-        XDataAllocator::Register(&allocation->xdata, m_func->GetJITOutput()->GetCodeAddress(), m_func->GetJITOutput()->GetCodeSize());
+        XDataAllocator::Register(&allocation->xdata, m_func->GetJITOutput()->GetCodeAddress(), (DWORD)m_func->GetJITOutput()->GetCodeSize());
         m_func->GetInProcJITEntryPointInfo()->SetXDataInfo(&allocation->xdata);
     }
-
     m_func->GetJITOutput()->SetCodeAddress(m_func->GetJITOutput()->GetCodeAddress() | 0x1); // Set thumb mode
 #endif
 

lib/Backend/JITOutput.cpp

@@ -218,7 +218,7 @@ JITOutput::RecordInlineeFrameOffsetsInfo(unsigned int offsetsArrayOffset, unsign
     m_outputData->inlineeFrameOffsetArrayCount = offsetsArrayCount;
 }
 
-#if _M_X64
+#if _M_X64_OR_ARM64
 void
 JITOutput::RecordUnwindInfo(BYTE *unwindInfo, size_t size, BYTE * xdataAddr, BYTE* localXdataAddr)
 {
@@ -229,12 +229,12 @@ JITOutput::RecordUnwindInfo(BYTE *unwindInfo, size_t size, BYTE * xdataAddr, BYT
 
 #elif _M_ARM
 size_t
-JITOutput::RecordUnwindInfo(size_t offset, BYTE *unwindInfo, size_t size, BYTE * xdataAddr)
+JITOutput::RecordUnwindInfo(size_t offset, const BYTE *unwindInfo, size_t size, BYTE * xdataAddr)
 {
     BYTE *xdataFinal = xdataAddr + offset;
 
     Assert(xdataFinal);
-    Assert(((DWORD)xdataFinal & 0x3) == 0); // 4 byte aligned
+    Assert(((ULONG_PTR)xdataFinal & 0x3) == 0); // 4 byte aligned
     memcpy_s(xdataFinal, size, unwindInfo, size);
 
     return (size_t)xdataFinal;

lib/Backend/JITOutput.h

@@ -42,10 +42,10 @@ class JITOutput
     void RecordNativeCode(const BYTE* sourceBuffer, BYTE* localCodeAddress);
     void RecordInlineeFrameOffsetsInfo(unsigned int offsetsArrayOffset, unsigned int offsetsArrayCount);
 
-#if _M_X64
+#if _M_X64_OR_ARM64
     void RecordUnwindInfo(BYTE *unwindInfo, size_t size, BYTE * xdataAddr, BYTE* localXdataAddr);
 #elif _M_ARM
-    size_t RecordUnwindInfo(size_t offset, BYTE *unwindInfo, size_t size, BYTE * xdataAddr);
+    size_t RecordUnwindInfo(size_t offset, const BYTE *unwindInfo, size_t size, BYTE * xdataAddr);
 #endif
 
     void FinalizeNativeCode();

lib/Backend/NativeCodeGenerator.cpp

@@ -1072,7 +1072,7 @@ NativeCodeGenerator::CodeGen(PageAllocator * pageAllocator, CodeGenWorkItem* wor
         workItem->GetEntryPoint()->GetJitTransferData()->SetIsReady();
     }
 
-#if defined(_M_X64)
+#if defined(_M_X64_OR_ARM64)
     XDataAllocation * xdataInfo = HeapNewZ(XDataAllocation);
     xdataInfo->address = (byte*)jitWriteData.xdataAddr;
     XDataAllocator::Register(xdataInfo, jitWriteData.codeAddress, jitWriteData.codeSize);

lib/Backend/Opnd.cpp

@@ -3026,7 +3026,7 @@ Opnd::DumpAddress(void *address, bool printToConsole, bool skipMaskedAddress)
     }
     else
     {
-#ifdef _M_X64
+#ifdef _M_X64_OR_ARM64
         Output::Print(_u("0x%012I64X"), address);
 #else
         Output::Print(_u("0x%08X"), address);

lib/Backend/PDataManager.cpp

@@ -4,7 +4,7 @@
 //-------------------------------------------------------------------------------------------------------
 #include "Backend.h"
 
-// Conditionally-compiled on x64 and arm
+// Conditionally-compiled on x64 and arm/arm64
 #if PDATA_ENABLED
 
 #ifdef _WIN32