ARM: sort register lists by encoding in push/pop instructions.

For example we were producing

    push {r8, r10, r11, r4, r5, r7, lr}

This is misleading (r4, r5 and r7 are actually pushed before the rest), and
other components (stack folding recently) often forget to deal with the extra
complexity coming from the different order, leading to miscompiles. Finally, we
warn about our own code in -no-integrated-as mode without this, which is really
not a good idea.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@286866 91177308-0d34-0410-b5e6-96231b3b80d8

lib/Target/ARM/ARMFrameLowering.cpp

@@ -893,10 +893,12 @@ void ARMFrameLowering::emitPushInst(MachineBasicBlock &MBB,
                                     unsigned MIFlags) const {
   MachineFunction &MF = *MBB.getParent();
   const TargetInstrInfo &TII = *MF.getSubtarget().getInstrInfo();
+  const TargetRegisterInfo &TRI = *STI.getRegisterInfo();
 
   DebugLoc DL;
 
-  SmallVector<std::pair<unsigned,bool>, 4> Regs;
+  typedef std::pair<unsigned, bool> RegAndKill;
+  SmallVector<RegAndKill, 4> Regs;
   unsigned i = CSI.size();
   while (i != 0) {
     unsigned LastReg = 0;
@@ -927,6 +929,11 @@ void ARMFrameLowering::emitPushInst(MachineBasicBlock &MBB,
 
     if (Regs.empty())
       continue;
+
+    std::sort(Regs.begin(), Regs.end(), [&](RegAndKill &LHS, RegAndKill &RHS) {
+      return TRI.getEncodingValue(LHS.first) < TRI.getEncodingValue(RHS.first);
+    });
+
     if (Regs.size() > 1 || StrOpc== 0) {
       MachineInstrBuilder MIB =
         AddDefaultPred(BuildMI(MBB, MI, DL, TII.get(StmOpc), ARM::SP)
@@ -960,6 +967,7 @@ void ARMFrameLowering::emitPopInst(MachineBasicBlock &MBB,
                                    unsigned NumAlignedDPRCS2Regs) const {
   MachineFunction &MF = *MBB.getParent();
   const TargetInstrInfo &TII = *MF.getSubtarget().getInstrInfo();
+  const TargetRegisterInfo &TRI = *STI.getRegisterInfo();
   ARMFunctionInfo *AFI = MF.getInfo<ARMFunctionInfo>();
   DebugLoc DL;
   bool isTailCall = false;
@@ -1012,6 +1020,11 @@ void ARMFrameLowering::emitPopInst(MachineBasicBlock &MBB,
 
     if (Regs.empty())
       continue;
+
+    std::sort(Regs.begin(), Regs.end(), [&](unsigned &LHS, unsigned &RHS) {
+      return TRI.getEncodingValue(LHS) < TRI.getEncodingValue(RHS);
+    });
+
     if (Regs.size() > 1 || LdrOpc == 0) {
       MachineInstrBuilder MIB =
         AddDefaultPred(BuildMI(MBB, MI, DL, TII.get(LdmOpc), ARM::SP)

lib/Target/ARM/InstPrinter/ARMInstPrinter.cpp

@@ -726,6 +726,12 @@ void ARMInstPrinter::printPKHASRShiftImm(const MCInst *MI, unsigned OpNum,
 void ARMInstPrinter::printRegisterList(const MCInst *MI, unsigned OpNum,
                                        const MCSubtargetInfo &STI,
                                        raw_ostream &O) {
+  assert(std::is_sorted(MI->begin() + OpNum, MI->end(),
+                        [&](const MCOperand &LHS, const MCOperand &RHS) {
+                          return MRI.getEncodingValue(LHS.getReg()) <
+                                 MRI.getEncodingValue(RHS.getReg());
+                        }));
+
   O << "{";
   for (unsigned i = OpNum, e = MI->getNumOperands(); i != e; ++i) {
     if (i != OpNum)

lib/Target/ARM/MCTargetDesc/ARMMCCodeEmitter.cpp

@@ -1545,8 +1545,15 @@ getRegisterListOpValue(const MCInst &MI, unsigned Op,
     else
       Binary |= NumRegs * 2;
   } else {
+    const MCRegisterInfo &MRI = *CTX.getRegisterInfo();
+    assert(std::is_sorted(MI.begin() + Op, MI.end(),
+                          [&](const MCOperand &LHS, const MCOperand &RHS) {
+                            return MRI.getEncodingValue(LHS.getReg()) <
+                                   MRI.getEncodingValue(RHS.getReg());
+                          }));
+
     for (unsigned I = Op, E = MI.getNumOperands(); I < E; ++I) {
-      unsigned RegNo = CTX.getRegisterInfo()->getEncodingValue(MI.getOperand(I).getReg());
+      unsigned RegNo = MRI.getEncodingValue(MI.getOperand(I).getReg());
       Binary |= 1 << RegNo;
     }
   }

test/CodeGen/ARM/swifterror.ll

@@ -415,7 +415,7 @@ define swiftcc void @swifterror_reg_clobber(%swift_error** nocapture %err) {
 
 ; CHECK-ARMV7-LABEL: _params_in_reg
 ; Store callee saved registers excluding swifterror.
-; CHECK-ARMV7:  push    {r8, r10, r11, r4, r5, r7, lr}
+; CHECK-ARMV7:  push    {r4, r5, r7, r8, r10, r11, lr}
 ; Store swiftself (r10) and swifterror (r6).
 ; CHECK-ARMV7-DAG:  str     r6, [s[[STK1:.*]]]
 ; CHECK-ARMV7-DAG:  str     r10, [s[[STK2:.*]]]
@@ -440,7 +440,7 @@ define swiftcc void @swifterror_reg_clobber(%swift_error** nocapture %err) {
 ; CHECK-ARMV7:  mov     r2, r5
 ; CHECK-ARMV7:  mov     r3, r4
 ; CHECK-ARMV7:  bl      _params_in_reg2
-; CHECK-ARMV7:  pop     {r8, r10, r11, r4, r5, r7, pc}
+; CHECK-ARMV7:  pop     {r4, r5, r7,  r8, r10, r11, pc}
 define swiftcc void @params_in_reg(i32, i32, i32, i32, i8* swiftself, %swift_error** nocapture swifterror %err) {
   %error_ptr_ref = alloca swifterror %swift_error*, align 8
   store %swift_error* null, %swift_error** %error_ptr_ref
@@ -451,7 +451,7 @@ define swiftcc void @params_in_reg(i32, i32, i32, i32, i8* swiftself, %swift_err
 declare swiftcc void @params_in_reg2(i32, i32, i32, i32, i8* swiftself, %swift_error** nocapture swifterror %err)
 
 ; CHECK-ARMV7-LABEL: params_and_return_in_reg
-; CHECK-ARMV7:  push    {r8, r10, r11, r4, r5, r7, lr}
+; CHECK-ARMV7:  push    {r4, r5, r7, r8, r10, r11, lr}
 ; Store swifterror and swiftself
 ; CHECK-ARMV7:  mov     r4, r6
 ; CHECK-ARMV7:  str     r10, [s[[STK1:.*]]]
@@ -502,7 +502,7 @@ declare swiftcc void @params_in_reg2(i32, i32, i32, i32, i8* swiftself, %swift_e
 ; CHECK-ARMV7:  mov     r1, r4
 ; CHECK-ARMV7:  mov     r2, r8
 ; CHECK-ARMV7:  mov     r3, r11
-; CHECK-ARMV7:  pop     {r8, r10, r11, r4, r5, r7, pc}
+; CHECK-ARMV7:  pop     {r4, r5, r7, r8, r10, r11, pc}
 define swiftcc { i32, i32, i32, i32} @params_and_return_in_reg(i32, i32, i32, i32, i8* swiftself, %swift_error** nocapture swifterror %err) {
   %error_ptr_ref = alloca swifterror %swift_error*, align 8
   store %swift_error* null, %swift_error** %error_ptr_ref