pkg/ifuzz/iset: rename ifuzzimpl to iset

ifuzzimpl is too lenghty and too clumsy on my taste
(nm/vmimpl worked better b/c it's shorter and used less).
I've tried to come up with something shorter and nicer.
We could use "insn" as a common name for "instruction" in ifuzz,
but it's a commonly used name already so would cause lots of conflicts.
"iset" is somewhat descriptive, short and nice.

1 files changed, 102 insertions, 0 deletions

diff --git a/pkg/ifuzz/iset/iset.go b/pkg/ifuzz/iset/iset.go
new file mode 100644
index 000000000..46c42537d
--- /dev/null
+++ b/pkg/ifuzz/iset/iset.go
@@ -0,0 +1,102 @@
+// Copyright 2017 syzkaller project authors. All rights reserved.
+// Use of this source code is governed by Apache 2 LICENSE that can be found in the LICENSE file.
+
+// Package iset ("instruction set") provides base and helper types for ifuzz arch implementations.
+package iset
+
+import (
+	"math/rand"
+)
+
+const (
+	ArchX86     = "x86"
+	ArchPowerPC = "powerpc"
+)
+
+var Arches = make(map[string]InsnSet)
+
+type (
+	Mode int
+	Type int
+)
+
+type Insn interface {
+	Info() (name string, mode Mode, pseudo, priv bool)
+	Encode(cfg *Config, r *rand.Rand) []byte
+}
+
+type InsnSet interface {
+	GetInsns(mode Mode, typ Type) []Insn
+	Decode(mode Mode, text []byte) (int, error)
+	DecodeExt(mode Mode, text []byte) (int, error) // XED, to keep ifuzz_test happy
+}
+
+type Config struct {
+	Arch       string
+	Len        int         // number of instructions to generate
+	Mode       Mode        // one of ModeXXX
+	Priv       bool        // generate CPL=0 instructions (x86), HV/!PR mode (PPC)
+	Exec       bool        // generate instructions sequences interesting for execution
+	MemRegions []MemRegion // generated instructions will reference these regions
+}
+
+type MemRegion struct {
+	Start uint64
+	Size  uint64
+}
+
+const (
+	ModeLong64 Mode = iota
+	ModeProt32
+	ModeProt16
+	ModeReal16
+	ModeLast
+)
+
+const (
+	TypeExec Type = iota
+	TypePriv
+	TypeUser
+	TypeAll
+	TypeLast
+)
+
+var SpecialNumbers = [...]uint64{0, 1 << 15, 1 << 16, 1 << 31, 1 << 32, 1 << 47, 1 << 47, 1 << 63}
+
+type ModeInsns [ModeLast][TypeLast][]Insn
+
+func (modeInsns *ModeInsns) Add(insn Insn) {
+	_, mode, pseudo, priv := insn.Info()
+	for m := Mode(0); m < ModeLast; m++ {
+		if mode&(1<<uint(m)) == 0 {
+			continue
+		}
+		set := &modeInsns[m]
+		if pseudo {
+			set[TypeExec] = append(set[TypeExec], insn)
+		} else if priv {
+			set[TypePriv] = append(set[TypePriv], insn)
+			set[TypeAll] = append(set[TypeAll], insn)
+		} else {
+			set[TypeUser] = append(set[TypeUser], insn)
+			set[TypeAll] = append(set[TypeAll], insn)
+		}
+	}
+}
+
+func (cfg *Config) IsCompatible(insn Insn) bool {
+	_, mode, pseudo, priv := insn.Info()
+	if cfg.Mode < 0 || cfg.Mode >= ModeLast {
+		panic("bad mode")
+	}
+	if priv && !cfg.Priv {
+		return false
+	}
+	if pseudo && !cfg.Exec {
+		return false
+	}
+	if mode&(1<<uint(cfg.Mode)) == 0 {
+		return false
+	}
+	return true
+}