cmd/compile: add dedicated ARM64BitField aux type

The goal here is improved AuxInt printing in ssa.html.
Instead of displaying an inscrutable encoded integer,
it displays something like

v25 (28) = UBFX <int> [lsb=4,width=8] v52

which is much nicer for debugging.

Change-Id: I40713ff7f4a857c4557486cdf73c2dff137511ca
Reviewed-on: https://go-review.googlesource.com/c/go/+/221420
Run-TryBot: Josh Bleecher Snyder <josharian@gmail.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Cherry Zhang <cherryyz@google.com>

6 files changed, 36 insertions, 31 deletions

diff --git a/src/cmd/compile/internal/ssa/check.go b/src/cmd/compile/internal/ssa/check.go
index 4e258fe82b..a6746805f7 100644
--- a/src/cmd/compile/internal/ssa/check.go
+++ b/src/cmd/compile/internal/ssa/check.go
@@ -141,7 +141,7 @@ func checkFunc(f *Func) {
 					f.Fatalf("bad int32 AuxInt value for %v", v)
 				}
 				canHaveAuxInt = true
-			case auxInt64, auxFloat64:
+			case auxInt64, auxFloat64, auxARM64BitField:
 				canHaveAuxInt = true
 			case auxInt128:
 				// AuxInt must be zero, so leave canHaveAuxInt set to false.
diff --git a/src/cmd/compile/internal/ssa/gen/ARM64Ops.go b/src/cmd/compile/internal/ssa/gen/ARM64Ops.go
index 51a610fc76..4e18fb0f76 100644
--- a/src/cmd/compile/internal/ssa/gen/ARM64Ops.go
+++ b/src/cmd/compile/internal/ssa/gen/ARM64Ops.go
@@ -338,17 +338,17 @@ func init() {
 		// bitfield ops
 		// for all bitfield ops lsb is auxInt>>8, width is auxInt&0xff
 		// insert low width bits of arg1 into the result starting at bit lsb, copy other bits from arg0
-		{name: "BFI", argLength: 2, reg: gp21nog, asm: "BFI", aux: "Int64", resultInArg0: true},
+		{name: "BFI", argLength: 2, reg: gp21nog, asm: "BFI", aux: "ARM64BitField", resultInArg0: true},
 		// extract width bits of arg1 starting at bit lsb and insert at low end of result, copy other bits from arg0
-		{name: "BFXIL", argLength: 2, reg: gp21nog, asm: "BFXIL", aux: "Int64", resultInArg0: true},
+		{name: "BFXIL", argLength: 2, reg: gp21nog, asm: "BFXIL", aux: "ARM64BitField", resultInArg0: true},
 		// insert low width bits of arg0 into the result starting at bit lsb, bits to the left of the inserted bit field are set to the high/sign bit of the inserted bit field, bits to the right are zeroed
-		{name: "SBFIZ", argLength: 1, reg: gp11, asm: "SBFIZ", aux: "Int64"},
+		{name: "SBFIZ", argLength: 1, reg: gp11, asm: "SBFIZ", aux: "ARM64BitField"},
 		// extract width bits of arg0 starting at bit lsb and insert at low end of result, remaining high bits are set to the high/sign bit of the extracted bitfield
-		{name: "SBFX", argLength: 1, reg: gp11, asm: "SBFX", aux: "Int64"},
+		{name: "SBFX", argLength: 1, reg: gp11, asm: "SBFX", aux: "ARM64BitField"},
 		// insert low width bits of arg0 into the result starting at bit lsb, bits to the left and right of the inserted bit field are zeroed
-		{name: "UBFIZ", argLength: 1, reg: gp11, asm: "UBFIZ", aux: "Int64"},
+		{name: "UBFIZ", argLength: 1, reg: gp11, asm: "UBFIZ", aux: "ARM64BitField"},
 		// extract width bits of arg0 starting at bit lsb and insert at low end of result, remaining high bits are zeroed
-		{name: "UBFX", argLength: 1, reg: gp11, asm: "UBFX", aux: "Int64"},
+		{name: "UBFX", argLength: 1, reg: gp11, asm: "UBFX", aux: "ARM64BitField"},
 
 		// moves
 		{name: "MOVDconst", argLength: 0, reg: gp01, aux: "Int64", asm: "MOVD", typ: "UInt64", rematerializeable: true},      // 32 low bits of auxint
diff --git a/src/cmd/compile/internal/ssa/gen/rulegen.go b/src/cmd/compile/internal/ssa/gen/rulegen.go
index 4f404af8e7..2a10f2fa25 100644
--- a/src/cmd/compile/internal/ssa/gen/rulegen.go
+++ b/src/cmd/compile/internal/ssa/gen/rulegen.go
@@ -1298,7 +1298,7 @@ func parseValue(val string, arch arch, loc string) (op opData, oparch, typ, auxi
 
 func opHasAuxInt(op opData) bool {
 	switch op.aux {
-	case "Bool", "Int8", "Int16", "Int32", "Int64", "Int128", "Float32", "Float64", "SymOff", "SymValAndOff", "TypSize":
+	case "Bool", "Int8", "Int16", "Int32", "Int64", "Int128", "Float32", "Float64", "SymOff", "SymValAndOff", "TypSize", "ARM64BitField":
 		return true
 	}
 	return false
diff --git a/src/cmd/compile/internal/ssa/op.go b/src/cmd/compile/internal/ssa/op.go
index ec9e7863a0..c32f5c730e 100644
--- a/src/cmd/compile/internal/ssa/op.go
+++ b/src/cmd/compile/internal/ssa/op.go
@@ -68,23 +68,24 @@ type regInfo struct {
 type auxType int8
 
 const (
-	auxNone         auxType = iota
-	auxBool                 // auxInt is 0/1 for false/true
-	auxInt8                 // auxInt is an 8-bit integer
-	auxInt16                // auxInt is a 16-bit integer
-	auxInt32                // auxInt is a 32-bit integer
-	auxInt64                // auxInt is a 64-bit integer
-	auxInt128               // auxInt represents a 128-bit integer.  Always 0.
-	auxFloat32              // auxInt is a float32 (encoded with math.Float64bits)
-	auxFloat64              // auxInt is a float64 (encoded with math.Float64bits)
-	auxString               // aux is a string
-	auxSym                  // aux is a symbol (a *gc.Node for locals or an *obj.LSym for globals)
-	auxSymOff               // aux is a symbol, auxInt is an offset
-	auxSymValAndOff         // aux is a symbol, auxInt is a ValAndOff
-	auxTyp                  // aux is a type
-	auxTypSize              // aux is a type, auxInt is a size, must have Aux.(Type).Size() == AuxInt
-	auxCCop                 // aux is a ssa.Op that represents a flags-to-bool conversion (e.g. LessThan)
-	auxArchSpecific         // aux type is specific to a particular backend (see the relevant op for the actual type)
+	auxNone          auxType = iota
+	auxBool                  // auxInt is 0/1 for false/true
+	auxInt8                  // auxInt is an 8-bit integer
+	auxInt16                 // auxInt is a 16-bit integer
+	auxInt32                 // auxInt is a 32-bit integer
+	auxInt64                 // auxInt is a 64-bit integer
+	auxInt128                // auxInt represents a 128-bit integer.  Always 0.
+	auxFloat32               // auxInt is a float32 (encoded with math.Float64bits)
+	auxFloat64               // auxInt is a float64 (encoded with math.Float64bits)
+	auxString                // aux is a string
+	auxSym                   // aux is a symbol (a *gc.Node for locals or an *obj.LSym for globals)
+	auxSymOff                // aux is a symbol, auxInt is an offset
+	auxSymValAndOff          // aux is a symbol, auxInt is a ValAndOff
+	auxTyp                   // aux is a type
+	auxTypSize               // aux is a type, auxInt is a size, must have Aux.(Type).Size() == AuxInt
+	auxCCop                  // aux is a ssa.Op that represents a flags-to-bool conversion (e.g. LessThan)
+	auxARM64BitField         // aux is an arm64 bitfield lsb and width packed into auxint
+	auxArchSpecific          // aux type is specific to a particular backend (see the relevant op for the actual type)
 )
 
 // A SymEffect describes the effect that an SSA Value has on the variable
diff --git a/src/cmd/compile/internal/ssa/opGen.go b/src/cmd/compile/internal/ssa/opGen.go
index b951065e7c..1111316d9b 100644
--- a/src/cmd/compile/internal/ssa/opGen.go
+++ b/src/cmd/compile/internal/ssa/opGen.go
@@ -17359,7 +17359,7 @@ var opcodeTable = [...]opInfo{
 	},
 	{
 		name:         "BFI",
-		auxType:      auxInt64,
+		auxType:      auxARM64BitField,
 		argLen:       2,
 		resultInArg0: true,
 		asm:          arm64.ABFI,
@@ -17375,7 +17375,7 @@ var opcodeTable = [...]opInfo{
 	},
 	{
 		name:         "BFXIL",
-		auxType:      auxInt64,
+		auxType:      auxARM64BitField,
 		argLen:       2,
 		resultInArg0: true,
 		asm:          arm64.ABFXIL,
@@ -17391,7 +17391,7 @@ var opcodeTable = [...]opInfo{
 	},
 	{
 		name:    "SBFIZ",
-		auxType: auxInt64,
+		auxType: auxARM64BitField,
 		argLen:  1,
 		asm:     arm64.ASBFIZ,
 		reg: regInfo{
@@ -17405,7 +17405,7 @@ var opcodeTable = [...]opInfo{
 	},
 	{
 		name:    "SBFX",
-		auxType: auxInt64,
+		auxType: auxARM64BitField,
 		argLen:  1,
 		asm:     arm64.ASBFX,
 		reg: regInfo{
@@ -17419,7 +17419,7 @@ var opcodeTable = [...]opInfo{
 	},
 	{
 		name:    "UBFIZ",
-		auxType: auxInt64,
+		auxType: auxARM64BitField,
 		argLen:  1,
 		asm:     arm64.AUBFIZ,
 		reg: regInfo{
@@ -17433,7 +17433,7 @@ var opcodeTable = [...]opInfo{
 	},
 	{
 		name:    "UBFX",
-		auxType: auxInt64,
+		auxType: auxARM64BitField,
 		argLen:  1,
 		asm:     arm64.AUBFX,
 		reg: regInfo{
diff --git a/src/cmd/compile/internal/ssa/value.go b/src/cmd/compile/internal/ssa/value.go
index c08eba3d44..b877220211 100644
--- a/src/cmd/compile/internal/ssa/value.go
+++ b/src/cmd/compile/internal/ssa/value.go
@@ -175,6 +175,10 @@ func (v *Value) auxString() string {
 		return fmt.Sprintf(" [%d]", v.AuxInt32())
 	case auxInt64, auxInt128:
 		return fmt.Sprintf(" [%d]", v.AuxInt)
+	case auxARM64BitField:
+		lsb := getARM64BFlsb(v.AuxInt)
+		width := getARM64BFwidth(v.AuxInt)
+		return fmt.Sprintf(" [lsb=%d,width=%d]", lsb, width)
 	case auxFloat32, auxFloat64:
 		return fmt.Sprintf(" [%g]", v.AuxFloat())
 	case auxString: