Byte code size and serialized byte code size optimizations (15-20% se…

…rialized byte code size reduction)

Byte code size reductions:
- Variable slot index size in layout

Serialized byte code size reductions:
- Move has loopHeaderArray and has asmJsInfo into the bit field (instead of a byte)
- Don't emit field that has non-zero default value.
- Use the defined fields to indicate existing of more field to reduce serialized byte code size
- Use constant type to indicate whether it is property string or not instead of an extra boolean
- Add int8 and int16 constant type for small int encoding in the constant table
- Separate out the byte offset from the character offset in the LineOffsetCache so that we can omit them if the source is purely ASCII-7
    -Reduce by half the memory used by the LineOffsetCache for ASCII-7 sources, and it reduces the serialized byte code size as well.
- Remove unused sourceSpans from byte code serialization.
- Serialize the bit flag with constant encoding (since the bit flag always as a large value)

Also:
- Clean up unused Reg2WithICIndex and REg1Int2 layout
- Move LineOffsetCache to Runtime/Base instead of Common/DataStructures, and de-templatize it as we only use Recycler as the allocator anyway.

lib/Backend/IRBuilder.cpp

@@ -1988,36 +1988,6 @@ IRBuilder::BuildReg2(Js::OpCode newOpcode, uint32 offset, Js::RegSlot R0, Js::Re
     this->AddInstr(instr, offset);
 }
 
-template <typename SizePolicy>
-void
-IRBuilder::BuildReg2WithICIndex(Js::OpCode newOpcode, uint32 offset)
-{
-    AssertMsg(false, "NYI");
-}
-
-template <typename SizePolicy>
-void
-IRBuilder::BuildProfiledReg2WithICIndex(Js::OpCode newOpcode, uint32 offset)
-{
-    Assert(OpCodeAttr::IsProfiledOpWithICIndex(newOpcode));
-    Assert(OpCodeAttr::HasMultiSizeLayout(newOpcode));
-    auto layout = m_jnReader.GetLayout<Js::OpLayoutDynamicProfile<Js::OpLayoutT_Reg2WithICIndex<SizePolicy>>>();
-
-    if (!PHASE_OFF(Js::ClosureRegCheckPhase, m_func))
-    {
-        this->DoClosureRegCheck(layout->R0);
-        this->DoClosureRegCheck(layout->R1);
-    }
-
-    BuildProfiledReg2WithICIndex(newOpcode, offset, layout->R0, layout->R1, layout->profileId, layout->inlineCacheIndex);
-}
-
-void
-IRBuilder::BuildProfiledReg2WithICIndex(Js::OpCode newOpcode, uint32 offset, Js::RegSlot dstRegSlot, Js::RegSlot srcRegSlot, Js::ProfileId profileId, Js::InlineCacheIndex inlineCacheIndex)
-{
-    BuildProfiledReg2(newOpcode, offset, dstRegSlot, srcRegSlot, profileId, inlineCacheIndex);
-}
-
 ///----------------------------------------------------------------------------
 ///
 /// IRBuilder::BuildProfiledReg2
@@ -2043,7 +2013,7 @@ IRBuilder::BuildProfiledReg2(Js::OpCode newOpcode, uint32 offset)
 }
 
 void
-IRBuilder::BuildProfiledReg2(Js::OpCode newOpcode, uint32 offset, Js::RegSlot dstRegSlot, Js::RegSlot srcRegSlot, Js::ProfileId profileId, Js::InlineCacheIndex inlineCacheIndex)
+IRBuilder::BuildProfiledReg2(Js::OpCode newOpcode, uint32 offset, Js::RegSlot dstRegSlot, Js::RegSlot srcRegSlot, Js::ProfileId profileId)
 {
     bool switchFound = false;
 
@@ -2112,7 +2082,6 @@ IRBuilder::BuildProfiledReg2(Js::OpCode newOpcode, uint32 offset, Js::RegSlot ds
         IR::JitProfilingInstr *profiledInstr = IR::JitProfilingInstr::New(newOpcode, dstOpnd, src1Opnd, m_func);
         profiledInstr->profileId = profileId;
         profiledInstr->isBeginSwitch = newOpcode == Js::OpCode::Ld_A;
-        profiledInstr->inlineCacheIndex = inlineCacheIndex;
         instr = profiledInstr;
     }
     else if(isProfiled)
@@ -2834,30 +2803,6 @@ IRBuilder::BuildUnsigned1(Js::OpCode newOpcode, uint32 offset, uint32 num)
     }
 }
 
-void
-IRBuilder::BuildReg1Int2(Js::OpCode newOpcode, uint32 offset)
-{
-    Assert(!OpCodeAttr::HasMultiSizeLayout(newOpcode));
-
-    const unaligned Js::OpLayoutReg1Int2 *regLayout = m_jnReader.Reg1Int2();
-    Js::RegSlot     R0 = regLayout->R0;
-    int32           C1 = regLayout->C1;
-    int32           C2 = regLayout->C2;
-
-    if (!PHASE_OFF(Js::ClosureRegCheckPhase, m_func))
-    {
-        this->DoClosureRegCheck(R0);
-    }
-
-    IR::RegOpnd* dstOpnd = this->BuildDstOpnd(R0);
-
-    IR::IntConstOpnd * srcOpnd = IR::IntConstOpnd::New(C1, TyInt32, m_func);
-    IR::IntConstOpnd * src2Opnd = IR::IntConstOpnd::New(C2, TyInt32, m_func);
-    IR::Instr* instr = IR::Instr::New(newOpcode, dstOpnd, srcOpnd, src2Opnd, m_func);
-
-    this->AddInstr(instr, offset);
-}
-
 template <typename SizePolicy>
 void
 IRBuilder::BuildProfiledReg1Unsigned1(Js::OpCode newOpcode, uint32 offset)

lib/Backend/IRBuilder.h

@@ -130,8 +130,7 @@ class IRBuilder
 
     void                BuildReg1(Js::OpCode newOpcode, uint32 offset, Js::RegSlot R0);
     void                BuildReg2(Js::OpCode newOpcode, uint32 offset, Js::RegSlot R0, Js::RegSlot R1, uint32 nextOffset);
-    void                BuildProfiledReg2(Js::OpCode newOpcode, uint32 offset, Js::RegSlot dstRegSlot, Js::RegSlot srcRegSlot, Js::ProfileId profileId, Js::InlineCacheIndex inlineCacheIndex = Js::Constants::NoInlineCacheIndex);
-    void                BuildProfiledReg2WithICIndex(Js::OpCode newOpcode, uint32 offset, Js::RegSlot dstRegSlot, Js::RegSlot srcRegSlot, Js::ProfileId profileId, Js::InlineCacheIndex inlineCacheIndex);
+    void                BuildProfiledReg2(Js::OpCode newOpcode, uint32 offset, Js::RegSlot dstRegSlot, Js::RegSlot srcRegSlot, Js::ProfileId profileId);
     void                BuildReg3(Js::OpCode newOpcode, uint32 offset, Js::RegSlot dstRegSlot, Js::RegSlot src1RegSlot,
                             Js::RegSlot src2RegSlot, Js::ProfileId profileId);
     void                BuildReg3C(Js::OpCode newOpCode, uint32 offset, Js::RegSlot dstRegSlot, Js::RegSlot src1RegSlot,

lib/Backend/Lower.cpp

@@ -8130,7 +8130,7 @@ Lowerer::LowerUnaryHelperMemWithFuncBody(IR::Instr *instr, IR::JnHelperMethod he
 IR::Instr *
 Lowerer::LowerBinaryHelperMemWithFuncBody(IR::Instr *instr, IR::JnHelperMethod helperMethod)
 {
-    AssertMsg(Js::OpCodeUtil::GetOpCodeLayout(instr->m_opcode) == Js::OpLayoutType::Reg1Int2, "Expected a binary instruction...");
+    AssertMsg(Js::OpCodeUtil::GetOpCodeLayout(instr->m_opcode) == Js::OpLayoutType::Reg3, "Expected a binary instruction...");
 
     m_lowererMD.LoadHelperArgument(instr, this->LoadFunctionBodyOpnd(instr));
     return this->LowerBinaryHelperMem(instr, helperMethod);
@@ -8217,7 +8217,6 @@ Lowerer::LowerBinaryHelper(IR::Instr *instr, IR::JnHelperMethod helperMethod)
     AssertMsg((Js::OpCodeUtil::GetOpCodeLayout(instr->m_opcode) == Js::OpLayoutType::Reg1Unsigned1 && !instr->GetDst()) ||
               Js::OpCodeUtil::GetOpCodeLayout(instr->m_opcode) == Js::OpLayoutType::Reg3 ||
               Js::OpCodeUtil::GetOpCodeLayout(instr->m_opcode) == Js::OpLayoutType::Reg2Int1 ||
-              Js::OpCodeUtil::GetOpCodeLayout(instr->m_opcode) == Js::OpLayoutType::Reg1Int2 ||
               Js::OpCodeUtil::GetOpCodeLayout(instr->m_opcode) == Js::OpLayoutType::ElementU ||
               instr->m_opcode == Js::OpCode::InvalCachedScope, "Expected a binary instruction...");
 
@@ -8241,7 +8240,6 @@ Lowerer::LowerBinaryHelperMem(IR::Instr *instr, IR::JnHelperMethod helperMethod)
 
     AssertMsg(Js::OpCodeUtil::GetOpCodeLayout(instr->m_opcode) == Js::OpLayoutType::Reg3 ||
               Js::OpCodeUtil::GetOpCodeLayout(instr->m_opcode) == Js::OpLayoutType::Reg2Int1 ||
-              Js::OpCodeUtil::GetOpCodeLayout(instr->m_opcode) == Js::OpLayoutType::Reg1Int2 ||
               Js::OpCodeUtil::GetOpCodeLayout(instr->m_opcode) == Js::OpLayoutType::Reg1Unsigned1, "Expected a binary instruction...");
 
     instrPrev = LoadScriptContext(instr);

lib/Common/Common.h

@@ -118,7 +118,6 @@ template<> struct IntMath<int64> { using Type = Int64Math; };
 #include "DataStructures/GrowingArray.h"
 #include "DataStructures/EvalMapString.h"
 #include "DataStructures/RegexKey.h"
-#include "DataStructures/LineOffsetCache.h"
 
 #include "Core/ICustomConfigFlags.h"
 #include "Core/CmdParser.h"

lib/Common/DataStructures/Chakra.Common.DataStructures.vcxproj

@@ -60,7 +60,6 @@
     <ClInclude Include="GrowingArray.h" />
     <ClInclude Include="ImmutableList.h" />
     <ClInclude Include="Interval.h" />
-    <ClInclude Include="LineOffsetCache.h" />
     <ClInclude Include="LeafValueDictionary.h" />
     <ClInclude Include="MruDictionary.h" />
     <ClInclude Include="PageStack.h" />