[GlobalISel][X86] Support G_GLOBAL_VALUE operation.

[igorb]

Summary

Support G_GLOBAL_VALUE operation. For now most of the PIC configurations not implemented yet.

[guyblank]

LGTM

llvm/trunk/lib/Target/X86/X86InstructionSelector.cpp

private:
   // TODO: remove after supported by Tablegen-erated instruction selection.
   unsigned getLoadStoreOp(LLT &Ty, const RegisterBank &RB, unsigned Opc,
                           uint64_t Alignment) const;
 
   bool selectLoadStoreOp(MachineInstr &I, MachineRegisterInfo &MRI,
                          MachineFunction &MF) const;
   bool selectFrameIndexOrGep(MachineInstr &I, MachineRegisterInfo &MRI,
                              MachineFunction &MF) const;
+  bool selectGlobalValue(MachineInstr &I, MachineRegisterInfo &MRI,
+                         MachineFunction &MF) const;
   bool selectConstant(MachineInstr &I, MachineRegisterInfo &MRI,
                       MachineFunction &MF) const;
   bool selectTrunc(MachineInstr &I, MachineRegisterInfo &MRI,
                    MachineFunction &MF) const;
   bool selectZext(MachineInstr &I, MachineRegisterInfo &MRI,
                   MachineFunction &MF) const;
   bool selectCmp(MachineInstr &I, MachineRegisterInfo &MRI,
                  MachineFunction &MF) const;
bool X86InstructionSelector::select(MachineInstr &I) const {
 
   DEBUG(dbgs() << " C++ instruction selection: "; I.print(dbgs()));
 
   // TODO: This should be implemented by tblgen.
   if (selectLoadStoreOp(I, MRI, MF))
     return true;
   if (selectFrameIndexOrGep(I, MRI, MF))
     return true;
+  if (selectGlobalValue(I, MRI, MF))
+    return true;
   if (selectConstant(I, MRI, MF))
     return true;
   if (selectTrunc(I, MRI, MF))
     return true;
   if (selectZext(I, MRI, MF))
     return true;
   if (selectCmp(I, MRI, MF))
     return true;
if (Opc == TargetOpcode::G_LOAD) {
     // G_STORE (VAL, Addr), X86Store instruction (Addr, VAL)
     I.RemoveOperand(1);
     I.RemoveOperand(0);
     addFullAddress(MIB, AM).addUse(DefReg);
   }
   return constrainSelectedInstRegOperands(I, TII, TRI, RBI);
 }
 
+static unsigned getLeaOP(LLT Ty, const X86Subtarget &STI) {
+  if (Ty == LLT::pointer(0, 64))
+    return X86::LEA64r;
+  else if (Ty == LLT::pointer(0, 32))
+    return STI.isTarget64BitILP32() ? X86::LEA64_32r : X86::LEA32r;
+  else
+    llvm_unreachable("Can't get LEA opcode. Unsupported type.");
+}
+
 bool X86InstructionSelector::selectFrameIndexOrGep(MachineInstr &I,
                                                    MachineRegisterInfo &MRI,
                                                    MachineFunction &MF) const {
   unsigned Opc = I.getOpcode();
 
   if (Opc != TargetOpcode::G_FRAME_INDEX && Opc != TargetOpcode::G_GEP)
     return false;
 
   const unsigned DefReg = I.getOperand(0).getReg();
   LLT Ty = MRI.getType(DefReg);
 
   // Use LEA to calculate frame index and GEP
-  unsigned NewOpc;
-  if (Ty == LLT::pointer(0, 64))
-    NewOpc = X86::LEA64r;
-  else if (Ty == LLT::pointer(0, 32))
-    NewOpc = STI.isTarget64BitILP32() ? X86::LEA64_32r : X86::LEA32r;
-  else
-    llvm_unreachable("Can't select G_FRAME_INDEX/G_GEP, unsupported type.");
-
+  unsigned NewOpc = getLeaOP(Ty, STI);
   I.setDesc(TII.get(NewOpc));
   MachineInstrBuilder MIB(MF, I);
 
   if (Opc == TargetOpcode::G_FRAME_INDEX) {
     addOffset(MIB, 0);
   } else {
     MachineOperand &InxOp = I.getOperand(2);
     I.addOperand(InxOp);        // set IndexReg
     InxOp.ChangeToImmediate(1); // set Scale
     MIB.addImm(0).addReg(0);
   }
 
   return constrainSelectedInstRegOperands(I, TII, TRI, RBI);
 }
 
+bool X86InstructionSelector::selectGlobalValue(MachineInstr &I,
+                                               MachineRegisterInfo &MRI,
+                                               MachineFunction &MF) const {
+  unsigned Opc = I.getOpcode();
+
+  if (Opc != TargetOpcode::G_GLOBAL_VALUE)
+    return false;
+
+  auto GV = I.getOperand(1).getGlobal();
+  if (GV->isThreadLocal()) {
+    return false; // TODO: we don't support TLS yet.
+  }
+
+  // Can't handle alternate code models yet.
+  if (TM.getCodeModel() != CodeModel::Small)
+    return 0;
+
+  X86AddressMode AM;
+  AM.GV = GV;
+  AM.GVOpFlags = STI.classifyGlobalReference(GV);
+
+  // TODO: The ABI requires an extra load. not supported yet.
+  if (isGlobalStubReference(AM.GVOpFlags))
+    return false;
+
+  // TODO: This reference is relative to the pic base. not supported yet.
+  if (isGlobalRelativeToPICBase(AM.GVOpFlags))
+    return false;
+
+  if (STI.isPICStyleRIPRel()) {
+    // Use rip-relative addressing.
+    assert(AM.Base.Reg == 0 && AM.IndexReg == 0);
+    AM.Base.Reg = X86::RIP;
+  }
+
+  const unsigned DefReg = I.getOperand(0).getReg();
+  LLT Ty = MRI.getType(DefReg);
+  unsigned NewOpc = getLeaOP(Ty, STI);
+
+  I.setDesc(TII.get(NewOpc));
+  MachineInstrBuilder MIB(MF, I);
+
+  I.RemoveOperand(1);
+  addFullAddress(MIB, AM);
+
+  return constrainSelectedInstRegOperands(I, TII, TRI, RBI);
+}
+
 bool X86InstructionSelector::selectConstant(MachineInstr &I,
                                             MachineRegisterInfo &MRI,
                                             MachineFunction &MF) const {
   if (I.getOpcode() != TargetOpcode::G_CONSTANT)
     return false;
 
   const unsigned DefReg = I.getOperand(0).getReg();
   LLT Ty = MRI.getType(DefReg);

llvm/trunk/lib/Target/X86/X86LegalizerInfo.cpp

for (auto Ty : {s8, s16, s32, p0})
       setAction({MemOp, Ty}, Legal);
 
     // And everything's fine in addrspace 0.
     setAction({MemOp, 1, p0}, Legal);
   }
 
   // Pointer-handling
   setAction({G_FRAME_INDEX, p0}, Legal);
+  setAction({G_GLOBAL_VALUE, p0}, Legal);
 
   setAction({G_GEP, p0}, Legal);
   setAction({G_GEP, 1, s32}, Legal);
 
   for (auto Ty : {s1, s8, s16})
     setAction({G_GEP, 1, Ty}, WidenScalar);
 
   // Constants
for (auto Ty : {s8, s16, s32, s64, p0})
       setAction({MemOp, Ty}, Legal);
 
     // And everything's fine in addrspace 0.
     setAction({MemOp, 1, p0}, Legal);
   }
 
   // Pointer-handling
   setAction({G_FRAME_INDEX, p0}, Legal);
+  setAction({G_GLOBAL_VALUE, p0}, Legal);
 
   setAction({G_GEP, p0}, Legal);
   setAction({G_GEP, 1, s32}, Legal);
   setAction({G_GEP, 1, s64}, Legal);
 
   for (auto Ty : {s1, s8, s16})
     setAction({G_GEP, 1, Ty}, WidenScalar);
 

llvm/trunk/test/CodeGen/X86/GlobalISel/GV.ll

+; NOTE: Assertions have been autogenerated by utils/update_llc_test_checks.py
+; RUN: llc -mtriple=x86_64-linux-gnu    -global-isel -verify-machineinstrs                       < %s -o - | FileCheck %s --check-prefix=X64
+; RUN: llc -mtriple=x86_64-apple-darwin -global-isel -verify-machineinstrs -relocation-model=pic < %s -o - | FileCheck %s --check-prefix=X64_DARWIN_PIC
+; RUN: llc -mtriple=i386-linux-gnu      -global-isel -verify-machineinstrs                       < %s -o - | FileCheck %s --check-prefix=X32
+; RUN: llc -mtriple=x86_64-linux-gnux32 -global-isel -verify-machineinstrs                       < %s -o - | FileCheck %s --check-prefix=X32ABI
+
+@g_int = global i32 0, align 4
+
+; Function Attrs: noinline nounwind optnone uwtable
+define i32* @test_global_ptrv() #3 {
+; X64-LABEL: test_global_ptrv:
+; X64:       # BB#0: # %entry
+; X64-NEXT:    leaq g_int, %rax
+; X64-NEXT:    retq
+;
+; X64_DARWIN_PIC-LABEL: test_global_ptrv:
+; X64_DARWIN_PIC:       ## BB#0: ## %entry
+; X64_DARWIN_PIC-NEXT:    leaq _g_int(%rip), %rax
+; X64_DARWIN_PIC-NEXT:    retq
+;
+; X32-LABEL: test_global_ptrv:
+; X32:       # BB#0: # %entry
+; X32-NEXT:    leal g_int, %eax
+; X32-NEXT:    retl
+;
+; X32ABI-LABEL: test_global_ptrv:
+; X32ABI:       # BB#0: # %entry
+; X32ABI-NEXT:    leal g_int, %eax
+; X32ABI-NEXT:    retq
+entry:
+  ret i32* @g_int
+}
+
+; Function Attrs: noinline nounwind optnone uwtable
+define i32 @test_global_valv() #3 {
+; X64-LABEL: test_global_valv:
+; X64:       # BB#0: # %entry
+; X64-NEXT:    leaq g_int, %rax
+; X64-NEXT:    movl (%rax), %eax
+; X64-NEXT:    retq
+;
+; X64_DARWIN_PIC-LABEL: test_global_valv:
+; X64_DARWIN_PIC:       ## BB#0: ## %entry
+; X64_DARWIN_PIC-NEXT:    leaq _g_int(%rip), %rax
+; X64_DARWIN_PIC-NEXT:    movl (%rax), %eax
+; X64_DARWIN_PIC-NEXT:    retq
+;
+; X32-LABEL: test_global_valv:
+; X32:       # BB#0: # %entry
+; X32-NEXT:    leal g_int, %eax
+; X32-NEXT:    movl (%eax), %eax
+; X32-NEXT:    retl
+;
+; X32ABI-LABEL: test_global_valv:
+; X32ABI:       # BB#0: # %entry
+; X32ABI-NEXT:    leal g_int, %eax
+; X32ABI-NEXT:    movl (%eax), %eax
+; X32ABI-NEXT:    retq
+entry:
+  %0 = load i32, i32* @g_int, align 4
+  ret i32 %0
+}
+

llvm/trunk/test/CodeGen/X86/GlobalISel/legalize-GV.mir

+# RUN: llc -mtriple=x86_64-linux-gnu -global-isel -run-pass=legalizer %s -o - | FileCheck %s --check-prefix=ALL --check-prefix=X64
+# RUN: llc -mtriple=i386-linux-gnu   -global-isel -run-pass=legalizer %s -o - | FileCheck %s --check-prefix=ALL --check-prefix=X32
+--- |
+
+  @g_int = global i32 0, align 4
+
+  define i32* @test_global_ptrv() {
+  entry:
+    ret i32* @g_int
+  }
+...
+---
+name:            test_global_ptrv
+# ALL-LABEL: name:  test_global_ptrv
+alignment:       4
+legalized:       false
+regBankSelected: false
+# ALL:      registers:
+# ALL-NEXT:   - { id: 0, class: _, preferred-register: '' }
+registers:
+  - { id: 0, class: _, preferred-register: '' }
+# ALL:          %0(p0) = G_GLOBAL_VALUE @g_int
+# ALL-NEXT:     %rax = COPY %0(p0)
+# ALL-NEXT:     RET 0, implicit %rax
+body:             |
+  bb.1.entry:
+    %0(p0) = G_GLOBAL_VALUE @g_int
+    %rax = COPY %0(p0)
+    RET 0, implicit %rax
+
+...

llvm/trunk/test/CodeGen/X86/GlobalISel/regbankselect-X86_64.mir

define i32 @test_and_i32() {
     ret i32 %ret
   }
 
   define i64 @test_and_i64() {
     %ret = and i64 undef, undef
     ret i64 %ret
   }
 
+  @g_int = global i32 0, align 4
+
+  define i32* @test_global_ptrv() {
+  entry:
+    ret i32* @g_int
+  }
+  
 ...
 ---
 name:            test_add_i8
 alignment:       4
 legalized:       true
 regBankSelected: false
 selected:        false
 tracksRegLiveness: true

 body:             |
   bb.1 (%ir-block.0):
     %0(s64) = IMPLICIT_DEF
     %1(s64) = G_AND %0, %0
     %rax = COPY %1(s64)
     RET 0, implicit %rax
 
 ...
+---
+name:            test_global_ptrv
+# CHECK-LABEL: name:  test_global_ptrv
+alignment:       4
+legalized:       true
+regBankSelected: false
+# CHECK:       registers:
+# CHECK-NEXT:    - { id: 0, class: gpr, preferred-register: '' }
+registers:
+  - { id: 0, class: _, preferred-register: '' }
+# CHECK:           %0(p0) = G_GLOBAL_VALUE @g_int
+# CHECK-NEXT:      %rax = COPY %0(p0)
+# CHECK-NEXT:      RET 0, implicit %rax
+body:             |
+  bb.1.entry:
+    %0(p0) = G_GLOBAL_VALUE @g_int
+    %rax = COPY %0(p0)
+    RET 0, implicit %rax
+
+...
 

llvm/trunk/test/CodeGen/X86/GlobalISel/select-GV.mir

+# RUN: llc -mtriple=x86_64-linux-gnu                          -global-isel -run-pass=instruction-select -verify-machineinstrs %s -o - | FileCheck %s --check-prefix=CHECK --check-prefix=X64ALL --check-prefix=X64
+# RUN: llc -mtriple=x86_64-apple-darwin -relocation-model=pic -global-isel -run-pass=instruction-select -verify-machineinstrs %s -o - | FileCheck %s --check-prefix=CHECK --check-prefix=X64ALL --check-prefix=X64_DARWIN_PIC
+# RUN: llc -mtriple=i386-linux-gnu                            -global-isel -run-pass=instruction-select -verify-machineinstrs %s -o - | FileCheck %s --check-prefix=CHECK --check-prefix=X32ALL --check-prefix=X32
+# RUN: llc -mtriple=x86_64-linux-gnux32                       -global-isel -run-pass=instruction-select -verify-machineinstrs %s -o - | FileCheck %s --check-prefix=CHECK --check-prefix=X32ALL --check-prefix=X32ABI
+
+--- |
+
+  @g_int = global i32 0, align 4
+
+  define i32* @test_global_ptrv() {
+  entry:
+    ret i32* @g_int
+  }
+
+  define i32 @test_global_valv() {
+  entry:
+    %0 = load i32, i32* @g_int, align 4
+    ret i32 %0
+  }
+
+...
+---
+name:            test_global_ptrv
+# CHECK-LABEL: name:  test_global_ptrv
+alignment:       4
+legalized:       true
+regBankSelected: true
+# X64ALL:              registers:
+# X64ALL-NEXT:           - { id: 0, class: gr64, preferred-register: '' }
+#
+# X32ALL:              registers:
+# X32ALL-NEXT:           - { id: 0, class: gr32, preferred-register: '' }
+registers:
+  - { id: 0, class: gpr, preferred-register: '' }
+# X64:                     %0 = LEA64r _, 1, _, @g_int, _
+# X64-NEXT:                %rax = COPY %0
+# X64-NEXT:                RET 0, implicit %rax
+#
+# X64_DARWIN_PIC:          %0 = LEA64r %rip, 1, _, @g_int, _
+# X64_DARWIN_PIC-NEXT:     %rax = COPY %0
+# X64_DARWIN_PIC-NEXT:     RET 0, implicit %rax
+#
+# X32:                     %0 = LEA32r _, 1, _, @g_int, _
+# X32-NEXT:                %rax = COPY %0
+# X32-NEXT:                RET 0, implicit %rax
+#
+# X32ABI:                  %0 = LEA64_32r _, 1, _, @g_int, _
+# X32ABI-NEXT:             %rax = COPY %0
+# X32ABI-NEXT:             RET 0, implicit %rax
+body:             |
+  bb.1.entry:
+    %0(p0) = G_GLOBAL_VALUE @g_int
+    %rax = COPY %0(p0)
+    RET 0, implicit %rax
+
+...
+---
+name:            test_global_valv
+# CHECK-LABEL: name:  test_global_valv
+alignment:       4
+legalized:       true
+regBankSelected: true
+# X64ALL:              registers:
+# X64ALL-NEXT:           - { id: 0, class: gr32, preferred-register: '' }
+# X64ALL-NEXT:           - { id: 1, class: gr64, preferred-register: '' }
+#
+# X32ALL:              registers:
+# X32ALL-NEXT:           - { id: 0, class: gr32, preferred-register: '' }
+# X32ALL-NEXT:           - { id: 1, class: gr32, preferred-register: '' }
+registers:
+  - { id: 0, class: gpr, preferred-register: '' }
+  - { id: 1, class: gpr, preferred-register: '' }
+# X64:                     %1 = LEA64r _, 1, _, @g_int, _
+# X64-NEXT:                %0 = MOV32rm %1, 1, _, 0, _ :: (load 4 from @g_int)
+# X64-NEXT:                %eax = COPY %0
+# X64-NEXT:                RET 0, implicit %eax
+#
+# X64_DARWIN_PIC:          %1 = LEA64r %rip, 1, _, @g_int, _
+# X64_DARWIN_PIC-NEXT:     %0 = MOV32rm %1, 1, _, 0, _ :: (load 4 from @g_int)
+# X64_DARWIN_PIC-NEXT:     %eax = COPY %0
+# X64_DARWIN_PIC-NEXT:     RET 0, implicit %eax
+#
+# X32:                     %1 = LEA32r _, 1, _, @g_int, _
+# X32-NEXT:                %0 = MOV32rm %1, 1, _, 0, _ :: (load 4 from @g_int)
+# X32-NEXT:                %eax = COPY %0
+# X32-NEXT:                RET 0, implicit %eax
+#
+# X32ABI:                  %1 = LEA64_32r _, 1, _, @g_int, _
+# X32ABI-NEXT:             %0 = MOV32rm %1, 1, _, 0, _ :: (load 4 from @g_int)
+# X32ABI-NEXT:             %eax = COPY %0
+# X32ABI-NEXT:             RET 0, implicit %eax
+body:             |
+  bb.1.entry:
+    %1(p0) = G_GLOBAL_VALUE @g_int
+    %0(s32) = G_LOAD %1(p0) :: (load 4 from @g_int)
+    %eax = COPY %0(s32)
+    RET 0, implicit %eax
+
+...