381 lines
15 KiB
Go
381 lines
15 KiB
Go
// Copyright 2013 The Go Authors. All rights reserved.
|
||
// Use of this source code is governed by a BSD-style
|
||
// license that can be found in the LICENSE file.
|
||
|
||
package pointer
|
||
|
||
// This package defines the treatment of intrinsics, i.e. library
|
||
// functions requiring special analytical treatment.
|
||
//
|
||
// Most of these are C or assembly functions, but even some Go
|
||
// functions require may special treatment if the analysis completely
|
||
// replaces the implementation of an API such as reflection.
|
||
|
||
// TODO(adonovan): support a means of writing analytic summaries in
|
||
// the target code, so that users can summarise the effects of their
|
||
// own C functions using a snippet of Go.
|
||
|
||
import (
|
||
"fmt"
|
||
|
||
"llvm.org/llgo/third_party/gotools/go/ssa"
|
||
"llvm.org/llgo/third_party/gotools/go/types"
|
||
)
|
||
|
||
// Instances of 'intrinsic' generate analysis constraints for calls to
|
||
// intrinsic functions.
|
||
// Implementations may exploit information from the calling site
|
||
// via cgn.callersite; for shared contours this is nil.
|
||
type intrinsic func(a *analysis, cgn *cgnode)
|
||
|
||
// Initialized in explicit init() to defeat (spurious) initialization
|
||
// cycle error.
|
||
var intrinsicsByName = make(map[string]intrinsic)
|
||
|
||
func init() {
|
||
// Key strings are from Function.String().
|
||
// That little dot ۰ is an Arabic zero numeral (U+06F0),
|
||
// categories [Nd].
|
||
for name, fn := range map[string]intrinsic{
|
||
// Other packages.
|
||
"bytes.Equal": ext۰NoEffect,
|
||
"bytes.IndexByte": ext۰NoEffect,
|
||
"crypto/aes.decryptBlockAsm": ext۰NoEffect,
|
||
"crypto/aes.encryptBlockAsm": ext۰NoEffect,
|
||
"crypto/aes.expandKeyAsm": ext۰NoEffect,
|
||
"crypto/aes.hasAsm": ext۰NoEffect,
|
||
"crypto/md5.block": ext۰NoEffect,
|
||
"crypto/rc4.xorKeyStream": ext۰NoEffect,
|
||
"crypto/sha1.block": ext۰NoEffect,
|
||
"crypto/sha256.block": ext۰NoEffect,
|
||
"hash/crc32.castagnoliSSE42": ext۰NoEffect,
|
||
"hash/crc32.haveSSE42": ext۰NoEffect,
|
||
"math.Abs": ext۰NoEffect,
|
||
"math.Acos": ext۰NoEffect,
|
||
"math.Asin": ext۰NoEffect,
|
||
"math.Atan": ext۰NoEffect,
|
||
"math.Atan2": ext۰NoEffect,
|
||
"math.Ceil": ext۰NoEffect,
|
||
"math.Cos": ext۰NoEffect,
|
||
"math.Dim": ext۰NoEffect,
|
||
"math.Exp": ext۰NoEffect,
|
||
"math.Exp2": ext۰NoEffect,
|
||
"math.Expm1": ext۰NoEffect,
|
||
"math.Float32bits": ext۰NoEffect,
|
||
"math.Float32frombits": ext۰NoEffect,
|
||
"math.Float64bits": ext۰NoEffect,
|
||
"math.Float64frombits": ext۰NoEffect,
|
||
"math.Floor": ext۰NoEffect,
|
||
"math.Frexp": ext۰NoEffect,
|
||
"math.Hypot": ext۰NoEffect,
|
||
"math.Ldexp": ext۰NoEffect,
|
||
"math.Log": ext۰NoEffect,
|
||
"math.Log10": ext۰NoEffect,
|
||
"math.Log1p": ext۰NoEffect,
|
||
"math.Log2": ext۰NoEffect,
|
||
"math.Max": ext۰NoEffect,
|
||
"math.Min": ext۰NoEffect,
|
||
"math.Mod": ext۰NoEffect,
|
||
"math.Modf": ext۰NoEffect,
|
||
"math.Remainder": ext۰NoEffect,
|
||
"math.Sin": ext۰NoEffect,
|
||
"math.Sincos": ext۰NoEffect,
|
||
"math.Sqrt": ext۰NoEffect,
|
||
"math.Tan": ext۰NoEffect,
|
||
"math.Trunc": ext۰NoEffect,
|
||
"math/big.addMulVVW": ext۰NoEffect,
|
||
"math/big.addVV": ext۰NoEffect,
|
||
"math/big.addVW": ext۰NoEffect,
|
||
"math/big.bitLen": ext۰NoEffect,
|
||
"math/big.divWVW": ext۰NoEffect,
|
||
"math/big.divWW": ext۰NoEffect,
|
||
"math/big.mulAddVWW": ext۰NoEffect,
|
||
"math/big.mulWW": ext۰NoEffect,
|
||
"math/big.shlVU": ext۰NoEffect,
|
||
"math/big.shrVU": ext۰NoEffect,
|
||
"math/big.subVV": ext۰NoEffect,
|
||
"math/big.subVW": ext۰NoEffect,
|
||
"net.runtime_Semacquire": ext۰NoEffect,
|
||
"net.runtime_Semrelease": ext۰NoEffect,
|
||
"net.runtime_pollClose": ext۰NoEffect,
|
||
"net.runtime_pollOpen": ext۰NoEffect,
|
||
"net.runtime_pollReset": ext۰NoEffect,
|
||
"net.runtime_pollServerInit": ext۰NoEffect,
|
||
"net.runtime_pollSetDeadline": ext۰NoEffect,
|
||
"net.runtime_pollUnblock": ext۰NoEffect,
|
||
"net.runtime_pollWait": ext۰NoEffect,
|
||
"net.runtime_pollWaitCanceled": ext۰NoEffect,
|
||
"os.epipecheck": ext۰NoEffect,
|
||
"runtime.BlockProfile": ext۰NoEffect,
|
||
"runtime.Breakpoint": ext۰NoEffect,
|
||
"runtime.CPUProfile": ext۰NoEffect, // good enough
|
||
"runtime.Caller": ext۰NoEffect,
|
||
"runtime.Callers": ext۰NoEffect, // good enough
|
||
"runtime.FuncForPC": ext۰NoEffect,
|
||
"runtime.GC": ext۰NoEffect,
|
||
"runtime.GOMAXPROCS": ext۰NoEffect,
|
||
"runtime.Goexit": ext۰NoEffect,
|
||
"runtime.GoroutineProfile": ext۰NoEffect,
|
||
"runtime.Gosched": ext۰NoEffect,
|
||
"runtime.MemProfile": ext۰NoEffect,
|
||
"runtime.NumCPU": ext۰NoEffect,
|
||
"runtime.NumGoroutine": ext۰NoEffect,
|
||
"runtime.ReadMemStats": ext۰NoEffect,
|
||
"runtime.SetBlockProfileRate": ext۰NoEffect,
|
||
"runtime.SetCPUProfileRate": ext۰NoEffect,
|
||
"runtime.SetFinalizer": ext۰runtime۰SetFinalizer,
|
||
"runtime.Stack": ext۰NoEffect,
|
||
"runtime.ThreadCreateProfile": ext۰NoEffect,
|
||
"runtime.cstringToGo": ext۰NoEffect,
|
||
"runtime.funcentry_go": ext۰NoEffect,
|
||
"runtime.funcline_go": ext۰NoEffect,
|
||
"runtime.funcname_go": ext۰NoEffect,
|
||
"runtime.getgoroot": ext۰NoEffect,
|
||
"runtime/pprof.runtime_cyclesPerSecond": ext۰NoEffect,
|
||
"strings.IndexByte": ext۰NoEffect,
|
||
"sync.runtime_Semacquire": ext۰NoEffect,
|
||
"sync.runtime_Semrelease": ext۰NoEffect,
|
||
"sync.runtime_Syncsemacquire": ext۰NoEffect,
|
||
"sync.runtime_Syncsemcheck": ext۰NoEffect,
|
||
"sync.runtime_Syncsemrelease": ext۰NoEffect,
|
||
"sync.runtime_procPin": ext۰NoEffect,
|
||
"sync.runtime_procUnpin": ext۰NoEffect,
|
||
"sync.runtime_registerPool": ext۰NoEffect,
|
||
"sync/atomic.AddInt32": ext۰NoEffect,
|
||
"sync/atomic.AddInt64": ext۰NoEffect,
|
||
"sync/atomic.AddUint32": ext۰NoEffect,
|
||
"sync/atomic.AddUint64": ext۰NoEffect,
|
||
"sync/atomic.AddUintptr": ext۰NoEffect,
|
||
"sync/atomic.CompareAndSwapInt32": ext۰NoEffect,
|
||
"sync/atomic.CompareAndSwapUint32": ext۰NoEffect,
|
||
"sync/atomic.CompareAndSwapUint64": ext۰NoEffect,
|
||
"sync/atomic.CompareAndSwapUintptr": ext۰NoEffect,
|
||
"sync/atomic.LoadInt32": ext۰NoEffect,
|
||
"sync/atomic.LoadInt64": ext۰NoEffect,
|
||
"sync/atomic.LoadPointer": ext۰NoEffect, // ignore unsafe.Pointers
|
||
"sync/atomic.LoadUint32": ext۰NoEffect,
|
||
"sync/atomic.LoadUint64": ext۰NoEffect,
|
||
"sync/atomic.LoadUintptr": ext۰NoEffect,
|
||
"sync/atomic.StoreInt32": ext۰NoEffect,
|
||
"sync/atomic.StorePointer": ext۰NoEffect, // ignore unsafe.Pointers
|
||
"sync/atomic.StoreUint32": ext۰NoEffect,
|
||
"sync/atomic.StoreUintptr": ext۰NoEffect,
|
||
"syscall.Close": ext۰NoEffect,
|
||
"syscall.Exit": ext۰NoEffect,
|
||
"syscall.Getpid": ext۰NoEffect,
|
||
"syscall.Getwd": ext۰NoEffect,
|
||
"syscall.Kill": ext۰NoEffect,
|
||
"syscall.RawSyscall": ext۰NoEffect,
|
||
"syscall.RawSyscall6": ext۰NoEffect,
|
||
"syscall.Syscall": ext۰NoEffect,
|
||
"syscall.Syscall6": ext۰NoEffect,
|
||
"syscall.runtime_AfterFork": ext۰NoEffect,
|
||
"syscall.runtime_BeforeFork": ext۰NoEffect,
|
||
"syscall.setenv_c": ext۰NoEffect,
|
||
"time.Sleep": ext۰NoEffect,
|
||
"time.now": ext۰NoEffect,
|
||
"time.startTimer": ext۰time۰startTimer,
|
||
"time.stopTimer": ext۰NoEffect,
|
||
} {
|
||
intrinsicsByName[name] = fn
|
||
}
|
||
}
|
||
|
||
// findIntrinsic returns the constraint generation function for an
|
||
// intrinsic function fn, or nil if the function should be handled normally.
|
||
//
|
||
func (a *analysis) findIntrinsic(fn *ssa.Function) intrinsic {
|
||
// Consult the *Function-keyed cache.
|
||
// A cached nil indicates a normal non-intrinsic function.
|
||
impl, ok := a.intrinsics[fn]
|
||
if !ok {
|
||
impl = intrinsicsByName[fn.String()] // may be nil
|
||
|
||
if a.isReflect(fn) {
|
||
if !a.config.Reflection {
|
||
impl = ext۰NoEffect // reflection disabled
|
||
} else if impl == nil {
|
||
// Ensure all "reflect" code is treated intrinsically.
|
||
impl = ext۰NotYetImplemented
|
||
}
|
||
}
|
||
|
||
a.intrinsics[fn] = impl
|
||
}
|
||
return impl
|
||
}
|
||
|
||
// isReflect reports whether fn belongs to the "reflect" package.
|
||
func (a *analysis) isReflect(fn *ssa.Function) bool {
|
||
if a.reflectValueObj == nil {
|
||
return false // "reflect" package not loaded
|
||
}
|
||
reflectPackage := a.reflectValueObj.Pkg()
|
||
if fn.Pkg != nil && fn.Pkg.Object == reflectPackage {
|
||
return true
|
||
}
|
||
// Synthetic wrappers have a nil Pkg, so they slip through the
|
||
// previous check. Check the receiver package.
|
||
// TODO(adonovan): should synthetic wrappers have a non-nil Pkg?
|
||
if recv := fn.Signature.Recv(); recv != nil {
|
||
if named, ok := deref(recv.Type()).(*types.Named); ok {
|
||
if named.Obj().Pkg() == reflectPackage {
|
||
return true // e.g. wrapper of (reflect.Value).f
|
||
}
|
||
}
|
||
}
|
||
return false
|
||
}
|
||
|
||
// A trivial intrinsic suitable for any function that does not:
|
||
// 1) induce aliases between its arguments or any global variables;
|
||
// 2) call any functions; or
|
||
// 3) create any labels.
|
||
//
|
||
// Many intrinsics (such as CompareAndSwapInt32) have a fourth kind of
|
||
// effect: loading or storing through a pointer. Though these could
|
||
// be significant, we deliberately ignore them because they are
|
||
// generally not worth the effort.
|
||
//
|
||
// We sometimes violate condition #3 if the function creates only
|
||
// non-function labels, as the control-flow graph is still sound.
|
||
//
|
||
func ext۰NoEffect(a *analysis, cgn *cgnode) {}
|
||
|
||
func ext۰NotYetImplemented(a *analysis, cgn *cgnode) {
|
||
fn := cgn.fn
|
||
a.warnf(fn.Pos(), "unsound: intrinsic treatment of %s not yet implemented", fn)
|
||
}
|
||
|
||
// ---------- func runtime.SetFinalizer(x, f interface{}) ----------
|
||
|
||
// runtime.SetFinalizer(x, f)
|
||
type runtimeSetFinalizerConstraint struct {
|
||
targets nodeid // (indirect)
|
||
f nodeid // (ptr)
|
||
x nodeid
|
||
}
|
||
|
||
func (c *runtimeSetFinalizerConstraint) ptr() nodeid { return c.f }
|
||
func (c *runtimeSetFinalizerConstraint) presolve(h *hvn) {
|
||
h.markIndirect(onodeid(c.targets), "SetFinalizer.targets")
|
||
}
|
||
func (c *runtimeSetFinalizerConstraint) renumber(mapping []nodeid) {
|
||
c.targets = mapping[c.targets]
|
||
c.f = mapping[c.f]
|
||
c.x = mapping[c.x]
|
||
}
|
||
|
||
func (c *runtimeSetFinalizerConstraint) String() string {
|
||
return fmt.Sprintf("runtime.SetFinalizer(n%d, n%d)", c.x, c.f)
|
||
}
|
||
|
||
func (c *runtimeSetFinalizerConstraint) solve(a *analysis, delta *nodeset) {
|
||
for _, fObj := range delta.AppendTo(a.deltaSpace) {
|
||
tDyn, f, indirect := a.taggedValue(nodeid(fObj))
|
||
if indirect {
|
||
// TODO(adonovan): we'll need to implement this
|
||
// when we start creating indirect tagged objects.
|
||
panic("indirect tagged object")
|
||
}
|
||
|
||
tSig, ok := tDyn.Underlying().(*types.Signature)
|
||
if !ok {
|
||
continue // not a function
|
||
}
|
||
if tSig.Recv() != nil {
|
||
panic(tSig)
|
||
}
|
||
if tSig.Params().Len() != 1 {
|
||
continue // not a unary function
|
||
}
|
||
|
||
// Extract x to tmp.
|
||
tx := tSig.Params().At(0).Type()
|
||
tmp := a.addNodes(tx, "SetFinalizer.tmp")
|
||
a.typeAssert(tx, tmp, c.x, false)
|
||
|
||
// Call f(tmp).
|
||
a.store(f, tmp, 1, a.sizeof(tx))
|
||
|
||
// Add dynamic call target.
|
||
if a.onlineCopy(c.targets, f) {
|
||
a.addWork(c.targets)
|
||
}
|
||
}
|
||
}
|
||
|
||
func ext۰runtime۰SetFinalizer(a *analysis, cgn *cgnode) {
|
||
// This is the shared contour, used for dynamic calls.
|
||
targets := a.addOneNode(tInvalid, "SetFinalizer.targets", nil)
|
||
cgn.sites = append(cgn.sites, &callsite{targets: targets})
|
||
params := a.funcParams(cgn.obj)
|
||
a.addConstraint(&runtimeSetFinalizerConstraint{
|
||
targets: targets,
|
||
x: params,
|
||
f: params + 1,
|
||
})
|
||
}
|
||
|
||
// ---------- func time.startTimer(t *runtimeTimer) ----------
|
||
|
||
// time.StartTimer(t)
|
||
type timeStartTimerConstraint struct {
|
||
targets nodeid // (indirect)
|
||
t nodeid // (ptr)
|
||
}
|
||
|
||
func (c *timeStartTimerConstraint) ptr() nodeid { return c.t }
|
||
func (c *timeStartTimerConstraint) presolve(h *hvn) {
|
||
h.markIndirect(onodeid(c.targets), "StartTimer.targets")
|
||
}
|
||
func (c *timeStartTimerConstraint) renumber(mapping []nodeid) {
|
||
c.targets = mapping[c.targets]
|
||
c.t = mapping[c.t]
|
||
}
|
||
|
||
func (c *timeStartTimerConstraint) String() string {
|
||
return fmt.Sprintf("time.startTimer(n%d)", c.t)
|
||
}
|
||
|
||
func (c *timeStartTimerConstraint) solve(a *analysis, delta *nodeset) {
|
||
for _, tObj := range delta.AppendTo(a.deltaSpace) {
|
||
t := nodeid(tObj)
|
||
|
||
// We model startTimer as if it was defined thus:
|
||
// func startTimer(t *runtimeTimer) { t.f(t.arg) }
|
||
|
||
// We hard-code the field offsets of time.runtimeTimer:
|
||
// type runtimeTimer struct {
|
||
// 0 __identity__
|
||
// 1 i int32
|
||
// 2 when int64
|
||
// 3 period int64
|
||
// 4 f func(int64, interface{})
|
||
// 5 arg interface{}
|
||
// }
|
||
f := t + 4
|
||
arg := t + 5
|
||
|
||
// store t.arg to t.f.params[0]
|
||
// (offset 1 => skip identity)
|
||
a.store(f, arg, 1, 1)
|
||
|
||
// Add dynamic call target.
|
||
if a.onlineCopy(c.targets, f) {
|
||
a.addWork(c.targets)
|
||
}
|
||
}
|
||
}
|
||
|
||
func ext۰time۰startTimer(a *analysis, cgn *cgnode) {
|
||
// This is the shared contour, used for dynamic calls.
|
||
targets := a.addOneNode(tInvalid, "startTimer.targets", nil)
|
||
cgn.sites = append(cgn.sites, &callsite{targets: targets})
|
||
params := a.funcParams(cgn.obj)
|
||
a.addConstraint(&timeStartTimerConstraint{
|
||
targets: targets,
|
||
t: params,
|
||
})
|
||
}
|