Commit 0cd8faf7 authored by Josh Bleecher Snyder's avatar Josh Bleecher Snyder

cmd/internal/obj: add opcode space safety check

This CL adds a safety mechanism
for changing the number of opcodes
available per architecture.

A subsequent CL will actually make the change.

Change-Id: I6332ed5514f2f153c54d11b7da0cc8a6be1c8066
Reviewed-on: https://go-review.googlesource.com/24222
Run-TryBot: Josh Bleecher Snyder <josharian@gmail.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: default avatarBrad Fitzpatrick <bradfitz@golang.org>
parent 496174e3
......@@ -308,7 +308,8 @@ const (
ABaseMIPS64
ABaseS390X
AMask = 1<<12 - 1 // AND with this to use the opcode as an array index.
AllowedOpCodes = 1 << 12 // The number of opcodes available for any given architecture.
AMask = AllowedOpCodes - 1 // AND with this to use the opcode as an array index.
)
// An LSym is the sort of symbol that is written to an object file.
......
......@@ -462,6 +462,9 @@ var aSpace []opSet
// RegisterOpcode binds a list of instruction names
// to a given instruction number range.
func RegisterOpcode(lo As, Anames []string) {
if len(Anames) > AllowedOpCodes {
panic(fmt.Sprintf("too many instructions, have %d max %d", len(Anames), AllowedOpCodes))
}
aSpace = append(aSpace, opSet{lo, Anames})
}
......
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