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Jake Bailey 18033ebc36 compiler, runtime, reflect: generate type-specific hash/equal (#5359)
* compiler, runtime, reflect: generate type-specific hash/equal for composite map keys

For map keys that are not trivially binary-comparable, the compiler now
generates type-specific hash and equal functions as LLVM IR instead of
going through the interface+reflection path. This covers comparable
types: strings, floats, complex numbers, interfaces, channels, and
composites containing any mix of these.

Previously, maps with composite keys containing strings or floats
converted the key to interface{}, hashed via reflection, and compared
through interface equality. Now the compiler walks struct fields and
array elements directly, dispatching to the right runtime helper for
each field type and storing keys at their actual type.

Struct keys are always handled field-by-field so padding bytes do not
affect equality or hashing. Blank fields are ignored, matching Go
equality. Generated hash/equal function names use canonical underlying
type structure so structurally identical key types can share generated
functions. Padding zeroing before map operations is no longer needed
because structs no longer use the binary key path.

Also fix reflect map iteration for interface-keyed maps: MapIter.Key
returns an interface Value for map[interface{}] keys instead of
unpacking to the concrete key kind.

* compiler: generate loops for array map key hash/equal

Previously, array key hash and equal functions were unrolled at compile
time, generating one block of IR per element. For large arrays like
[1000]int inside a struct with non-binary fields, this caused code
explosion.

Now, binary-element arrays dispatch directly to hash32/memequal for the
whole array. Non-binary-element arrays generate an LLVM IR loop. The
equal loop short-circuits on the first mismatch.

Small arrays are still unrolled instead of looping, keeping the simple
cases compact.

* reflect: fix at-runtime map issues from review, and more found locally

Maps created through reflect.MakeMap need hash/equal behavior that
matches compiler-created maps. Add hashmapMakeReflect for composite key
types, using runtime closures that reconstruct interface{} values from
raw key bytes and delegate to the interface hash and equality paths.

Interface-keyed maps are already stored as interface values, so use the
existing interface hash/equal helpers directly for those. This keeps
reflect insert, lookup, delete, and compiled lookup paths consistent.

Also fix addressable small values used as interface map keys or
interface map values. loadSmallValue puts small indirect values back in
the pointer-sized interface data field the same way valueInterfaceUnsafe
does.

* compiler, interp, reflect: fix pointer map literals; remove interface fallback

Package-level map literals with pointer keys (both *T and
unsafe.Pointer) crash the compiler: the interp pass panics when trying
to hash pointer data as raw bytes, because pointer values in the interp
memory model are symbolic identities that do not fit in a byte.

Fix this by setting a recoverable error flag instead of panicking. The
interp detects the error after each instruction and defers the map
insert to runtime init code, where real addresses are available for
hashing. This matches how the interp already handles other operations
it cannot evaluate at compile time.

With this fix, unsafe.Pointer can also be classified as a binary map
key, which was the last type requiring the interface-based fallback.
Since all comparable types now use either the binary or the
compiler-generated hash/equal path, remove the interface fallback from
the compiler and reflect packages.

* compiler, transform: always pass hash/equal function pointers to hashmapMakeGeneric

The compiler now always resolves the hash and equal functions at compile
time and passes them directly to hashmapMakeGeneric, instead of passing
an algorithm enum to hashmapMake and resolving at runtime. For string
keys, the runtime hashmapStringPtrHash/hashmapStringEqual functions are
referenced directly. For binary keys, hash32/memequal are referenced.

The old hashmapMake with alg enum is retained for reflect, which still
needs runtime resolution when creating maps dynamically.

The OptimizeMaps transform pass is updated to handle both hashmapMake
and hashmapMakeGeneric, and to recognize hashmapGenericSet in addition
to hashmapBinarySet and hashmapStringSet. The now-unused
hashmapCanGenerateHashEqual helper is removed.

* runtime: store large map keys and values indirectly

When a map key or value exceeds 128 bytes, the bucket now stores a
pointer to separately allocated memory instead of the data inline. This
matches Go's MapMaxKeyBytes/MapMaxElemBytes threshold and prevents
bucket sizes from exploding for large key/value types.

For example, map[[256]byte]int previously used 2128 bytes per bucket
(16 header + 256*8 keys + 8*8 values); now it uses 144 bytes per bucket
(16 header + 8*8 pointers + 8*8 values).

The indirection is fully encapsulated in the runtime via helper
functions. Store the computed key and value slot sizes on the hashmap so
all runtime and reflect paths use the same bucket layout, including
non-indirect keys and values.

Add big-key golden coverage and benchmarks. Make the benchmark vary
enough key bytes to exercise hashing.
2026-05-18 13:31:27 +02:00

534 lines
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Plaintext

matching types
true
false
false
false
false
false
values of interfaces
reflect type: bool name=bool
bool: true
reflect type: bool name=bool
bool: false
reflect type: int name=int
int: 2000
reflect type: int name=int
int: -2000
reflect type: uint name=uint
uint: 2000
reflect type: int8 name=int8
int: -3
reflect type: int8 name=int8
int: 3
reflect type: uint8 name=uint8
uint: 200
reflect type: int16 name=int16
int: -300
reflect type: int16 name=int16
int: 300
reflect type: uint16 name=uint16
uint: 50000
reflect type: int32 name=int32
int: 7340032
reflect type: int32 name=int32
int: -7340032
reflect type: uint32 name=uint32
uint: 7340032
reflect type: int64 name=int64
int: 9895604649984
reflect type: int64 name=int64
int: -9895604649984
reflect type: uint64 name=uint64
uint: 9895604649984
reflect type: uintptr name=uintptr
uint: 12345
reflect type: float32 name=float32
float: +3.140000e+000
reflect type: float64 name=float64
float: +3.140000e+000
reflect type: complex64 name=complex64
complex: (+1.200000e+000+3.000000e-001i)
reflect type: complex128 name=complex128
complex: (+1.300000e+000+4.000000e-001i)
reflect type: int name=myint
int: 32
reflect type: string name=string
string: foo 3
reflect type: uint8 name=uint8
uint: 102
reflect type: uint8 name=uint8
uint: 111
reflect type: uint8 name=uint8
uint: 111
reflect type: unsafe.Pointer name=Pointer
pointer: true
reflect type: chan
chan: int
nil: true
reflect type: chan name=mychan
chan: int
nil: true
reflect type: ptr
pointer: true int
nil: false
reflect type: int settable=true addrable=true name=int
int: 0
reflect type: ptr
pointer: true interface
nil: false
reflect type: interface settable=true addrable=true name=error
interface
nil: true
NumMethod: 1
reflect type: ptr
pointer: true int
nil: false
reflect type: int settable=true addrable=true name=int
int: 42
reflect type: ptr name=myptr
pointer: true int
nil: false
reflect type: int settable=true addrable=true name=int
int: 0
reflect type: slice comparable=false
slice: uint8 3 3
pointer: true
nil: false
indexing: 0
reflect type: uint8 settable=true addrable=true name=uint8
uint: 1
indexing: 1
reflect type: uint8 settable=true addrable=true name=uint8
uint: 2
indexing: 2
reflect type: uint8 settable=true addrable=true name=uint8
uint: 3
reflect type: slice comparable=false
slice: uint8 2 5
pointer: true
nil: false
indexing: 0
reflect type: uint8 settable=true addrable=true name=uint8
uint: 0
indexing: 1
reflect type: uint8 settable=true addrable=true name=uint8
uint: 0
reflect type: slice comparable=false
slice: int32 2 2
pointer: true
nil: false
indexing: 0
reflect type: int32 settable=true addrable=true name=int32
int: 3
indexing: 1
reflect type: int32 settable=true addrable=true name=int32
int: 5
reflect type: slice comparable=false
slice: string 2 2
pointer: true
nil: false
indexing: 0
reflect type: string settable=true addrable=true name=string
string: xyz 3
reflect type: uint8 name=uint8
uint: 120
reflect type: uint8 name=uint8
uint: 121
reflect type: uint8 name=uint8
uint: 122
indexing: 1
reflect type: string settable=true addrable=true name=string
string: Z 1
reflect type: uint8 name=uint8
uint: 90
reflect type: slice comparable=false
slice: uint8 0 0
pointer: false
nil: true
reflect type: slice comparable=false
slice: uint8 0 0
pointer: true
nil: false
reflect type: slice comparable=false
slice: float32 2 2
pointer: true
nil: false
indexing: 0
reflect type: float32 settable=true addrable=true name=float32
float: +1.000000e+000
indexing: 1
reflect type: float32 settable=true addrable=true name=float32
float: +1.320000e+000
reflect type: slice comparable=false
slice: float64 2 2
pointer: true
nil: false
indexing: 0
reflect type: float64 settable=true addrable=true name=float64
float: +1.000000e+000
indexing: 1
reflect type: float64 settable=true addrable=true name=float64
float: +1.640000e+000
reflect type: slice comparable=false
slice: complex64 2 2
pointer: true
nil: false
indexing: 0
reflect type: complex64 settable=true addrable=true name=complex64
complex: (+1.000000e+000+0.000000e+000i)
indexing: 1
reflect type: complex64 settable=true addrable=true name=complex64
complex: (+1.640000e+000+3.000000e-001i)
reflect type: slice comparable=false
slice: complex128 2 2
pointer: true
nil: false
indexing: 0
reflect type: complex128 settable=true addrable=true name=complex128
complex: (+1.000000e+000+0.000000e+000i)
indexing: 1
reflect type: complex128 settable=true addrable=true name=complex128
complex: (+1.128000e+000+4.000000e-001i)
reflect type: slice comparable=false name=myslice
slice: uint8 3 3
pointer: true
nil: false
indexing: 0
reflect type: uint8 settable=true addrable=true name=uint8
uint: 5
indexing: 1
reflect type: uint8 settable=true addrable=true name=uint8
uint: 3
indexing: 2
reflect type: uint8 settable=true addrable=true name=uint8
uint: 11
reflect type: array
array: 3 int64 24
reflect type: int64 name=int64
int: 5
reflect type: int64 name=int64
int: 8
reflect type: int64 name=int64
int: 2
reflect type: array
array: 2 uint8 2
reflect type: uint8 name=uint8
uint: 3
reflect type: uint8 name=uint8
uint: 5
reflect type: func comparable=false
func
nil: true
reflect type: func comparable=false
func
nil: false
reflect type: map comparable=false
map
nil: true
reflect type: map comparable=false
map
nil: false
reflect type: struct
struct: 0
reflect type: struct
struct: 1
field: 0 error
pkg: main
tag: ""
embedded: true
exported: false
reflect type: interface caninterface=false name=error
interface
nil: true
NumMethod: 1
reflect type: struct
struct: 3
field: 0 a
pkg: main
tag: ""
embedded: false
exported: false
reflect type: uint8 caninterface=false name=uint8
uint: 42
field: 1 b
pkg: main
tag: ""
embedded: false
exported: false
reflect type: int16 caninterface=false name=int16
int: 321
field: 2 c
pkg: main
tag: ""
embedded: false
exported: false
reflect type: int8 caninterface=false name=int8
int: 123
reflect type: struct comparable=false name=mystruct
struct: 5
field: 0 n
pkg: main
tag: "foo:\"bar\""
embedded: false
exported: false
reflect type: int caninterface=false name=int
int: 5
field: 1 some
pkg: main
tag: "some\x00tag"
embedded: false
exported: false
reflect type: struct caninterface=false name=point
struct: 2
field: 0 X
pkg:
tag: ""
embedded: false
exported: true
reflect type: int16 caninterface=false name=int16
int: -5
field: 1 Y
pkg:
tag: ""
embedded: false
exported: true
reflect type: int16 caninterface=false name=int16
int: 3
field: 2 zero
pkg: main
tag: ""
embedded: false
exported: false
reflect type: struct caninterface=false
struct: 0
field: 3 buf
pkg: main
tag: ""
embedded: false
exported: false
reflect type: slice caninterface=false comparable=false
slice: uint8 2 2
pointer: true
nil: false
indexing: 0
reflect type: uint8 addrable=true caninterface=false name=uint8
uint: 71
indexing: 1
reflect type: uint8 addrable=true caninterface=false name=uint8
uint: 111
field: 4 Buf
pkg:
tag: ""
embedded: false
exported: true
reflect type: slice comparable=false
slice: uint8 1 1
pointer: true
nil: false
indexing: 0
reflect type: uint8 settable=true addrable=true name=uint8
uint: 88
reflect type: ptr
pointer: true struct
nil: false
reflect type: struct settable=true addrable=true name=linkedList
struct: 2
field: 0 next
pkg: main
tag: "description:\"chain\""
embedded: false
exported: false
reflect type: ptr addrable=true caninterface=false
pointer: false struct
nil: true
field: 1 foo
pkg: main
tag: ""
embedded: false
exported: false
reflect type: int addrable=true caninterface=false name=int
int: 42
reflect type: struct
struct: 2
field: 0 A
pkg:
tag: ""
embedded: false
exported: true
reflect type: uintptr name=uintptr
uint: 2
field: 1 B
pkg:
tag: ""
embedded: false
exported: true
reflect type: uintptr name=uintptr
uint: 3
reflect type: slice comparable=false
slice: interface 3 3
pointer: true
nil: false
indexing: 0
reflect type: interface settable=true addrable=true
interface
nil: false
NumMethod: 0
reflect type: int name=int
int: 3
indexing: 1
reflect type: interface settable=true addrable=true
interface
nil: false
NumMethod: 0
reflect type: string name=string
string: str 3
reflect type: uint8 name=uint8
uint: 115
reflect type: uint8 name=uint8
uint: 116
reflect type: uint8 name=uint8
uint: 114
indexing: 2
reflect type: interface settable=true addrable=true
interface
nil: false
NumMethod: 0
reflect type: complex128 name=complex128
complex: (-4.000000e+000+2.500000e+000i)
reflect type: ptr
pointer: true int8
nil: false
reflect type: int8 settable=true addrable=true name=int8
int: 5
reflect type: ptr
pointer: true int16
nil: false
reflect type: int16 settable=true addrable=true name=int16
int: -800
reflect type: ptr
pointer: true int32
nil: false
reflect type: int32 settable=true addrable=true name=int32
int: 100000000
reflect type: ptr
pointer: true int64
nil: false
reflect type: int64 settable=true addrable=true name=int64
int: -1000000000000
reflect type: ptr
pointer: true complex128
nil: false
reflect type: complex128 settable=true addrable=true name=complex128
complex: (-8.000000e+000-2.000000e+006i)
sizes:
int8 1 8
int16 2 16
int32 4 32
int64 8 64
uint8 1 8
uint16 2 16
uint32 4 32
uint64 8 64
float32 4 32
float64 8 64
complex64 8 64
complex128 16 128
offset for int64 matches: true
offset for complex128 matches: true
type assertion succeeded for unreferenced type
interface implements
concrete implements:
myReader → Reader: true
*myReader → Reader: true
myWriter → Writer: false
*myWriter → Writer: true
myReadWriter → Reader: true
myReadWriter → Writer: false
myReadWriter → ReadWriter: false
*myReadWriter → Reader: true
*myReadWriter → Writer: true
*myReadWriter → ReadWriter: true
myReader → Closer: false
*myReadWriter → Closer: false
errorValue → error: true
errorValue → Stringer: false
myErrorStringer → error: true
myErrorStringer → Stringer: true
myReader → interface{}: true
int → interface{}: true
interface implements interface:
ReadWriter → Reader: true
ReadWriter → Writer: true
Reader → ReadWriter: false
Writer → ReadWriter: false
ReadCloser → Reader: true
ReadCloser → Closer: true
ReadCloser → Writer: false
Reader → ReadCloser: false
Reader → Reader: true
ReadWriter → ReadWriter: true
error → Stringer: false
Stringer → error: false
Reader → interface{}: true
ReadWriter → interface{}: true
assignable to:
int → int: true
string → string: true
int → string: false
int → int64: false
myReader → Reader: true
*myWriter → Writer: true
myWriter → Writer: false
*myReadWriter → ReadWriter: true
ReadWriter → Reader: true
Reader → ReadWriter: false
int → interface{}: true
Reader → interface{}: true
unexported method interface:
*notAnExpr → exprLike: true
notAnExpr → exprLike: true
*notAnExpr → exprLike (AssignableTo): true
channel direction:
chan int → <-chan int: true
<-chan int → chan int: false
named types:
*int → IntPtr: true
IntPtr → *int: true
IntPtr → IntPtr1: false
Ch → <-chan interface{}: true
value set interface:
Set[0] to BarNode: 10
Set[1] still FooNode: 2
reflect.MakeMap composite key:
len: 2
key1: 100
key2: 200
after delete, len: 1
key2 after delete: 200
reflect.MakeMap interface key:
len: 2
42: 100
hello: 200
compiled 42: 100
compiled hello: 200
addressable 99: 300
reflect.MakeMap padded key:
padded lookup: 100
alignment / offset:
struct{[0]func(); byte}: true
struct tags
blue gopher
v.Interface() method
kind: interface
int 5
reflect map interface key ok