cmd/internal/obj/arm64: fix incorrect rejection of legal instructions

"BFI $0, R1, $7, R2" is expected to copy bit 0~6 from R1 to R2, and
left R2's other bits unchanged.

But the assembler rejects it with error "illegal bit number", and
BFIW/SBFIZ/SBFIZW/UBFIZ/UBFIZW have the same problem.

This CL fixes that issue and adds corresponding test cases.

fixes #26736

Change-Id: Ie0090a0faa38a49dd9b096a0f435987849800b76
Reviewed-on: https://go-review.googlesource.com/127159
Run-TryBot: Ben Shi <powerman1st@163.com>
Reviewed-by: Cherry Zhang <cherryyz@google.com>

diff --git a/src/cmd/asm/internal/asm/testdata/arm64.s b/src/cmd/asm/internal/asm/testdata/arm64.s
index 859f71a26b579ce4695a7926136a49262a18b580..3a4410f10b4ad421c94335beaea44dc05049f372 100644 (file)
--- a/src/cmd/asm/internal/asm/testdata/arm64.s
+++ b/src/cmd/asm/internal/asm/testdata/arm64.s
@@ -716,6 +716,14 @@ again:
        STPW    (R3, R4), x(SB)
        STPW    (R3, R4), x+8(SB)
 
+// bit field operation
+       BFI     $0, R1, $1, R2      // 220040b3
+       BFIW    $0, R1, $1, R2      // 22000033
+       SBFIZ   $0, R1, $1, R2      // 22004093
+       SBFIZW  $0, R1, $1, R2      // 22000013
+       UBFIZ   $0, R1, $1, R2      // 220040d3
+       UBFIZW  $0, R1, $1, R2      // 22000053
+
 // END
 //
 //     LTYPEE comma

diff --git a/src/cmd/internal/obj/arm64/asm7.go b/src/cmd/internal/obj/arm64/asm7.go
index ff4b1d7ec11a3c0974f47572ec8a9dd1cb3991aa..e3bcce826594c5a8356c508ee0b89c138659b0f5 100644 (file)
--- a/src/cmd/internal/obj/arm64/asm7.go
+++ b/src/cmd/internal/obj/arm64/asm7.go
@@ -3264,10 +3264,16 @@ func (c *ctxt7) asmout(p *obj.Prog, o *Optab, out []uint32) {
                }
                switch p.As {
                case ABFI:
-                       o1 = c.opbfm(p, ABFM, 64-r, s-1, rf, rt)
+                       if r != 0 {
+                               r = 64 - r
+                       }
+                       o1 = c.opbfm(p, ABFM, r, s-1, rf, rt)
 
                case ABFIW:
-                       o1 = c.opbfm(p, ABFMW, 32-r, s-1, rf, rt)
+                       if r != 0 {
+                               r = 32 - r
+                       }
+                       o1 = c.opbfm(p, ABFMW, r, s-1, rf, rt)
 
                case ABFXIL:
                        o1 = c.opbfm(p, ABFM, r, r+s-1, rf, rt)
@@ -3276,10 +3282,16 @@ func (c *ctxt7) asmout(p *obj.Prog, o *Optab, out []uint32) {
                        o1 = c.opbfm(p, ABFMW, r, r+s-1, rf, rt)
 
                case ASBFIZ:
-                       o1 = c.opbfm(p, ASBFM, 64-r, s-1, rf, rt)
+                       if r != 0 {
+                               r = 64 - r
+                       }
+                       o1 = c.opbfm(p, ASBFM, r, s-1, rf, rt)
 
                case ASBFIZW:
-                       o1 = c.opbfm(p, ASBFMW, 32-r, s-1, rf, rt)
+                       if r != 0 {
+                               r = 32 - r
+                       }
+                       o1 = c.opbfm(p, ASBFMW, r, s-1, rf, rt)
 
                case ASBFX:
                        o1 = c.opbfm(p, ASBFM, r, r+s-1, rf, rt)
@@ -3288,10 +3300,16 @@ func (c *ctxt7) asmout(p *obj.Prog, o *Optab, out []uint32) {
                        o1 = c.opbfm(p, ASBFMW, r, r+s-1, rf, rt)
 
                case AUBFIZ:
-                       o1 = c.opbfm(p, AUBFM, 64-r, s-1, rf, rt)
+                       if r != 0 {
+                               r = 64 - r
+                       }
+                       o1 = c.opbfm(p, AUBFM, r, s-1, rf, rt)
 
                case AUBFIZW:
-                       o1 = c.opbfm(p, AUBFMW, 32-r, s-1, rf, rt)
+                       if r != 0 {
+                               r = 32 - r
+                       }
+                       o1 = c.opbfm(p, AUBFMW, r, s-1, rf, rt)
 
                case AUBFX:
                        o1 = c.opbfm(p, AUBFM, r, r+s-1, rf, rt)