[AArch64] Add support for the SPE-EEF feature

This is an addition to the existing Statistical Profiling extension, which
introduces an extra system register that is enabled by the new 'spe-eef'
subtarget feature.

Patch written by Simon Tatham.

Reviewed By: ostannard

Differential Revision: https://reviews.llvm.org/D92391

Author: pratlucas

llvm/lib/Target/AArch64/AArch64.td

@@ -415,6 +415,9 @@ def FeatureLS64 : SubtargetFeature<"ls64", "HasLS64",
 def FeatureBRBE : SubtargetFeature<"brbe", "HasBRBE",
     "true", "Enable Branch Record Buffer Extension">;
 
+def FeatureSPE_EEF : SubtargetFeature<"spe-eef", "HasSPE_EEF",
+    "true", "Enable extra register in the Statistical Profiling Extension">;
+
 def FeatureFineGrainedTraps : SubtargetFeature<"fgt", "HasFineGrainedTraps",
     "true", "Enable fine grained virtualization traps extension">;
 

llvm/lib/Target/AArch64/AArch64InstrInfo.td

@@ -159,6 +159,8 @@ def HasLS64          : Predicate<"Subtarget->hasLS64()">,
                        AssemblerPredicate<(all_of FeatureLS64), "ls64">;
 def HasBRBE          : Predicate<"Subtarget->hasBRBE()">,
                        AssemblerPredicate<(all_of FeatureBRBE), "brbe">;
+def HasSPE_EEF       : Predicate<"Subtarget->hasSPE_EEF()">,
+                       AssemblerPredicate<(all_of FeatureSPE_EEF), "spe-eef">;
 def IsLE             : Predicate<"Subtarget->isLittleEndian()">;
 def IsBE             : Predicate<"!Subtarget->isLittleEndian()">;
 def IsWindows        : Predicate<"Subtarget->isTargetWindows()">;

llvm/lib/Target/AArch64/AArch64Subtarget.h

@@ -185,6 +185,7 @@ class AArch64Subtarget final : public AArch64GenSubtargetInfo {
   bool HasETE = false;
   bool HasTRBE = false;
   bool HasBRBE = false;
+  bool HasSPE_EEF = false;
 
   // HasZeroCycleRegMove - Has zero-cycle register mov instructions.
   bool HasZeroCycleRegMove = false;

llvm/lib/Target/AArch64/AArch64SystemOperands.td

@@ -1593,6 +1593,10 @@ foreach n = 0-31 in {
 }
 }
 
+// Statistical Profiling Extension system register
+let Requires = [{ {AArch64::FeatureSPE_EEF} }] in
+def : RWSysReg<"PMSNEVFR_EL1",      0b11, 0b000, 0b1001, 0b1001, 0b001>;
+
 // Cyclone specific system registers
 //                                 Op0    Op1     CRn     CRm    Op2
 let Requires = [{ {AArch64::ProcAppleA7} }] in

llvm/test/MC/AArch64/spe.s

@@ -0,0 +1,6 @@
+// RUN: llvm-mc -triple aarch64 -mattr +spe-eef -show-encoding %s 2>%t | FileCheck %s
+
+msr PMSNEVFR_EL1, x0
+mrs x1, PMSNEVFR_EL1
+// CHECK: msr     PMSNEVFR_EL1, x0        // encoding: [0x20,0x99,0x18,0xd5]
+// CHECK: mrs     x1, PMSNEVFR_EL1        // encoding: [0x21,0x99,0x38,0xd5]