cmd/internal/obj/arm64: improve comment and signature of pcAlignPadLe…

…ngth The function just calculates the number of needed padding bytes, instead of actually carrying out the alignment operation. And it has the context argument at the end of the argument list, while contexts idiomatically come first. Indeed, this is the only case in cmd/internal/obj where ctxt is not the only argument and does not come first. Fix those two nits; no functional change intended. Suggested by Ian during review of CL 479815 (that introduces a copy of this helper into the loong64 port). Change-Id: Ieb221ead23282abe6e04804d537e1234c7ab21d0 Reviewed-on: https://go-review.googlesource.com/c/go/+/483155 Run-TryBot: Cherry Mui <cherryyz@google.com> Reviewed-by: Cherry Mui <cherryyz@google.com> TryBot-Result: Gopher Robot <gobot@golang.org> Reviewed-by: Michael Knyszek <mknyszek@google.com>
ruchirj · Apr 11, 2023 · 58eaecb · 58eaecb
1 parent f00c541
commit 58eaecb
Showing 1 changed file with 6 additions and 5 deletions.
diff --git a/src/cmd/internal/obj/arm64/asm7.go b/src/cmd/internal/obj/arm64/asm7.go
@@ -1015,8 +1015,9 @@ var sysInstFields = map[SpecialOperand]struct {
 // Used for padding NOOP instruction
 const OP_NOOP = 0xd503201f
 
-// align code to a certain length by padding bytes.
-func pcAlignPadLength(pc int64, alignedValue int64, ctxt *obj.Link) int {
+// pcAlignPadLength returns the number of bytes required to align pc to alignedValue,
+// reporting an error if alignedValue is not a power of two or is out of range.
+func pcAlignPadLength(ctxt *obj.Link, pc int64, alignedValue int64) int {
 	if !((alignedValue&(alignedValue-1) == 0) && 8 <= alignedValue && alignedValue <= 2048) {
 		ctxt.Diag("alignment value of an instruction must be a power of two and in the range [8, 2048], got %d\n", alignedValue)
 	}
@@ -1075,7 +1076,7 @@ func span7(ctxt *obj.Link, cursym *obj.LSym, newprog obj.ProgAlloc) {
 			switch p.As {
 			case obj.APCALIGN:
 				alignedValue := p.From.Offset
-				m = pcAlignPadLength(pc, alignedValue, ctxt)
+				m = pcAlignPadLength(ctxt, pc, alignedValue)
 				// Update the current text symbol alignment value.
 				if int32(alignedValue) > cursym.Func().Align {
 					cursym.Func().Align = int32(alignedValue)
@@ -1150,7 +1151,7 @@ func span7(ctxt *obj.Link, cursym *obj.LSym, newprog obj.ProgAlloc) {
 				switch p.As {
 				case obj.APCALIGN:
 					alignedValue := p.From.Offset
-					m = pcAlignPadLength(pc, alignedValue, ctxt)
+					m = pcAlignPadLength(ctxt, pc, alignedValue)
 					break
 				case obj.ANOP, obj.AFUNCDATA, obj.APCDATA:
 					continue
@@ -1183,7 +1184,7 @@ func span7(ctxt *obj.Link, cursym *obj.LSym, newprog obj.ProgAlloc) {
 		}
 		if p.As == obj.APCALIGN {
 			alignedValue := p.From.Offset
-			v := pcAlignPadLength(p.Pc, alignedValue, c.ctxt)
+			v := pcAlignPadLength(c.ctxt, p.Pc, alignedValue)
 			for i = 0; i < int(v/4); i++ {
 				// emit ANOOP instruction by the padding size
 				c.ctxt.Arch.ByteOrder.PutUint32(bp, OP_NOOP)