cmd/compile: add DWARF register mappings for ARM64.

Add DWARF register mappings for ARM64, so that that arch will become
usable with "-dwarflocationlists". [NB: I've plugged in a set of
numbers from the doc, but this will require additional manual testing.]

Change-Id: Id9aa63857bc8b4f5c825f49274101cf372e9e856
Reviewed-on: https://go-review.googlesource.com/82515Reviewed-by: Heschi Kreinick <heschi@google.com>

src/cmd/internal/obj/arm64/a.out.go

@@ -261,6 +261,109 @@ const (
 	FREGEXT = REG_F26 // first external register
 )
 
+// http://infocenter.arm.com/help/topic/com.arm.doc.ecm0665627/abi_sve_aadwarf_100985_0000_00_en.pdf
+var ARM64DWARFRegisters = map[int16]int16{
+	REG_R0:  0,
+	REG_R1:  1,
+	REG_R2:  2,
+	REG_R3:  3,
+	REG_R4:  4,
+	REG_R5:  5,
+	REG_R6:  6,
+	REG_R7:  7,
+	REG_R8:  8,
+	REG_R9:  9,
+	REG_R10: 10,
+	REG_R11: 11,
+	REG_R12: 12,
+	REG_R13: 13,
+	REG_R14: 14,
+	REG_R15: 15,
+	REG_R16: 16,
+	REG_R17: 17,
+	REG_R18: 18,
+	REG_R19: 19,
+	REG_R20: 20,
+	REG_R21: 21,
+	REG_R22: 22,
+	REG_R23: 23,
+	REG_R24: 24,
+	REG_R25: 25,
+	REG_R26: 26,
+	REG_R27: 27,
+	REG_R28: 28,
+	REG_R29: 29,
+	REG_R30: 30,
+
+	// floating point
+	REG_F0:  64,
+	REG_F1:  65,
+	REG_F2:  66,
+	REG_F3:  67,
+	REG_F4:  68,
+	REG_F5:  69,
+	REG_F6:  70,
+	REG_F7:  71,
+	REG_F8:  72,
+	REG_F9:  73,
+	REG_F10: 74,
+	REG_F11: 75,
+	REG_F12: 76,
+	REG_F13: 77,
+	REG_F14: 78,
+	REG_F15: 79,
+	REG_F16: 80,
+	REG_F17: 81,
+	REG_F18: 82,
+	REG_F19: 83,
+	REG_F20: 84,
+	REG_F21: 85,
+	REG_F22: 86,
+	REG_F23: 87,
+	REG_F24: 88,
+	REG_F25: 89,
+	REG_F26: 90,
+	REG_F27: 91,
+	REG_F28: 92,
+	REG_F29: 93,
+	REG_F30: 94,
+	REG_F31: 95,
+
+	// SIMD
+	REG_V0:  64,
+	REG_V1:  65,
+	REG_V2:  66,
+	REG_V3:  67,
+	REG_V4:  68,
+	REG_V5:  69,
+	REG_V6:  70,
+	REG_V7:  71,
+	REG_V8:  72,
+	REG_V9:  73,
+	REG_V10: 74,
+	REG_V11: 75,
+	REG_V12: 76,
+	REG_V13: 77,
+	REG_V14: 78,
+	REG_V15: 79,
+	REG_V16: 80,
+	REG_V17: 81,
+	REG_V18: 82,
+	REG_V19: 83,
+	REG_V20: 84,
+	REG_V21: 85,
+	REG_V22: 86,
+	REG_V23: 87,
+	REG_V24: 88,
+	REG_V25: 89,
+	REG_V26: 90,
+	REG_V27: 91,
+	REG_V28: 92,
+	REG_V29: 93,
+	REG_V30: 94,
+	REG_V31: 95,
+}
+
 const (
 	BIG = 2048 - 8
 )

src/cmd/internal/obj/arm64/obj7.go

@@ -838,10 +838,11 @@ var unaryDst = map[obj.As]bool{
 }
 
 var Linkarm64 = obj.LinkArch{
-	Arch:       sys.ArchARM64,
-	Init:       buildop,
-	Preprocess: preprocess,
-	Assemble:   span7,
-	Progedit:   progedit,
-	UnaryDst:   unaryDst,
+	Arch:           sys.ArchARM64,
+	Init:           buildop,
+	Preprocess:     preprocess,
+	Assemble:       span7,
+	Progedit:       progedit,
+	UnaryDst:       unaryDst,
+	DWARFRegisters: ARM64DWARFRegisters,
 }