Remove JIT LEGACY_BACKEND code

src/jit/CMakeLists.txt

@@ -64,7 +64,6 @@ set( JIT_SOURCES
   register_arg_convention.cpp
   regset.cpp
   scopeinfo.cpp
-  sharedfloat.cpp
   sideeffects.cpp
   sm.cpp
   smdata.cpp
@@ -95,7 +94,6 @@ if (WIN32)
     block.h
     blockset.h
     codegen.h
-    codegenclassic.h
     codegeninterface.h
     codegenlinear.h
     compiler.h
@@ -120,7 +118,6 @@ if (WIN32)
     emitpub.h
     emitxarch.h
     error.h
-    fp.h
     gentree.h
     gtlist.h
     gtstructs.h
@@ -166,8 +163,6 @@ if (WIN32)
     register.h
     registerarm.h
     registerarm64.h
-    registerfp.h
-    registerxmm.h
     reglist.h
     regpair.h
     regset.h
@@ -196,20 +191,6 @@ if (WIN32)
   )
 endif(WIN32)
 
-# The following defines all the source files used by the "legacy" back-end (#ifdef LEGACY_BACKEND).
-# It is always safe to include both legacy and non-legacy files in the build, as everything is properly
-# #ifdef'ed, though it makes the build slightly slower to do so. Note there is only a legacy backend for
-# x86 and ARM.
-
-set(JIT_ARM_LEGACY_SOURCES
-    codegenlegacy.cpp
-    registerfp.cpp
-)
-set(JIT_I386_LEGACY_SOURCES
-    codegenlegacy.cpp
-    stackfp.cpp
-)
-
 # Define all the architecture-specific source files
 
 set( JIT_AMD64_SOURCES
@@ -226,21 +207,18 @@ set( JIT_AMD64_SOURCES
 )
 
 set( JIT_ARM_SOURCES
-  ${JIT_ARM_LEGACY_SOURCES}
   codegenarmarch.cpp
   codegenarm.cpp
   decomposelongs.cpp
   emitarm.cpp
   lowerarmarch.cpp
-  lowerarm.cpp
   lsraarmarch.cpp
   lsraarm.cpp
   targetarm.cpp
   unwindarm.cpp
 )
 
 set( JIT_I386_SOURCES
-  ${JIT_I386_LEGACY_SOURCES}
   codegenxarch.cpp
   decomposelongs.cpp
   emitxarch.cpp
@@ -259,7 +237,6 @@ set( JIT_ARM64_SOURCES
   codegenarm64.cpp
   emitarm64.cpp
   lowerarmarch.cpp
-  lowerarm64.cpp
   lsraarmarch.cpp
   lsraarm64.cpp
   simd.cpp
@@ -377,11 +354,6 @@ endif (FEATURE_MERGE_JIT_AND_ENGINE)
 
 add_subdirectory(standalone)
 
-if (CLR_CMAKE_TARGET_ARCH_ARM)
-    # Build arm32 legacy_backend to run on both x86 host (crossgen build) and arm host (native).
-    add_subdirectory(legacyjit)
-endif (CLR_CMAKE_TARGET_ARCH_ARM)
-
 if (CLR_CMAKE_PLATFORM_ARCH_I386 OR CLR_CMAKE_PLATFORM_ARCH_AMD64)
     # On x86, build RyuJIT/ARM32 cross-compiling altjit.
     # On amd64, build RyuJIT/ARM64 cross-compiling altjit.
@@ -399,9 +371,3 @@ if ((CLR_CMAKE_PLATFORM_ARCH_I386 OR CLR_CMAKE_PLATFORM_ARCH_AMD64) AND WIN32)
     #   On amd64, build Linux/AMD64 altjit. This enables UNIX_AMD64_ABI.
     add_subdirectory(linuxnonjit)
 endif ()
-
-if (CLR_CMAKE_PLATFORM_ARCH_I386 AND WIN32)
-    # On Windows x86, build altjit generating Windows/ARM32 code using LEGACY_BACKEND.
-    # (Note: we could also create linuxlegacynonjit for generating Linux/ARM32 code using LEGACY_BACKEND, if needed.)
-    add_subdirectory(legacynonjit)
-endif (CLR_CMAKE_PLATFORM_ARCH_I386 AND WIN32)

src/jit/DIRS.proj

@@ -18,21 +18,13 @@
   </PropertyGroup>
 
   <ItemGroup Condition="'$(BuildExePhase)' == '1'">
-    <!-- x86 and ARM clrjit.dll are built in the JIT32 directory; we build FrankenJit here -->
+    <!-- x86 and ARM clrjit.dll are built in the JIT32 directory -->
     <ProjectFile Condition="'$(BuildArchitecture)' != 'i386' and '$(BuildArchitecture)' != 'arm'"  Include="dll\jit.nativeproj" />
   </ItemGroup>
 
   <!-- Only the main JIT gets built for CoreSys. The other jits (e.g., altjits) do not. -->
   <ItemGroup Condition="'$(BuildExePhase)' == '1' and '$(BuildProjectName)' != 'CoreSys'">
 
-    <!-- FrankenJit and FrankenAltJit builds are disabled. We do not test them in CoreCLR and changes from there regularly break legacy_bakend for x86, it is why it is disabled now
-         and should be completely deleted soon. -->
-    <!-- Build the "FrankenJit" (RyuJIT front-end, legacy back-end) and "FrankenAltjit". These can't conflict with the names of the JIT32 directory outputs. -->
-    <!-- 
-    <ProjectFile Condition="'$(BuildArchitecture)' == 'i386' or '$(BuildArchitecture)' == 'arm'"  Include="frankenjit\frankenjit.nativeproj" />
-    <ProjectFile Condition="'$(BuildArchitecture)' == 'i386'" Include="frankenaltjit\frankenaltjit.nativeproj" />
-    -->
-
     <!-- This might be useful, to help make sure JIT devs build all configurations of the JIT (including crossgen), but
          it appears to cause problems with the build system, and it slows down normal JIT developer productivity by adding a seldom-useful build.
     <ProjectFile Include="crossgen\jit_crossgen.nativeproj" />

src/jit/assertionprop.cpp

@@ -4772,9 +4772,6 @@ Compiler::fgWalkResult Compiler::optVNConstantPropCurStmt(BasicBlock* block, Gen
         case GT_RSH:
         case GT_RSZ:
         case GT_NEG:
-#ifdef LEGACY_BACKEND
-        case GT_CHS:
-#endif
         case GT_CAST:
         case GT_INTRINSIC:
             break;

src/jit/block.cpp

@@ -363,17 +363,10 @@ void BasicBlock::dspFlags()
     {
         printf("IBC ");
     }
-#ifdef LEGACY_BACKEND
-    if (bbFlags & BBF_FORWARD_SWITCH)
-    {
-        printf("fswitch ");
-    }
-#else  // !LEGACY_BACKEND
     if (bbFlags & BBF_IS_LIR)
     {
         printf("LIR ");
     }
-#endif // LEGACY_BACKEND
     if (bbFlags & BBF_KEEP_BBJ_ALWAYS)
     {
         printf("KEEP ");
@@ -636,9 +629,6 @@ bool BasicBlock::CloneBlockState(
     to->bbCodeOffs    = from->bbCodeOffs;
     to->bbCodeOffsEnd = from->bbCodeOffsEnd;
     VarSetOps::AssignAllowUninitRhs(compiler, to->bbScope, from->bbScope);
-#if FEATURE_STACK_FP_X87
-    to->bbFPStateX87 = from->bbFPStateX87;
-#endif // FEATURE_STACK_FP_X87
     to->bbNatLoopNum = from->bbNatLoopNum;
 #ifdef DEBUG
     to->bbLoopNum     = from->bbLoopNum;
@@ -663,28 +653,20 @@ bool BasicBlock::CloneBlockState(
 // LIR helpers
 void BasicBlock::MakeLIR(GenTree* firstNode, GenTree* lastNode)
 {
-#ifdef LEGACY_BACKEND
-    unreached();
-#else  // !LEGACY_BACKEND
     assert(!IsLIR());
     assert((firstNode == nullptr) == (lastNode == nullptr));
     assert((firstNode == lastNode) || firstNode->Precedes(lastNode));
 
     m_firstNode = firstNode;
     m_lastNode  = lastNode;
     bbFlags |= BBF_IS_LIR;
-#endif // LEGACY_BACKEND
 }
 
 bool BasicBlock::IsLIR()
 {
-#ifdef LEGACY_BACKEND
-    return false;
-#else  // !LEGACY_BACKEND
     const bool isLIR = (bbFlags & BBF_IS_LIR) != 0;
     assert((bbTreeList == nullptr) || ((isLIR) == !bbTreeList->IsStatement()));
     return isLIR;
-#endif // LEGACY_BACKEND
 }
 
 //------------------------------------------------------------------------
@@ -1311,12 +1293,10 @@ BasicBlock* Compiler::bbNewBasicBlock(BBjumpKinds jumpKind)
         block->bbNum = ++fgBBNumMax;
     }
 
-#ifndef LEGACY_BACKEND
     if (compRationalIRForm)
     {
         block->bbFlags |= BBF_IS_LIR;
     }
-#endif // !LEGACY_BACKEND
 
     block->bbRefs   = 1;
     block->bbWeight = BB_UNITY_WEIGHT;

src/jit/block.h

@@ -77,10 +77,6 @@ struct BasicBlockList;
 struct flowList;
 struct EHblkDsc;
 
-#if FEATURE_STACK_FP_X87
-struct FlatFPStateX87;
-#endif
-
 /*****************************************************************************
  *
  *  The following describes a switch block.
@@ -429,17 +425,7 @@ struct BasicBlock : private LIR::Range
 
 #define BBF_COLD                0x10000000 // BB is cold
 #define BBF_PROF_WEIGHT         0x20000000 // BB weight is computed from profile data
-
-#ifdef LEGACY_BACKEND
-
-#define BBF_FORWARD_SWITCH      0x40000000 // Aux flag used in FP codegen to know if a jmptable entry has been forwarded
-
-#else // !LEGACY_BACKEND
-
 #define BBF_IS_LIR              0x40000000 // Set if the basic block contains LIR (as opposed to HIR)
-
-#endif // LEGACY_BACKEND
-
 #define BBF_KEEP_BBJ_ALWAYS     0x80000000 // A special BBJ_ALWAYS block, used by EH code generation. Keep the jump kind
                                            // as BBJ_ALWAYS. Used for the paired BBJ_ALWAYS block following the
                                            // BBJ_CALLFINALLY block, as well as, on x86, the final step block out of a
@@ -473,14 +459,8 @@ struct BasicBlock : private LIR::Range
 
 // Flags a block should not have had before it is split.
 
-#ifdef LEGACY_BACKEND
-#define BBF_SPLIT_NONEXIST                                                                                             \
-    (BBF_CHANGED | BBF_LOOP_HEAD | BBF_LOOP_CALL0 | BBF_LOOP_CALL1 | BBF_RETLESS_CALL | BBF_LOOP_PREHEADER |           \
-     BBF_COLD | BBF_FORWARD_SWITCH)
-#else // !LEGACY_BACKEND
 #define BBF_SPLIT_NONEXIST                                                                                             \
     (BBF_CHANGED | BBF_LOOP_HEAD | BBF_LOOP_CALL0 | BBF_LOOP_CALL1 | BBF_RETLESS_CALL | BBF_LOOP_PREHEADER | BBF_COLD)
-#endif // LEGACY_BACKEND
 
 // Flags lost by the top block when a block is split.
 // Note, this is a conservative guess.
@@ -999,10 +979,6 @@ struct BasicBlock : private LIR::Range
     verTypeVal* bbTypesOut; // list of variable types on output
 #endif                      // VERIFIER
 
-#if FEATURE_STACK_FP_X87
-    FlatFPStateX87* bbFPStateX87; // State of FP stack on entry to the basic block
-#endif                            // FEATURE_STACK_FP_X87
-
     /* The following fields used for loop detection */
 
     typedef unsigned char loopNumber;

src/jit/codegen.h

@@ -49,7 +49,7 @@ class CodeGen : public CodeGenInterface
                                    bool      nogen = false);
 
 private:
-#if defined(_TARGET_XARCH_) && !FEATURE_STACK_FP_X87
+#if defined(_TARGET_XARCH_)
     // Bit masks used in negating a float or double number.
     // This is to avoid creating more than one data constant for these bitmasks when a
     // method has more than one GT_NEG operation on floating point values.
@@ -68,7 +68,7 @@ class CodeGen : public CodeGenInterface
 
     // Generates SSE41 code for the given tree as a round operation
     void genSSE41RoundOp(GenTreeOp* treeNode);
-#endif // defined(_TARGET_XARCH_) && !FEATURE_STACK_FP_X87
+#endif // defined(_TARGET_XARCH_)
 
     void genPrepForCompiler();
 
@@ -143,16 +143,6 @@ class CodeGen : public CodeGenInterface
     }
 #endif // REG_OPT_RSVD
 
-#ifdef LEGACY_BACKEND
-    regNumber findStkLclInReg(unsigned lclNum)
-    {
-#ifdef DEBUG
-        genInterruptibleUsed = true;
-#endif
-        return regTracker.rsLclIsInReg(lclNum);
-    }
-#endif
-
     //-------------------------------------------------------------------------
 
     bool     genUseBlockInit;  // true if we plan to block-initialize the local stack frame
@@ -199,16 +189,6 @@ class CodeGen : public CodeGenInterface
     void genGenerateStackProbe();
 #endif
 
-#ifdef LEGACY_BACKEND
-    regMaskTP genNewLiveRegMask(GenTree* first, GenTree* second);
-
-    // During codegen, determine the LiveSet after tree.
-    // Preconditions: must be called during codegen, when compCurLife and
-    // compCurLifeTree are being maintained, and tree must occur in the current
-    // statement.
-    VARSET_VALRET_TP genUpdateLiveSetForward(GenTree* tree);
-#endif
-
     //-------------------------------------------------------------------------
 
     void genReportEH();
@@ -260,17 +240,10 @@ class CodeGen : public CodeGenInterface
     void genCodeForBBlist();
 
 public:
-#ifndef LEGACY_BACKEND
-    // genSpillVar is called by compUpdateLifeVar in the !LEGACY_BACKEND case
     void genSpillVar(GenTree* tree);
-#endif // !LEGACY_BACKEND
 
 protected:
-#ifndef LEGACY_BACKEND
     void genEmitHelperCall(unsigned helper, int argSize, emitAttr retSize, regNumber callTarget = REG_NA);
-#else
-    void genEmitHelperCall(unsigned helper, int argSize, emitAttr retSize);
-#endif
 
     void genGCWriteBarrier(GenTree* tgt, GCInfo::WriteBarrierForm wbf);
 
@@ -284,10 +257,6 @@ class CodeGen : public CodeGenInterface
 
     void genExitCode(BasicBlock* block);
 
-#ifdef LEGACY_BACKEND
-    GenTree* genMakeConst(const void* cnsAddr, var_types cnsType, GenTree* cnsTree, bool dblAlign);
-#endif
-
     void genJumpToThrowHlpBlk(emitJumpKind jumpKind, SpecialCodeKind codeKind, GenTree* failBlk = nullptr);
 
     void genCheckOverflow(GenTree* tree);
@@ -417,19 +386,17 @@ class CodeGen : public CodeGenInterface
 
 #endif // _TARGET_AMD64_
 
-#if defined(_TARGET_XARCH_) && !FEATURE_STACK_FP_X87
+#if defined(_TARGET_XARCH_)
 
     // Save/Restore callee saved float regs to stack
     void genPreserveCalleeSavedFltRegs(unsigned lclFrameSize);
     void genRestoreCalleeSavedFltRegs(unsigned lclFrameSize);
     // Generate VZeroupper instruction to avoid AVX/SSE transition penalty
     void genVzeroupperIfNeeded(bool check256bitOnly = true);
 
-#endif // _TARGET_XARCH_ && FEATURE_STACK_FP_X87
+#endif // _TARGET_XARCH_
 
-#if !FEATURE_STACK_FP_X87
     void genZeroInitFltRegs(const regMaskTP& initFltRegs, const regMaskTP& initDblRegs, const regNumber& initReg);
-#endif // !FEATURE_STACK_FP_X87
 
     regNumber genGetZeroReg(regNumber initReg, bool* pInitRegZeroed);
 
@@ -796,11 +763,7 @@ XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX
     unsigned           genTrnslLocalVarCount;
 #endif
 
-#ifndef LEGACY_BACKEND
 #include "codegenlinear.h"
-#else // LEGACY_BACKEND
-#include "codegenclassic.h"
-#endif // LEGACY_BACKEND
 
     /*
     XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX
@@ -819,10 +782,6 @@ XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX
 public:
     void instInit();
 
-#ifdef LEGACY_BACKEND
-    regNumber genGetZeroRegister();
-#endif
-
     void instGen(instruction ins);
 #ifdef _TARGET_XARCH_
     void instNop(unsigned size);