[llvm] r272705 - AMDGPU/SI: Refactor fixup handling for constant addrspace variables

Tom Stellard via llvm-commits llvm-commits at lists.llvm.org
Tue Jun 14 13:30:00 PDT 2016


Author: tstellar
Date: Tue Jun 14 15:29:59 2016
New Revision: 272705

URL: http://llvm.org/viewvc/llvm-project?rev=272705&view=rev
Log:
AMDGPU/SI: Refactor fixup handling for constant addrspace variables

Summary:
We now use a standard fixup type applying the pc-relative address of
constant address space variables, and we have the GlobalAddress lowering
code add the required 4 byte offset to the global address rather than
doing it as part of the fixup.

This refactoring will make it easier to use the same code for global
address space variables and also simplifies the code.

Re-commit this after fixing a bug where we were trying to use a
reference to a Triple object that had already been destroyed.

Reviewers: arsenm, kzhuravl

Subscribers: arsenm, kzhuravl, llvm-commits

Differential Revision: http://reviews.llvm.org/D21154

Modified:
    llvm/trunk/lib/Target/AMDGPU/AMDGPUISelLowering.cpp
    llvm/trunk/lib/Target/AMDGPU/AMDGPUISelLowering.h
    llvm/trunk/lib/Target/AMDGPU/AMDGPUMCInstLower.cpp
    llvm/trunk/lib/Target/AMDGPU/MCTargetDesc/AMDGPUAsmBackend.cpp
    llvm/trunk/lib/Target/AMDGPU/MCTargetDesc/AMDGPUELFObjectWriter.cpp
    llvm/trunk/lib/Target/AMDGPU/MCTargetDesc/AMDGPUFixupKinds.h
    llvm/trunk/lib/Target/AMDGPU/MCTargetDesc/AMDGPUMCTargetDesc.h
    llvm/trunk/lib/Target/AMDGPU/MCTargetDesc/SIMCCodeEmitter.cpp
    llvm/trunk/lib/Target/AMDGPU/SIISelLowering.cpp
    llvm/trunk/lib/Target/AMDGPU/SIISelLowering.h
    llvm/trunk/lib/Target/AMDGPU/SIInstrInfo.cpp
    llvm/trunk/lib/Target/AMDGPU/SIInstrInfo.td
    llvm/trunk/lib/Target/AMDGPU/SIInstructions.td

Modified: llvm/trunk/lib/Target/AMDGPU/AMDGPUISelLowering.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Target/AMDGPU/AMDGPUISelLowering.cpp?rev=272705&r1=272704&r2=272705&view=diff
==============================================================================
--- llvm/trunk/lib/Target/AMDGPU/AMDGPUISelLowering.cpp (original)
+++ llvm/trunk/lib/Target/AMDGPU/AMDGPUISelLowering.cpp Tue Jun 14 15:29:59 2016
@@ -2779,6 +2779,7 @@ const char* AMDGPUTargetLowering::getTar
   NODE_NAME_CASE(CVT_F32_UBYTE3)
   NODE_NAME_CASE(BUILD_VERTICAL_VECTOR)
   NODE_NAME_CASE(CONST_DATA_PTR)
+  NODE_NAME_CASE(PC_ADD_REL_OFFSET)
   case AMDGPUISD::FIRST_MEM_OPCODE_NUMBER: break;
   NODE_NAME_CASE(SENDMSG)
   NODE_NAME_CASE(INTERP_MOV)

Modified: llvm/trunk/lib/Target/AMDGPU/AMDGPUISelLowering.h
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Target/AMDGPU/AMDGPUISelLowering.h?rev=272705&r1=272704&r2=272705&view=diff
==============================================================================
--- llvm/trunk/lib/Target/AMDGPU/AMDGPUISelLowering.h (original)
+++ llvm/trunk/lib/Target/AMDGPU/AMDGPUISelLowering.h Tue Jun 14 15:29:59 2016
@@ -297,6 +297,7 @@ enum NodeType : unsigned {
   INTERP_MOV,
   INTERP_P1,
   INTERP_P2,
+  PC_ADD_REL_OFFSET,
   FIRST_MEM_OPCODE_NUMBER = ISD::FIRST_TARGET_MEMORY_OPCODE,
   STORE_MSKOR,
   LOAD_CONSTANT,

Modified: llvm/trunk/lib/Target/AMDGPU/AMDGPUMCInstLower.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Target/AMDGPU/AMDGPUMCInstLower.cpp?rev=272705&r1=272704&r2=272705&view=diff
==============================================================================
--- llvm/trunk/lib/Target/AMDGPU/AMDGPUMCInstLower.cpp (original)
+++ llvm/trunk/lib/Target/AMDGPU/AMDGPUMCInstLower.cpp Tue Jun 14 15:29:59 2016
@@ -70,7 +70,10 @@ void AMDGPUMCInstLower::lower(const Mach
     case MachineOperand::MO_GlobalAddress: {
       const GlobalValue *GV = MO.getGlobal();
       MCSymbol *Sym = Ctx.getOrCreateSymbol(StringRef(GV->getName()));
-      MCOp = MCOperand::createExpr(MCSymbolRefExpr::create(Sym, Ctx));
+      const MCExpr *SymExpr = MCSymbolRefExpr::create(Sym, Ctx);
+      const MCExpr *Expr = MCBinaryExpr::createAdd(SymExpr,
+          MCConstantExpr::create(MO.getOffset(), Ctx), Ctx);
+      MCOp = MCOperand::createExpr(Expr);
       break;
     }
     case MachineOperand::MO_ExternalSymbol: {

Modified: llvm/trunk/lib/Target/AMDGPU/MCTargetDesc/AMDGPUAsmBackend.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Target/AMDGPU/MCTargetDesc/AMDGPUAsmBackend.cpp?rev=272705&r1=272704&r2=272705&view=diff
==============================================================================
--- llvm/trunk/lib/Target/AMDGPU/MCTargetDesc/AMDGPUAsmBackend.cpp (original)
+++ llvm/trunk/lib/Target/AMDGPU/MCTargetDesc/AMDGPUAsmBackend.cpp Tue Jun 14 15:29:59 2016
@@ -81,6 +81,7 @@ static unsigned getFixupKindNumBytes(uns
     return 2;
   case FK_SecRel_4:
   case FK_Data_4:
+  case FK_PCRel_4:
     return 4;
   case FK_SecRel_8:
   case FK_Data_8:
@@ -105,27 +106,6 @@ void AMDGPUAsmBackend::applyFixup(const
       break;
     }
 
-    case AMDGPU::fixup_si_rodata: {
-      uint32_t *Dst = (uint32_t*)(Data + Fixup.getOffset());
-      // We emit constant data at the end of the text section and generate its
-      // address using the following code sequence:
-      // s_getpc_b64 s[0:1]
-      // s_add_u32 s0, s0, $symbol
-      // s_addc_u32 s1, s1, 0
-      //
-      // s_getpc_b64 returns the address of the s_add_u32 instruction and then
-      // the fixup replaces $symbol with a literal constant, which is a
-      // pc-relative  offset from the encoding of the $symbol operand to the
-      // constant data.
-      //
-      // What we want here is an offset from the start of the s_add_u32
-      // instruction to the constant data, but since the encoding of $symbol
-      // starts 4 bytes after the start of the add instruction, we end up
-      // with an offset that is 4 bytes too small.  This requires us to
-      // add 4 to the fixup value before applying it.
-      *Dst = Value + 4;
-      break;
-    }
     default: {
       // FIXME: Copied from AArch64
       unsigned NumBytes = getFixupKindNumBytes(Fixup.getKind());
@@ -152,7 +132,6 @@ const MCFixupKindInfo &AMDGPUAsmBackend:
   const static MCFixupKindInfo Infos[AMDGPU::NumTargetFixupKinds] = {
     // name                   offset bits  flags
     { "fixup_si_sopp_br",     0,     16,   MCFixupKindInfo::FKF_IsPCRel },
-    { "fixup_si_rodata",      0,     32,   MCFixupKindInfo::FKF_IsPCRel }
   };
 
   if (Kind < FirstTargetFixupKind)
@@ -175,13 +154,15 @@ namespace {
 
 class ELFAMDGPUAsmBackend : public AMDGPUAsmBackend {
   bool Is64Bit;
+  bool HasRelocationAddend;
 
 public:
-  ELFAMDGPUAsmBackend(const Target &T, bool Is64Bit) :
-      AMDGPUAsmBackend(T), Is64Bit(Is64Bit) { }
+  ELFAMDGPUAsmBackend(const Target &T, const Triple &TT) :
+      AMDGPUAsmBackend(T), Is64Bit(TT.getArch() == Triple::amdgcn),
+      HasRelocationAddend(TT.getOS() == Triple::AMDHSA) { }
 
   MCObjectWriter *createObjectWriter(raw_pwrite_stream &OS) const override {
-    return createAMDGPUELFObjectWriter(Is64Bit, OS);
+    return createAMDGPUELFObjectWriter(Is64Bit, HasRelocationAddend, OS);
   }
 };
 
@@ -191,5 +172,5 @@ MCAsmBackend *llvm::createAMDGPUAsmBacke
                                            const MCRegisterInfo &MRI,
                                            const Triple &TT, StringRef CPU) {
   // Use 64-bit ELF for amdgcn
-  return new ELFAMDGPUAsmBackend(T, TT.getArch() == Triple::amdgcn);
+  return new ELFAMDGPUAsmBackend(T, TT);
 }

Modified: llvm/trunk/lib/Target/AMDGPU/MCTargetDesc/AMDGPUELFObjectWriter.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Target/AMDGPU/MCTargetDesc/AMDGPUELFObjectWriter.cpp?rev=272705&r1=272704&r2=272705&view=diff
==============================================================================
--- llvm/trunk/lib/Target/AMDGPU/MCTargetDesc/AMDGPUELFObjectWriter.cpp (original)
+++ llvm/trunk/lib/Target/AMDGPU/MCTargetDesc/AMDGPUELFObjectWriter.cpp Tue Jun 14 15:29:59 2016
@@ -18,7 +18,7 @@ namespace {
 
 class AMDGPUELFObjectWriter : public MCELFObjectTargetWriter {
 public:
-  AMDGPUELFObjectWriter(bool Is64Bit);
+  AMDGPUELFObjectWriter(bool Is64Bit, bool HasRelocationAddend);
 protected:
   unsigned getRelocType(MCContext &Ctx, const MCValue &Target,
                         const MCFixup &Fixup, bool IsPCRel) const override {
@@ -30,11 +30,18 @@ protected:
 
 } // End anonymous namespace
 
-AMDGPUELFObjectWriter::AMDGPUELFObjectWriter(bool Is64Bit)
-  : MCELFObjectTargetWriter(Is64Bit, ELF::ELFOSABI_AMDGPU_HSA,
-                            ELF::EM_AMDGPU, false) { }
+AMDGPUELFObjectWriter::AMDGPUELFObjectWriter(bool Is64Bit,
+                                             bool HasRelocationAddend)
+  : MCELFObjectTargetWriter(Is64Bit,
+                            ELF::ELFOSABI_AMDGPU_HSA,
+                            ELF::EM_AMDGPU,
+                            HasRelocationAddend) { }
 
-MCObjectWriter *llvm::createAMDGPUELFObjectWriter(bool Is64Bit, raw_pwrite_stream &OS) {
-  MCELFObjectTargetWriter *MOTW = new AMDGPUELFObjectWriter(Is64Bit);
+
+MCObjectWriter *llvm::createAMDGPUELFObjectWriter(bool Is64Bit,
+                                                  bool HasRelocationAddend,
+                                                  raw_pwrite_stream &OS) {
+  MCELFObjectTargetWriter *MOTW =
+      new AMDGPUELFObjectWriter(Is64Bit, HasRelocationAddend);
   return createELFObjectWriter(MOTW, OS, true);
 }

Modified: llvm/trunk/lib/Target/AMDGPU/MCTargetDesc/AMDGPUFixupKinds.h
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Target/AMDGPU/MCTargetDesc/AMDGPUFixupKinds.h?rev=272705&r1=272704&r2=272705&view=diff
==============================================================================
--- llvm/trunk/lib/Target/AMDGPU/MCTargetDesc/AMDGPUFixupKinds.h (original)
+++ llvm/trunk/lib/Target/AMDGPU/MCTargetDesc/AMDGPUFixupKinds.h Tue Jun 14 15:29:59 2016
@@ -18,9 +18,6 @@ enum Fixups {
   /// 16-bit PC relative fixup for SOPP branch instructions.
   fixup_si_sopp_br = FirstTargetFixupKind,
 
-  /// fixup for global addresses with constant initializers
-  fixup_si_rodata,
-
   // Marker
   LastTargetFixupKind,
   NumTargetFixupKinds = LastTargetFixupKind - FirstTargetFixupKind

Modified: llvm/trunk/lib/Target/AMDGPU/MCTargetDesc/AMDGPUMCTargetDesc.h
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Target/AMDGPU/MCTargetDesc/AMDGPUMCTargetDesc.h?rev=272705&r1=272704&r2=272705&view=diff
==============================================================================
--- llvm/trunk/lib/Target/AMDGPU/MCTargetDesc/AMDGPUMCTargetDesc.h (original)
+++ llvm/trunk/lib/Target/AMDGPU/MCTargetDesc/AMDGPUMCTargetDesc.h Tue Jun 14 15:29:59 2016
@@ -47,6 +47,7 @@ MCAsmBackend *createAMDGPUAsmBackend(con
                                      const Triple &TT, StringRef CPU);
 
 MCObjectWriter *createAMDGPUELFObjectWriter(bool Is64Bit,
+                                            bool HasRelocationAddend,
                                             raw_pwrite_stream &OS);
 } // End llvm namespace
 

Modified: llvm/trunk/lib/Target/AMDGPU/MCTargetDesc/SIMCCodeEmitter.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Target/AMDGPU/MCTargetDesc/SIMCCodeEmitter.cpp?rev=272705&r1=272704&r2=272705&view=diff
==============================================================================
--- llvm/trunk/lib/Target/AMDGPU/MCTargetDesc/SIMCCodeEmitter.cpp (original)
+++ llvm/trunk/lib/Target/AMDGPU/MCTargetDesc/SIMCCodeEmitter.cpp Tue Jun 14 15:29:59 2016
@@ -248,14 +248,13 @@ uint64_t SIMCCodeEmitter::getMachineOpVa
     return MRI.getEncodingValue(MO.getReg());
 
   if (MO.isExpr()) {
-    const MCSymbolRefExpr *Expr = cast<MCSymbolRefExpr>(MO.getExpr());
-    const MCSymbol &Sym = Expr->getSymbol();
+    const MCSymbolRefExpr *Expr = dyn_cast<MCSymbolRefExpr>(MO.getExpr());
     MCFixupKind Kind;
-    if (Sym.isExternal())
+    if (Expr && Expr->getSymbol().isExternal())
       Kind = FK_Data_4;
     else
-      Kind = (MCFixupKind)AMDGPU::fixup_si_rodata;
-    Fixups.push_back(MCFixup::create(4, Expr, Kind, MI.getLoc()));
+      Kind = FK_PCRel_4;
+    Fixups.push_back(MCFixup::create(4, MO.getExpr(), Kind, MI.getLoc()));
   }
 
   // Figure out the operand number, needed for isSrcOperand check

Modified: llvm/trunk/lib/Target/AMDGPU/SIISelLowering.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Target/AMDGPU/SIISelLowering.cpp?rev=272705&r1=272704&r2=272705&view=diff
==============================================================================
--- llvm/trunk/lib/Target/AMDGPU/SIISelLowering.cpp (original)
+++ llvm/trunk/lib/Target/AMDGPU/SIISelLowering.cpp Tue Jun 14 15:29:59 2016
@@ -1416,6 +1416,40 @@ SDValue SITargetLowering::lowerADDRSPACE
   return DAG.getUNDEF(ASC->getValueType(0));
 }
 
+SDValue SITargetLowering::LowerGlobalAddress(AMDGPUMachineFunction *MFI,
+                                             SDValue Op,
+                                             SelectionDAG &DAG) const {
+  GlobalAddressSDNode *GSD = cast<GlobalAddressSDNode>(Op);
+
+  if (GSD->getAddressSpace() != AMDGPUAS::CONSTANT_ADDRESS)
+    return AMDGPUTargetLowering::LowerGlobalAddress(MFI, Op, DAG);
+
+  SDLoc DL(GSD);
+  const GlobalValue *GV = GSD->getGlobal();
+  MVT PtrVT = getPointerTy(DAG.getDataLayout(), GSD->getAddressSpace());
+
+  // In order to support pc-relative addressing, the PC_ADD_REL_OFFSET SDNode is
+  // lowered to the following code sequence:
+  // s_getpc_b64 s[0:1]
+  // s_add_u32 s0, s0, $symbol
+  // s_addc_u32 s1, s1, 0
+  //
+  // s_getpc_b64 returns the address of the s_add_u32 instruction and then
+  // a fixup or relocation is emitted to replace $symbol with a literal
+  // constant, which is a pc-relative offset from the encoding of the $symbol
+  // operand to the global variable.
+  //
+  // What we want here is an offset from the value returned by s_getpc
+  // (which is the address of the s_add_u32 instruction) to the global
+  // variable, but since the encoding of $symbol starts 4 bytes after the start
+  // of the s_add_u32 instruction, we end up with an offset that is 4 bytes too
+  // small. This requires us to add 4 to the global variable offset in order to
+  // compute the correct address.
+  SDValue GA = DAG.getTargetGlobalAddress(GV, DL, MVT::i32,
+                                          GSD->getOffset() + 4);
+  return DAG.getNode(AMDGPUISD::PC_ADD_REL_OFFSET, DL, PtrVT, GA);
+}
+
 SDValue SITargetLowering::copyToM0(SelectionDAG &DAG, SDValue Chain,
                                    const SDLoc &DL, SDValue V) const {
   // We can't use S_MOV_B32 directly, because there is no way to specify m0 as

Modified: llvm/trunk/lib/Target/AMDGPU/SIISelLowering.h
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Target/AMDGPU/SIISelLowering.h?rev=272705&r1=272704&r2=272705&view=diff
==============================================================================
--- llvm/trunk/lib/Target/AMDGPU/SIISelLowering.h (original)
+++ llvm/trunk/lib/Target/AMDGPU/SIISelLowering.h Tue Jun 14 15:29:59 2016
@@ -23,7 +23,8 @@ namespace llvm {
 class SITargetLowering final : public AMDGPUTargetLowering {
   SDValue LowerParameter(SelectionDAG &DAG, EVT VT, EVT MemVT, const SDLoc &DL,
                          SDValue Chain, unsigned Offset, bool Signed) const;
-
+  SDValue LowerGlobalAddress(AMDGPUMachineFunction *MFI, SDValue Op,
+                             SelectionDAG &DAG) const override;
   SDValue lowerImplicitZextParam(SelectionDAG &DAG, SDValue Op,
                                  MVT VT, unsigned Offset) const;
 

Modified: llvm/trunk/lib/Target/AMDGPU/SIInstrInfo.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Target/AMDGPU/SIInstrInfo.cpp?rev=272705&r1=272704&r2=272705&view=diff
==============================================================================
--- llvm/trunk/lib/Target/AMDGPU/SIInstrInfo.cpp (original)
+++ llvm/trunk/lib/Target/AMDGPU/SIInstrInfo.cpp Tue Jun 14 15:29:59 2016
@@ -914,7 +914,7 @@ bool SIInstrInfo::expandPostRAPseudo(Mac
     break;
   }
 
-  case AMDGPU::SI_CONSTDATA_PTR: {
+  case AMDGPU::SI_PC_ADD_REL_OFFSET: {
     const SIRegisterInfo *TRI =
         static_cast<const SIRegisterInfo *>(ST.getRegisterInfo());
     MachineFunction &MF = *MBB.getParent();

Modified: llvm/trunk/lib/Target/AMDGPU/SIInstrInfo.td
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Target/AMDGPU/SIInstrInfo.td?rev=272705&r1=272704&r2=272705&view=diff
==============================================================================
--- llvm/trunk/lib/Target/AMDGPU/SIInstrInfo.td (original)
+++ llvm/trunk/lib/Target/AMDGPU/SIInstrInfo.td Tue Jun 14 15:29:59 2016
@@ -137,6 +137,10 @@ def SIsampleb : SDSample<"AMDGPUISD::SAM
 def SIsampled : SDSample<"AMDGPUISD::SAMPLED">;
 def SIsamplel : SDSample<"AMDGPUISD::SAMPLEL">;
 
+def SIpc_add_rel_offset : SDNode<"AMDGPUISD::PC_ADD_REL_OFFSET",
+  SDTypeProfile<1, 1, [SDTCisVT<0, iPTR>, SDTCisSameAs<0,1>]>
+>;
+
 //===----------------------------------------------------------------------===//
 // PatFrags for FLAT instructions
 //===----------------------------------------------------------------------===//
@@ -454,7 +458,7 @@ def sopp_brtarget : Operand<OtherVT> {
   let ParserMatchClass = SoppBrTarget;
 }
 
-def const_ga : Operand<iPTR>;
+def si_ga : Operand<iPTR>;
 
 def InterpSlot : Operand<i32> {
   let PrintMethod = "printInterpSlot";

Modified: llvm/trunk/lib/Target/AMDGPU/SIInstructions.td
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Target/AMDGPU/SIInstructions.td?rev=272705&r1=272704&r2=272705&view=diff
==============================================================================
--- llvm/trunk/lib/Target/AMDGPU/SIInstructions.td (original)
+++ llvm/trunk/lib/Target/AMDGPU/SIInstructions.td Tue Jun 14 15:29:59 2016
@@ -2107,10 +2107,10 @@ defm SI_SPILL_V512 : SI_SPILL_VGPR <VReg
 
 let Defs = [SCC] in {
 
-def SI_CONSTDATA_PTR : InstSI <
+def SI_PC_ADD_REL_OFFSET : InstSI <
   (outs SReg_64:$dst),
-  (ins const_ga:$ptr),
-  "", [(set SReg_64:$dst, (i64 (AMDGPUconstdata_ptr (tglobaladdr:$ptr))))]
+  (ins si_ga:$ptr),
+  "", [(set SReg_64:$dst, (i64 (SIpc_add_rel_offset (tglobaladdr:$ptr))))]
 > {
   let SALU = 1;
 }




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