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compiler, runtime: panic on uncomparable map key, even if map is empty

Browse Source 
This ports https://golang.org/cl/155918 from the master repo.
    
        runtime: panic on uncomparable map key, even if map is empty
    
        Reorg map flags a bit so we don't need any extra space for the extra flag.
    
    This is a pre-req for updating libgo to the Go 1.12beta2 release.
    
    Reviewed-on: https://go-review.googlesource.com/c/157858

From-SVN: r267950
This commit is contained in:
Ian Lance Taylor 2019-01-15 20:32:39 +00:00
parent a81a6d5836
commit 6a0c8e77f2
6 changed files with 170 additions and 84 deletions
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2
gcc/go/gofrontend/MERGE
View File

@ -1,4 +1,4 @@
0d64279c01a37b2579c0c62ca4f2c3e3f81de07c
87005025fcd0d7e7908b3aae7062b52cb80eb0f3
The first line of this file holds the git revision number of the last
merge done from the gofrontend repository.

62
gcc/go/gofrontend/types.cc
View File

@ -5839,6 +5839,25 @@ Struct_type::do_needs_key_update()
return false;
}
// Return whether computing the hash value of an instance of this
// struct type might panic.
bool
Struct_type::do_hash_might_panic()
{
const Struct_field_list* fields = this->fields_;
if (fields == NULL)
return false;
for (Struct_field_list::const_iterator pf = fields->begin();
pf != fields->end();
++pf)
{
if (pf->type()->hash_might_panic())
return true;
}
return false;
}
// Return whether this struct type is permitted to be in the heap.
bool
@ -7979,21 +7998,18 @@ Map_type::make_map_type_descriptor_type()
Type* ptdt = Type::make_type_descriptor_ptr_type();
Type* uint8_type = Type::lookup_integer_type("uint8");
Type* uint16_type = Type::lookup_integer_type("uint16");
Type* bool_type = Type::lookup_bool_type();
Type* uint32_type = Type::lookup_integer_type("uint32");
Struct_type* sf =
Type::make_builtin_struct_type(11,
Type::make_builtin_struct_type(8,
"", tdt,
"key", ptdt,
"elem", ptdt,
"bucket", ptdt,
"keysize", uint8_type,
"indirectkey", bool_type,
"valuesize", uint8_type,
"indirectvalue", bool_type,
"bucketsize", uint16_type,
"reflexivekey", bool_type,
"needkeyupdate", bool_type);
"flags", uint32_type);
ret = Type::make_builtin_named_type("MapType", sf);
}
@ -8011,6 +8027,7 @@ Map_type::do_type_descriptor(Gogo* gogo, Named_type* name)
Type* mtdt = Map_type::make_map_type_descriptor_type();
Type* uint8_type = Type::lookup_integer_type("uint8");
Type* uint16_type = Type::lookup_integer_type("uint16");
Type* uint32_type = Type::lookup_integer_type("uint32");
int64_t keysize;
if (!this->key_type_->backend_type_size(gogo, &keysize))
@ -8077,11 +8094,6 @@ Map_type::do_type_descriptor(Gogo* gogo, Named_type* name)
else
vals->push_back(Expression::make_integer_int64(keysize, uint8_type, bloc));
++p;
go_assert(p->is_field_name("indirectkey"));
vals->push_back(Expression::make_boolean(keysize > Map_type::max_key_size,
bloc));
++p;
go_assert(p->is_field_name("valuesize"));
if (valsize > Map_type::max_val_size)
@ -8089,25 +8101,27 @@ Map_type::do_type_descriptor(Gogo* gogo, Named_type* name)
else
vals->push_back(Expression::make_integer_int64(valsize, uint8_type, bloc));
++p;
go_assert(p->is_field_name("indirectvalue"));
vals->push_back(Expression::make_boolean(valsize > Map_type::max_val_size,
bloc));
++p;
go_assert(p->is_field_name("bucketsize"));
vals->push_back(Expression::make_integer_int64(bucketsize, uint16_type,
bloc));
++p;
go_assert(p->is_field_name("reflexivekey"));
vals->push_back(Expression::make_boolean(this->key_type_->is_reflexive(),
bloc));
++p;
go_assert(p->is_field_name("needkeyupdate"));
vals->push_back(Expression::make_boolean(this->key_type_->needs_key_update(),
bloc));
go_assert(p->is_field_name("flags"));
// As with the other fields, the flag bits must match the reflect
// and runtime packages.
unsigned long flags = 0;
if (keysize > Map_type::max_key_size)
flags |= 1;
if (valsize > Map_type::max_val_size)
flags |= 2;
if (this->key_type_->is_reflexive())
flags |= 4;
if (this->key_type_->needs_key_update())
flags |= 8;
if (this->key_type_->hash_might_panic())
flags |= 16;
vals->push_back(Expression::make_integer_ul(flags, uint32_type, bloc));
++p;
go_assert(p == fields->end());

22
gcc/go/gofrontend/types.h
View File

@ -635,6 +635,12 @@ class Type
needs_key_update()
{ return this->do_needs_key_update(); }
// Return whether the hash function of this type might panic. This
// is only called for types used as a key in a map type.
bool
hash_might_panic()
{ return this->do_hash_might_panic(); }
// Whether the type is permitted in the heap.
bool
in_heap()
@ -1073,6 +1079,10 @@ class Type
do_needs_key_update()
{ return false; }
virtual bool
do_hash_might_panic()
{ return false; }
virtual bool
do_in_heap()
{ return true; }
@ -2600,6 +2610,9 @@ class Struct_type : public Type
bool
do_needs_key_update();
bool
do_hash_might_panic();
bool
do_in_heap();
@ -2778,6 +2791,10 @@ class Array_type : public Type
do_needs_key_update()
{ return this->element_type_->needs_key_update(); }
bool
do_hash_might_panic()
{ return this->length_ != NULL && this->element_type_->hash_might_panic(); }
bool
do_in_heap()
{ return this->length_ == NULL || this->element_type_->in_heap(); }
@ -3170,6 +3187,11 @@ class Interface_type : public Type
do_needs_key_update()
{ return true; }
// Hashing an unhashable type stored in an interface might panic.
bool
do_hash_might_panic()
{ return true; }
unsigned int
do_hash_for_method(Gogo*, int) const;

58
libgo/go/reflect/type.go
View File

@ -347,16 +347,13 @@ type interfaceType struct {
// mapType represents a map type.
type mapType struct {
rtype
key *rtype // map key type
elem *rtype // map element (value) type
bucket *rtype // internal bucket structure
keysize uint8 // size of key slot
indirectkey uint8 // store ptr to key instead of key itself
valuesize uint8 // size of value slot
indirectvalue uint8 // store ptr to value instead of value itself
bucketsize uint16 // size of bucket
reflexivekey bool // true if k==k for all keys
needkeyupdate bool // true if we need to update key on an overwrite
key *rtype // map key type
elem *rtype // map element (value) type
bucket *rtype // internal bucket structure
keysize uint8 // size of key slot
valuesize uint8 // size of value slot
bucketsize uint16 // size of bucket
flags uint32
}
// ptrType represents a pointer type.
@ -1506,6 +1503,8 @@ func MapOf(key, elem Type) Type {
s := "map[" + *ktyp.string + "]" + *etyp.string
// Make a map type.
// Note: flag values must match those used in the TMAP case
// in ../cmd/compile/internal/gc/reflect.go:dtypesym.
var imap interface{} = (map[unsafe.Pointer]unsafe.Pointer)(nil)
mt := **(**mapType)(unsafe.Pointer(&imap))
mt.string = &s
@ -1520,23 +1519,29 @@ func MapOf(key, elem Type) Type {
mt.ptrToThis = nil
mt.bucket = bucketOf(ktyp, etyp)
mt.flags = 0
if ktyp.size > maxKeySize {
mt.keysize = uint8(ptrSize)
mt.indirectkey = 1
mt.flags |= 1 // indirect key
} else {
mt.keysize = uint8(ktyp.size)
mt.indirectkey = 0
}
if etyp.size > maxValSize {
mt.valuesize = uint8(ptrSize)
mt.indirectvalue = 1
mt.flags |= 2 // indirect value
} else {
mt.valuesize = uint8(etyp.size)
mt.indirectvalue = 0
}
mt.bucketsize = uint16(mt.bucket.size)
mt.reflexivekey = isReflexive(ktyp)
mt.needkeyupdate = needKeyUpdate(ktyp)
if isReflexive(ktyp) {
mt.flags |= 4
}
if needKeyUpdate(ktyp) {
mt.flags |= 8
}
if hashMightPanic(ktyp) {
mt.flags |= 16
}
// Canonicalize before storing in lookupCache
ti := toType(&mt.rtype)
@ -1715,6 +1720,27 @@ func needKeyUpdate(t *rtype) bool {
}
}
// hashMightPanic reports whether the hash of a map key of type t might panic.
func hashMightPanic(t *rtype) bool {
switch t.Kind() {
case Interface:
return true
case Array:
tt := (*arrayType)(unsafe.Pointer(t))
return hashMightPanic(tt.elem)
case Struct:
tt := (*structType)(unsafe.Pointer(t))
for _, f := range tt.fields {
if hashMightPanic(f.typ) {
return true
}
}
return false
default:
return false
}
}
// Make sure these routines stay in sync with ../../runtime/map.go!
// These types exist only for GC, so we only fill out GC relevant info.
// Currently, that's just size and the GC program. We also fill in string

73
libgo/go/runtime/map.go
View File

@ -414,14 +414,17 @@ func mapaccess1(t *maptype, h *hmap, key unsafe.Pointer) unsafe.Pointer {
if msanenabled && h != nil {
msanread(key, t.key.size)
}
hashfn := t.key.hashfn
equalfn := t.key.equalfn
if h == nil || h.count == 0 {
if t.hashMightPanic() {
hashfn(key, 0) // see issue 23734
}
return unsafe.Pointer(&zeroVal[0])
}
if h.flags&hashWriting != 0 {
throw("concurrent map read and map write")
}
hashfn := t.key.hashfn
equalfn := t.key.equalfn
hash := hashfn(key, uintptr(h.hash0))
m := bucketMask(h.B)
b := (*bmap)(add(h.buckets, (hash&m)*uintptr(t.bucketsize)))
@ -442,12 +445,12 @@ func mapaccess1(t *maptype, h *hmap, key unsafe.Pointer) unsafe.Pointer {
continue
}
k := add(unsafe.Pointer(b), dataOffset+i*uintptr(t.keysize))
if t.indirectkey {
if t.indirectkey() {
k = *((*unsafe.Pointer)(k))
}
if equalfn(key, k) {
v := add(unsafe.Pointer(b), dataOffset+bucketCnt*uintptr(t.keysize)+i*uintptr(t.valuesize))
if t.indirectvalue {
if t.indirectvalue() {
v = *((*unsafe.Pointer)(v))
}
return v
@ -472,14 +475,17 @@ func mapaccess2(t *maptype, h *hmap, key unsafe.Pointer) (unsafe.Pointer, bool)
if msanenabled && h != nil {
msanread(key, t.key.size)
}
hashfn := t.key.hashfn
equalfn := t.key.equalfn
if h == nil || h.count == 0 {
if t.hashMightPanic() {
hashfn(key, 0) // see issue 23734
}
return unsafe.Pointer(&zeroVal[0]), false
}
if h.flags&hashWriting != 0 {
throw("concurrent map read and map write")
}
hashfn := t.key.hashfn
equalfn := t.key.equalfn
hash := hashfn(key, uintptr(h.hash0))
m := bucketMask(h.B)
b := (*bmap)(unsafe.Pointer(uintptr(h.buckets) + (hash&m)*uintptr(t.bucketsize)))
@ -500,12 +506,12 @@ func mapaccess2(t *maptype, h *hmap, key unsafe.Pointer) (unsafe.Pointer, bool)
continue
}
k := add(unsafe.Pointer(b), dataOffset+i*uintptr(t.keysize))
if t.indirectkey {
if t.indirectkey() {
k = *((*unsafe.Pointer)(k))
}
if equalfn(key, k) {
v := add(unsafe.Pointer(b), dataOffset+bucketCnt*uintptr(t.keysize)+i*uintptr(t.valuesize))
if t.indirectvalue {
if t.indirectvalue() {
v = *((*unsafe.Pointer)(v))
}
return v, true
@ -547,12 +553,12 @@ func mapaccessK(t *maptype, h *hmap, key unsafe.Pointer) (unsafe.Pointer, unsafe
continue
}
k := add(unsafe.Pointer(b), dataOffset+i*uintptr(t.keysize))
if t.indirectkey {
if t.indirectkey() {
k = *((*unsafe.Pointer)(k))
}
if equalfn(key, k) {
v := add(unsafe.Pointer(b), dataOffset+bucketCnt*uintptr(t.keysize)+i*uintptr(t.valuesize))
if t.indirectvalue {
if t.indirectvalue() {
v = *((*unsafe.Pointer)(v))
}
return k, v
@ -634,14 +640,14 @@ again:
continue
}
k := add(unsafe.Pointer(b), dataOffset+i*uintptr(t.keysize))
if t.indirectkey {
if t.indirectkey() {
k = *((*unsafe.Pointer)(k))
}
if !equalfn(key, k) {
continue
}
// already have a mapping for key. Update it.
if t.needkeyupdate {
if t.needkeyupdate() {
typedmemmove(t.key, k, key)
}
val = add(unsafe.Pointer(b), dataOffset+bucketCnt*uintptr(t.keysize)+i*uintptr(t.valuesize))
@ -672,12 +678,12 @@ again:
}
// store new key/value at insert position
if t.indirectkey {
if t.indirectkey() {
kmem := newobject(t.key)
*(*unsafe.Pointer)(insertk) = kmem
insertk = kmem
}
if t.indirectvalue {
if t.indirectvalue() {
vmem := newobject(t.elem)
*(*unsafe.Pointer)(val) = vmem
}
@ -690,7 +696,7 @@ done:
throw("concurrent map writes")
}
h.flags &^= hashWriting
if t.indirectvalue {
if t.indirectvalue() {
val = *((*unsafe.Pointer)(val))
}
return val
@ -706,15 +712,18 @@ func mapdelete(t *maptype, h *hmap, key unsafe.Pointer) {
if msanenabled && h != nil {
msanread(key, t.key.size)
}
hashfn := t.key.hashfn
equalfn := t.key.equalfn
if h == nil || h.count == 0 {
if t.hashMightPanic() {
hashfn(key, 0) // see issue 23734
}
return
}
if h.flags&hashWriting != 0 {
throw("concurrent map writes")
}
hashfn := t.key.hashfn
equalfn := t.key.equalfn
hash := hashfn(key, uintptr(h.hash0))
// Set hashWriting after calling alg.hash, since alg.hash may panic,
@ -735,20 +744,20 @@ search:
}
k := add(unsafe.Pointer(b), dataOffset+i*uintptr(t.keysize))
k2 := k
if t.indirectkey {
if t.indirectkey() {
k2 = *((*unsafe.Pointer)(k2))
}
if !equalfn(key, k2) {
continue
}
// Only clear key if there are pointers in it.
if t.indirectkey {
if t.indirectkey() {
*(*unsafe.Pointer)(k) = nil
} else if t.key.kind&kindNoPointers == 0 {
memclrHasPointers(k, t.key.size)
}
v := add(unsafe.Pointer(b), dataOffset+bucketCnt*uintptr(t.keysize)+i*uintptr(t.valuesize))
if t.indirectvalue {
if t.indirectvalue() {
*(*unsafe.Pointer)(v) = nil
} else if t.elem.kind&kindNoPointers == 0 {
memclrHasPointers(v, t.elem.size)
@ -894,7 +903,7 @@ next:
continue
}
k := add(unsafe.Pointer(b), dataOffset+uintptr(offi)*uintptr(t.keysize))
if t.indirectkey {
if t.indirectkey() {
k = *((*unsafe.Pointer)(k))
}
v := add(unsafe.Pointer(b), dataOffset+bucketCnt*uintptr(t.keysize)+uintptr(offi)*uintptr(t.valuesize))
@ -906,7 +915,7 @@ next:
// through the oldbucket, skipping any keys that will go
// to the other new bucket (each oldbucket expands to two
// buckets during a grow).
if t.reflexivekey || equalfn(k, k) {
if t.reflexivekey() || equalfn(k, k) {
// If the item in the oldbucket is not destined for
// the current new bucket in the iteration, skip it.
hash := hashfn(k, uintptr(h.hash0))
@ -927,13 +936,13 @@ next:
}
}
if (b.tophash[offi] != evacuatedX && b.tophash[offi] != evacuatedY) ||
!(t.reflexivekey || equalfn(k, k)) {
!(t.reflexivekey() || equalfn(k, k)) {
// This is the golden data, we can return it.
// OR
// key!=key, so the entry can't be deleted or updated, so we can just return it.
// That's lucky for us because when key!=key we can't look it up successfully.
it.key = k
if t.indirectvalue {
if t.indirectvalue() {
v = *((*unsafe.Pointer)(v))
}
it.value = v
@ -1157,7 +1166,7 @@ func evacuate(t *maptype, h *hmap, oldbucket uintptr) {
throw("bad map state")
}
k2 := k
if t.indirectkey {
if t.indirectkey() {
k2 = *((*unsafe.Pointer)(k2))
}
var useY uint8
@ -1165,7 +1174,7 @@ func evacuate(t *maptype, h *hmap, oldbucket uintptr) {
// Compute hash to make our evacuation decision (whether we need
// to send this key/value to bucket x or bucket y).
hash := t.key.hashfn(k2, uintptr(h.hash0))
if h.flags&iterator != 0 && !t.reflexivekey && !t.key.equalfn(k2, k2) {
if h.flags&iterator != 0 && !t.reflexivekey() && !t.key.equalfn(k2, k2) {
// If key != key (NaNs), then the hash could be (and probably
// will be) entirely different from the old hash. Moreover,
// it isn't reproducible. Reproducibility is required in the
@ -1200,12 +1209,12 @@ func evacuate(t *maptype, h *hmap, oldbucket uintptr) {
dst.v = add(dst.k, bucketCnt*uintptr(t.keysize))
}
dst.b.tophash[dst.i&(bucketCnt-1)] = top // mask dst.i as an optimization, to avoid a bounds check
if t.indirectkey {
if t.indirectkey() {
*(*unsafe.Pointer)(dst.k) = k2 // copy pointer
} else {
typedmemmove(t.key, dst.k, k) // copy value
}
if t.indirectvalue {
if t.indirectvalue() {
*(*unsafe.Pointer)(dst.v) = *(*unsafe.Pointer)(v)
} else {
typedmemmove(t.elem, dst.v, v)
@ -1271,12 +1280,12 @@ func reflect_makemap(t *maptype, cap int) *hmap {
if !ismapkey(t.key) {
throw("runtime.reflect_makemap: unsupported map key type")
}
if t.key.size > maxKeySize && (!t.indirectkey || t.keysize != uint8(sys.PtrSize)) ||
t.key.size <= maxKeySize && (t.indirectkey || t.keysize != uint8(t.key.size)) {
if t.key.size > maxKeySize && (!t.indirectkey() || t.keysize != uint8(sys.PtrSize)) ||
t.key.size <= maxKeySize && (t.indirectkey() || t.keysize != uint8(t.key.size)) {
throw("key size wrong")
}
if t.elem.size > maxValueSize && (!t.indirectvalue || t.valuesize != uint8(sys.PtrSize)) ||
t.elem.size <= maxValueSize && (t.indirectvalue || t.valuesize != uint8(t.elem.size)) {
if t.elem.size > maxValueSize && (!t.indirectvalue() || t.valuesize != uint8(sys.PtrSize)) ||
t.elem.size <= maxValueSize && (t.indirectvalue() || t.valuesize != uint8(t.elem.size)) {
throw("value size wrong")
}
if t.key.align > bucketCnt {

37
libgo/go/runtime/type.go
View File

@ -86,17 +86,32 @@ type interfacetype struct {
}
type maptype struct {
typ _type
key *_type
elem *_type
bucket *_type // internal type representing a hash bucket
keysize uint8 // size of key slot
indirectkey bool // store ptr to key instead of key itself
valuesize uint8 // size of value slot
indirectvalue bool // store ptr to value instead of value itself
bucketsize uint16 // size of bucket
reflexivekey bool // true if k==k for all keys
needkeyupdate bool // true if we need to update key on an overwrite
typ _type
key *_type
elem *_type
bucket *_type // internal type representing a hash bucket
keysize uint8 // size of key slot
valuesize uint8 // size of value slot
bucketsize uint16 // size of bucket
flags uint32
}
// Note: flag values must match those used in the TMAP case
// in ../cmd/compile/internal/gc/reflect.go:dtypesym.
func (mt *maptype) indirectkey() bool { // store ptr to key instead of key itself
return mt.flags&1 != 0
}
func (mt *maptype) indirectvalue() bool { // store ptr to value instead of value itself
return mt.flags&2 != 0
}
func (mt *maptype) reflexivekey() bool { // true if k==k for all keys
return mt.flags&4 != 0
}
func (mt *maptype) needkeyupdate() bool { // true if we need to update key on an overwrite
return mt.flags&8 != 0
}
func (mt *maptype) hashMightPanic() bool { // true if hash function might panic
return mt.flags&16 != 0
}
type arraytype struct {