Hexagon: Fix Small Data support to handle -G 0 correctly.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@181331 91177308-0d34-0410-b5e6-96231b3b80d8

lib/Target/Hexagon/Hexagon.h

@@ -37,6 +37,8 @@ namespace llvm {
   FunctionPass *createHexagonCFGOptimizer(const HexagonTargetMachine &TM);
 
   FunctionPass *createHexagonSplitTFRCondSets(const HexagonTargetMachine &TM);
+  FunctionPass *createHexagonSplitConst32AndConst64(
+                      const HexagonTargetMachine &TM);
   FunctionPass *createHexagonExpandPredSpillCode(
                       const HexagonTargetMachine &TM);
   FunctionPass *createHexagonHardwareLoops();

lib/Target/Hexagon/HexagonISelLowering.cpp

@@ -948,7 +948,6 @@ HexagonTargetLowering::LowerSELECT_CC(SDValue Op, SelectionDAG &DAG) const {
 SDValue
 HexagonTargetLowering::LowerConstantPool(SDValue Op, SelectionDAG &DAG) const {
   EVT ValTy = Op.getValueType();
-
   DebugLoc dl = Op.getDebugLoc();
   ConstantPoolSDNode *CP = cast<ConstantPoolSDNode>(Op);
   SDValue Res;

lib/Target/Hexagon/HexagonSplitConst32AndConst64.cpp

@@ -0,0 +1,176 @@
+//=== HexagonSplitConst32AndConst64.cpp - split CONST32/Const64 into HI/LO ===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+//
+// When the compiler is invoked with no small data, for instance, with the -G0
+// command line option, then all CONST32_* opcodes should be broken down into
+// appropriate LO and HI instructions. This splitting is done by this pass.
+// The only reason this is not done in the DAG lowering itself is that there
+// is no simple way of getting the register allocator to allot the same hard
+// register to the result of LO and HI instructions. This pass is always
+// scheduled after register allocation.
+//
+//===----------------------------------------------------------------------===//
+#define DEBUG_TYPE "xfer"
+#include "llvm/CodeGen/Passes.h"
+#include "llvm/CodeGen/ScheduleDAGInstrs.h"
+#include "llvm/CodeGen/LatencyPriorityQueue.h"
+#include "llvm/CodeGen/SchedulerRegistry.h"
+#include "llvm/CodeGen/MachineDominators.h"
+#include "llvm/CodeGen/MachineFunctionPass.h"
+#include "llvm/CodeGen/MachineLoopInfo.h"
+#include "llvm/CodeGen/MachineRegisterInfo.h"
+#include "llvm/CodeGen/ScheduleHazardRecognizer.h"
+#include "llvm/Target/TargetMachine.h"
+#include "llvm/Target/TargetInstrInfo.h"
+#include "llvm/Target/TargetRegisterInfo.h"
+#include "llvm/Support/Compiler.h"
+#include "llvm/Support/Debug.h"
+#include "llvm/ADT/Statistic.h"
+#include "llvm/Support/MathExtras.h"
+#include "llvm/CodeGen/MachineInstrBuilder.h"
+#include "HexagonTargetMachine.h"
+#include "HexagonSubtarget.h"
+#include "HexagonMachineFunctionInfo.h"
+#include <map>
+#include <iostream>
+
+#include "llvm/Support/CommandLine.h"
+#define DEBUG_TYPE "xfer"
+
+
+using namespace llvm;
+
+namespace {
+
+class HexagonSplitConst32AndConst64 : public MachineFunctionPass {
+    const HexagonTargetMachine& QTM;
+    const HexagonSubtarget &QST;
+
+ public:
+    static char ID;
+    HexagonSplitConst32AndConst64(const HexagonTargetMachine& TM)
+      : MachineFunctionPass(ID), QTM(TM), QST(*TM.getSubtargetImpl()) {}
+
+    const char *getPassName() const {
+      return "Hexagon Split Const32s and Const64s";
+    }
+    bool runOnMachineFunction(MachineFunction &Fn);
+};
+
+
+char HexagonSplitConst32AndConst64::ID = 0;
+
+
+bool HexagonSplitConst32AndConst64::runOnMachineFunction(MachineFunction &Fn) {
+
+  const TargetInstrInfo *TII = QTM.getInstrInfo();
+
+  // Loop over all of the basic blocks
+  for (MachineFunction::iterator MBBb = Fn.begin(), MBBe = Fn.end();
+       MBBb != MBBe; ++MBBb) {
+    MachineBasicBlock* MBB = MBBb;
+    // Traverse the basic block
+    MachineBasicBlock::iterator MII = MBB->begin();
+    MachineBasicBlock::iterator MIE = MBB->end ();
+    while (MII != MIE) {
+      MachineInstr *MI = MII;
+      int Opc = MI->getOpcode();
+      if (Opc == Hexagon::CONST32_set) {
+        int DestReg = MI->getOperand(0).getReg();
+        MachineOperand &Symbol = MI->getOperand (1);
+
+        BuildMI (*MBB, MII, MI->getDebugLoc(),
+                 TII->get(Hexagon::LO), DestReg).addOperand(Symbol);
+        BuildMI (*MBB, MII, MI->getDebugLoc(),
+                 TII->get(Hexagon::HI), DestReg).addOperand(Symbol);
+        // MBB->erase returns the iterator to the next instruction, which is the
+        // one we want to process next
+        MII = MBB->erase (MI);
+        continue;
+      }
+      else if (Opc == Hexagon::CONST32_set_jt) {
+        int DestReg = MI->getOperand(0).getReg();
+        MachineOperand &Symbol = MI->getOperand (1);
+
+        BuildMI (*MBB, MII, MI->getDebugLoc(),
+                 TII->get(Hexagon::LO_jt), DestReg).addOperand(Symbol);
+        BuildMI (*MBB, MII, MI->getDebugLoc(),
+                 TII->get(Hexagon::HI_jt), DestReg).addOperand(Symbol);
+        // MBB->erase returns the iterator to the next instruction, which is the
+        // one we want to process next
+        MII = MBB->erase (MI);
+        continue;
+      }
+      else if (Opc == Hexagon::CONST32_Label) {
+        int DestReg = MI->getOperand(0).getReg();
+        MachineOperand &Symbol = MI->getOperand (1);
+
+        BuildMI (*MBB, MII, MI->getDebugLoc(),
+                 TII->get(Hexagon::LO_label), DestReg).addOperand(Symbol);
+        BuildMI (*MBB, MII, MI->getDebugLoc(),
+                 TII->get(Hexagon::HI_label), DestReg).addOperand(Symbol);
+        // MBB->erase returns the iterator to the next instruction, which is the
+        // one we want to process next
+        MII = MBB->erase (MI);
+        continue;
+      }
+      else if (Opc == Hexagon::CONST32_Int_Real) {
+        int DestReg = MI->getOperand(0).getReg();
+        int64_t ImmValue = MI->getOperand(1).getImm ();
+
+        BuildMI (*MBB, MII, MI->getDebugLoc(),
+                 TII->get(Hexagon::LOi), DestReg).addImm(ImmValue);
+        BuildMI (*MBB, MII, MI->getDebugLoc(),
+                 TII->get(Hexagon::HIi), DestReg).addImm(ImmValue);
+        MII = MBB->erase (MI);
+        continue;
+      }
+      else if (Opc == Hexagon::CONST64_Int_Real) {
+        int DestReg = MI->getOperand(0).getReg();
+        int64_t ImmValue = MI->getOperand(1).getImm ();
+        unsigned DestLo =
+          QTM.getRegisterInfo()->getSubReg (DestReg, Hexagon::subreg_loreg);
+        unsigned DestHi =
+          QTM.getRegisterInfo()->getSubReg (DestReg, Hexagon::subreg_hireg);
+
+        int32_t LowWord = (ImmValue & 0xFFFFFFFF);
+        int32_t HighWord = (ImmValue >> 32) & 0xFFFFFFFF;
+
+        // Lower Registers Lower Half
+        BuildMI (*MBB, MII, MI->getDebugLoc(),
+                 TII->get(Hexagon::LOi), DestLo).addImm(LowWord);
+        // Lower Registers Higher Half
+        BuildMI (*MBB, MII, MI->getDebugLoc(),
+                 TII->get(Hexagon::HIi), DestLo).addImm(LowWord);
+        // Higher Registers Lower Half
+        BuildMI (*MBB, MII, MI->getDebugLoc(),
+                 TII->get(Hexagon::LOi), DestHi).addImm(HighWord);
+        // Higher Registers Higher Half.
+        BuildMI (*MBB, MII, MI->getDebugLoc(),
+                 TII->get(Hexagon::HIi), DestHi).addImm(HighWord);
+        MII = MBB->erase (MI);
+        continue;
+       }
+      ++MII;
+    }
+  }
+
+  return true;
+}
+
+}
+
+//===----------------------------------------------------------------------===//
+//                         Public Constructor Functions
+//===----------------------------------------------------------------------===//
+
+FunctionPass *
+llvm::createHexagonSplitConst32AndConst64(const HexagonTargetMachine &TM) {
+  return new HexagonSplitConst32AndConst64(TM);
+}

lib/Target/Hexagon/HexagonTargetMachine.cpp

@@ -15,6 +15,7 @@
 #include "Hexagon.h"
 #include "HexagonISelLowering.h"
 #include "HexagonMachineScheduler.h"
+#include "HexagonTargetObjectFile.h"
 #include "llvm/CodeGen/Passes.h"
 #include "llvm/IR/Module.h"
 #include "llvm/PassManager.h"
@@ -156,9 +157,17 @@ bool HexagonPassConfig::addPostRegAlloc() {
 }
 
 bool HexagonPassConfig::addPreSched2() {
+  const HexagonTargetMachine &TM = getHexagonTargetMachine();
+  HexagonTargetObjectFile &TLOF =
+    (HexagonTargetObjectFile&)(getTargetLowering()->getObjFileLowering());
+
   if (getOptLevel() != CodeGenOpt::None)
     addPass(&IfConverterID);
-  return false;
+  if (!TLOF.IsSmallDataEnabled()) {
+    addPass(createHexagonSplitConst32AndConst64(TM));
+    printAndVerify("After hexagon split const32/64 pass");
+  }
+  return true;
 }
 
 bool HexagonPassConfig::addPreEmitPass() {

lib/Target/Hexagon/HexagonTargetObjectFile.cpp

@@ -25,7 +25,8 @@
 using namespace llvm;
 
 static cl::opt<int> SmallDataThreshold("hexagon-small-data-threshold",
-                                cl::init(8), cl::Hidden);
+                                cl::init(8), cl::Hidden,
+                cl::desc("The maximum size of an object in the sdata section"));
 
 void HexagonTargetObjectFile::Initialize(MCContext &Ctx,
                                          const TargetMachine &TM) {
@@ -46,6 +47,11 @@ void HexagonTargetObjectFile::Initialize(MCContext &Ctx,
 static bool IsInSmallSection(uint64_t Size) {
   return Size > 0 && Size <= (uint64_t)SmallDataThreshold;
 }
+
+bool HexagonTargetObjectFile::IsSmallDataEnabled () const {
+  return SmallDataThreshold > 0;
+}
+
 /// IsGlobalInSmallSection - Return true if this global value should be
 /// placed into small data/bss section.
 bool HexagonTargetObjectFile::IsGlobalInSmallSection(const GlobalValue *GV,

lib/Target/Hexagon/HexagonTargetObjectFile.h

@@ -29,6 +29,7 @@ namespace llvm {
     bool IsGlobalInSmallSection(const GlobalValue *GV,
                                 const TargetMachine &TM) const;
 
+    bool IsSmallDataEnabled () const;
     const MCSection* SelectSectionForGlobal(const GlobalValue *GV,
                                             SectionKind Kind,
                                             Mangler *Mang,

test/CodeGen/Hexagon/split-const32-const64.ll

@@ -0,0 +1,26 @@
+; RUN: llc -march=hexagon -mcpu=hexagonv5 -hexagon-small-data-threshold=0 < %s | FileCheck %s
+
+; Check that CONST32/CONST64 instructions are 'not' generated when
+; small-data-threshold is set to 0.
+
+; with immediate value.
+@a = external global i32
+@b = external global i32
+@la = external global i64
+@lb = external global i64
+
+define void @test1() nounwind {
+; CHECK-NOT: CONST32 
+entry:
+  store i32 12345670, i32* @a, align 4
+  store i32 12345670, i32* @b, align 4
+  ret void
+}
+
+define void @test2() nounwind {
+; CHECK-NOT: CONST64
+entry:
+  store i64 1234567890123, i64* @la, align 8
+  store i64 1234567890123, i64* @lb, align 8
+  ret void
+}