cmd/internal/obj/arm: report invalid .S/.P/.W suffix in ARM instructions

Many instructions can not have a .S suffix, such as MULS, SWI, CLZ,
CMP, STREX and others. And so do .P and .W suffixes. Even wrong
assembly code is generated for some instructions with invalid
suffixes.

This patch tries to simplify .S/.W/.P checks. And a wrong assembly
test for arm is added.

fixes #20377

Change-Id: Iba1c99d9e6b7b16a749b4d93ca2102e17c5822fe
Reviewed-on: https://go-review.googlesource.com/43561Reviewed-by: Cherry Zhang <cherryyz@google.com>

src/cmd/asm/internal/asm/endtoend_test.go

@@ -371,6 +371,10 @@ func TestARMEndToEnd(t *testing.T) {
 	}
 }
 
+func TestARMErrors(t *testing.T) {
+	testErrors(t, "arm", "armerror")
+}
+
 func TestARM64EndToEnd(t *testing.T) {
 	testEndToEnd(t, "arm64", "arm64")
 }

src/cmd/asm/internal/asm/testdata/arm.s

@@ -47,7 +47,7 @@ TEXT	foo(SB), DUPOK|NOSPLIT, $0
 //	{
 //		outcode($1, $2, &$3, 0, &$5);
 //	}
-	CLZ.S	R1, R2
+	CLZ	R1, R2
 
 //
 // MOVW
@@ -114,9 +114,9 @@ TEXT	foo(SB), DUPOK|NOSPLIT, $0
 //	{
 //		outcode($1, $2, &$3, $5, &nullgen);
 //	}
-	CMP.S	$1, R2
-	CMP.S	R1<<R2, R3
-	CMP.S	R1, R2
+	CMP	$1, R2
+	CMP	R1<<R2, R3
+	CMP	R1, R2
 
 //
 // MOVM
@@ -132,7 +132,7 @@ TEXT	foo(SB), DUPOK|NOSPLIT, $0
 //	}
 	MOVM	0(R1), [R2,R5,R8,g] // MOVM	(R1), [R2,R5,R8,g]
 	MOVM	(R1), [R2-R5] // MOVM (R1), [R2,R3,R4,R5]
-	MOVM.S	(R1), [R2]
+	MOVM	(R1), [R2]
 
 //	LTYPE8 cond '[' reglist ']' ',' ioreg
 //	{
@@ -145,7 +145,7 @@ TEXT	foo(SB), DUPOK|NOSPLIT, $0
 //	}
 	MOVM	[R2,R5,R8,g], 0(R1) // MOVM	[R2,R5,R8,g], (R1)
 	MOVM	[R2-R5], (R1) // MOVM [R2,R3,R4,R5], (R1)
-	MOVM.S	[R2], (R1)
+	MOVM	[R2], (R1)
 
 //
 // SWAP
@@ -154,19 +154,19 @@ TEXT	foo(SB), DUPOK|NOSPLIT, $0
 //	{
 //		outcode($1, $2, &$5, int32($3.Reg), &$7);
 //	}
-	STREX.S	R1, (R2), R3 // STREX.S (R2), R1, R3
+	STREX	R1, (R2), R3 // STREX (R2), R1, R3
 
 //	LTYPE9 cond reg ',' ireg
 //	{
 //		outcode($1, $2, &$5, int32($3.Reg), &$3);
 //	}
-	STREX.S	R1, (R2) // STREX.S (R2), R1, R1
+	STREX	R1, (R2) // STREX (R2), R1, R1
 
 //	LTYPE9 cond comma ireg ',' reg
 //	{
 //		outcode($1, $2, &$4, int32($6.Reg), &$6);
 //	}
-	STREX.S	(R2), R3 // STREX.S (R2), R3, R3
+	STREX	(R2), R3 // STREX (R2), R3, R3
 
 //
 // word
@@ -184,26 +184,26 @@ TEXT	foo(SB), DUPOK|NOSPLIT, $0
 //	{
 //		outcode($1, $2, &$3, 0, &$5);
 //	}
-	ABSF.S	F1, F2
+	ABSF	F1, F2
 
 //	LTYPEK cond frcon ',' freg
 //	{
 //		outcode($1, $2, &$3, 0, &$5);
 //	}
-	ADDD.S	F1, F2
+	ADDD	F1, F2
 	MOVF	$0.5, F2 // MOVF $(0.5), F2
 
 //	LTYPEK cond frcon ',' LFREG ',' freg
 //	{
 //		outcode($1, $2, &$3, $5, &$7);
 //	}
-	ADDD.S	F1, F2, F3
+	ADDD	F1, F2, F3
 
 //	LTYPEL cond freg ',' freg
 //	{
 //		outcode($1, $2, &$3, int32($5.Reg), &nullgen);
 //	}
-	CMPD.S	F1, F2
+	CMPD	F1, F2
 
 //
 // MCR MRC

src/cmd/asm/internal/asm/testdata/armerror.s

+// Copyright 2017 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+TEXT errors(SB),$0
+	MULS.S	R1, R2, R3, R4     // ERROR "invalid .S suffix"
+	ADD.P	R1, R2, R3         // ERROR "invalid .P suffix"
+	SUB.W	R2, R3             // ERROR "invalid .W suffix"
+	BL	4(R4)              // ERROR "non-zero offset"
+	END

src/cmd/internal/obj/arm/asm5.go

@@ -597,6 +597,64 @@ func (c *ctxt5) asmoutnacl(origPC int32, p *obj.Prog, o *Optab, out []uint32) in
 	return size
 }
 
+const (
+	T_SBIT = 1 << 0
+	T_PBIT = 1 << 1
+	T_WBIT = 1 << 2
+)
+
+var mayHaveSuffix = map[obj.As]uint8{
+	// bit logic
+	AAND: T_SBIT,
+	AEOR: T_SBIT,
+	AORR: T_SBIT,
+	ABIC: T_SBIT,
+	// arithmatic
+	ASUB: T_SBIT,
+	AADD: T_SBIT,
+	ASBC: T_SBIT,
+	AADC: T_SBIT,
+	ARSB: T_SBIT,
+	ARSC: T_SBIT,
+	// mov
+	AMVN:   T_SBIT,
+	AMOVW:  T_SBIT | T_PBIT | T_WBIT,
+	AMOVB:  T_SBIT | T_PBIT | T_WBIT,
+	AMOVBS: T_SBIT | T_PBIT | T_WBIT,
+	AMOVBU: T_SBIT | T_PBIT | T_WBIT,
+	AMOVH:  T_SBIT | T_PBIT | T_WBIT,
+	AMOVHS: T_SBIT | T_PBIT | T_WBIT,
+	AMOVHU: T_SBIT | T_PBIT | T_WBIT,
+	AMOVM:  T_PBIT | T_WBIT,
+	// shift
+	ASRL: T_SBIT,
+	ASRA: T_SBIT,
+	ASLL: T_SBIT,
+	// mul
+	AMUL:   T_SBIT,
+	AMULU:  T_SBIT,
+	AMULL:  T_SBIT,
+	AMULLU: T_SBIT,
+	// mula
+	AMULA:   T_SBIT,
+	AMULAL:  T_SBIT,
+	AMULALU: T_SBIT,
+	// MRC/MCR
+	AMRC: T_SBIT,
+}
+
+func checkBits(ctxt *obj.Link, p *obj.Prog) {
+	if p.Scond&C_SBIT != 0 && mayHaveSuffix[p.As]&T_SBIT == 0 {
+		ctxt.Diag("invalid .S suffix: %v", p)
+	}
+	if p.Scond&C_PBIT != 0 && mayHaveSuffix[p.As]&T_PBIT == 0 {
+		ctxt.Diag("invalid .P suffix: %v", p)
+	}
+	if p.Scond&C_WBIT != 0 && mayHaveSuffix[p.As]&T_WBIT == 0 {
+		ctxt.Diag("invalid .W suffix: %v", p)
+	}
+}
+
 func span5(ctxt *obj.Link, cursym *obj.LSym, newprog obj.ProgAlloc) {
 	var p *obj.Prog
 	var op *obj.Prog
@@ -675,6 +733,9 @@ func span5(ctxt *obj.Link, cursym *obj.LSym, newprog obj.ProgAlloc) {
 		if p.As == AMOVW && p.To.Type == obj.TYPE_REG && p.To.Reg == REGPC && p.Scond&C_SCOND == C_SCOND_NONE {
 			c.flushpool(p, 0, 0)
 		}
+
+		checkBits(ctxt, p)
+
 		pc += int32(m)
 	}
 
@@ -2032,9 +2093,6 @@ func (c *ctxt5) asmout(p *obj.Prog, o *Optab, out []uint32) {
 		if p.Scond&C_UBIT != 0 {
 			o1 |= 1 << 23
 		}
-		if p.Scond&C_SBIT != 0 {
-			o1 |= 1 << 22
-		}
 		if p.Scond&C_WBIT != 0 {
 			o1 |= 1 << 21
 		}
@@ -2610,9 +2668,6 @@ func (c *ctxt5) oprrr(p *obj.Prog, a obj.As, sc int) uint32 {
 	if sc&C_SBIT != 0 {
 		o |= 1 << 20
 	}
-	if sc&(C_PBIT|C_WBIT) != 0 {
-		c.ctxt.Diag(".nil/.W on dp instruction")
-	}
 	switch a {
 	case ADIVHW:
 		return o | 0x71<<20 | 0xf<<12 | 0x1<<4
@@ -2666,6 +2721,9 @@ func (c *ctxt5) oprrr(p *obj.Prog, a obj.As, sc int) uint32 {
 		return o | 0xc<<21
 
 	case AMOVB, AMOVH, AMOVW:
+		if sc&(C_PBIT|C_WBIT) != 0 {
+			c.ctxt.Diag("invalid .P/.W suffix: %v", p)
+		}
 		return o | 0xd<<21
 	case ABIC:
 		return o | 0xe<<21
@@ -2799,9 +2857,6 @@ func (c *ctxt5) oprrr(p *obj.Prog, a obj.As, sc int) uint32 {
 }
 
 func (c *ctxt5) opbra(p *obj.Prog, a obj.As, sc int) uint32 {
-	if sc&(C_SBIT|C_PBIT|C_WBIT) != 0 {
-		c.ctxt.Diag("%v: .nil/.nil/.W on bra instruction", p)
-	}
 	sc &= C_SCOND
 	sc ^= C_SCOND_XOR
 	if a == ABL || a == obj.ADUFFZERO || a == obj.ADUFFCOPY {
@@ -2939,9 +2994,6 @@ func (c *ctxt5) olhrr(i int, b int, r int, sc int) uint32 {
 }
 
 func (c *ctxt5) ofsr(a obj.As, r int, v int32, b int, sc int, p *obj.Prog) uint32 {
-	if sc&C_SBIT != 0 {
-		c.ctxt.Diag(".nil on FLDR/FSTR instruction: %v", p)
-	}
 	o := ((uint32(sc) & C_SCOND) ^ C_SCOND_XOR) << 28
 	if sc&C_PBIT == 0 {
 		o |= 1 << 24