reflect: add write barriers
Use typedmemmove, typedslicecopy, and adjust reflect.call
to execute the necessary write barriers.
Found with GODEBUG=wbshadow=2 mode.
Eventually that will run automatically, but right now
it still detects other missing write barriers.
Change-Id: Iec5b5b0c1be5589295e28e5228e37f1a92e07742
Reviewed-on: https://go-review.googlesource.com/2312
Reviewed-by: Keith Randall <khr@golang.org>
diff --git a/src/reflect/value.go b/src/reflect/value.go
index c34679d..652dee2 100644
--- a/src/reflect/value.go
+++ b/src/reflect/value.go
@@ -107,7 +107,7 @@
// TODO: pass safe boolean from valueInterface so
// we don't need to copy if safe==true?
c := unsafe_New(t)
- memmove(c, ptr, t.size)
+ typedmemmove(t, c, ptr)
ptr = c
}
e.word = ptr
@@ -412,7 +412,7 @@
addr := unsafe.Pointer(uintptr(args) + off)
v = v.assignTo("reflect.Value.Call", targ, addr)
if v.flag&flagIndir != 0 {
- memmove(addr, v.ptr, n)
+ typedmemmove(targ, addr, v.ptr)
} else {
*(*unsafe.Pointer)(addr) = v.ptr
}
@@ -420,7 +420,7 @@
}
// Call.
- call(fn, args, uint32(frametype.size), uint32(retOffset))
+ call(frametype, fn, args, uint32(frametype.size), uint32(retOffset))
// For testing; see TestCallMethodJump.
if callGC {
@@ -473,7 +473,7 @@
// and we cannot let f keep a reference to the stack frame
// after this function returns, not even a read-only reference.
v.ptr = unsafe_New(typ)
- memmove(v.ptr, addr, typ.size)
+ typedmemmove(typ, v.ptr, addr)
v.flag |= flagIndir
} else {
v.ptr = *(*unsafe.Pointer)(addr)
@@ -509,7 +509,7 @@
off += -off & uintptr(typ.align-1)
addr := unsafe.Pointer(uintptr(ptr) + off)
if v.flag&flagIndir != 0 {
- memmove(addr, v.ptr, typ.size)
+ typedmemmove(typ, addr, v.ptr)
} else {
*(*unsafe.Pointer)(addr) = v.ptr
}
@@ -603,10 +603,10 @@
// Copy in receiver and rest of args.
storeRcvr(rcvr, args)
- memmove(unsafe.Pointer(uintptr(args)+ptrSize), frame, argSize-ptrSize)
+ typedmemmovepartial(frametype, unsafe.Pointer(uintptr(args)+ptrSize), frame, ptrSize, argSize-ptrSize)
// Call.
- call(fn, args, uint32(frametype.size), uint32(retOffset))
+ call(frametype, fn, args, uint32(frametype.size), uint32(retOffset))
// Copy return values. On amd64p32, the beginning of return values
// is 64-bit aligned, so the caller's frame layout (which doesn't have
@@ -617,8 +617,11 @@
if runtime.GOARCH == "amd64p32" {
callerRetOffset = align(argSize-ptrSize, 8)
}
- memmove(unsafe.Pointer(uintptr(frame)+callerRetOffset),
- unsafe.Pointer(uintptr(args)+retOffset), frametype.size-retOffset)
+ typedmemmovepartial(frametype,
+ unsafe.Pointer(uintptr(frame)+callerRetOffset),
+ unsafe.Pointer(uintptr(args)+retOffset),
+ retOffset,
+ frametype.size-retOffset)
}
// funcName returns the name of f, for use in error messages.
@@ -1017,7 +1020,7 @@
// Copy result so future changes to the map
// won't change the underlying value.
c := unsafe_New(typ)
- memmove(c, e, typ.size)
+ typedmemmove(typ, c, e)
return Value{typ, c, fl | flagIndir}
} else {
return Value{typ, *(*unsafe.Pointer)(e), fl}
@@ -1055,7 +1058,7 @@
// Copy result so future changes to the map
// won't change the underlying value.
c := unsafe_New(keyType)
- memmove(c, key, keyType.size)
+ typedmemmove(keyType, c, key)
a[i] = Value{keyType, c, fl | flagIndir}
} else {
a[i] = Value{keyType, *(*unsafe.Pointer)(key), fl}
@@ -1301,7 +1304,7 @@
}
x = x.assignTo("reflect.Set", v.typ, target)
if x.flag&flagIndir != 0 {
- memmove(v.ptr, x.ptr, v.typ.size)
+ typedmemmove(v.typ, v.ptr, x.ptr)
} else {
*(*unsafe.Pointer)(v.ptr) = x.ptr
}
@@ -1815,27 +1818,23 @@
se := src.typ.Elem()
typesMustMatch("reflect.Copy", de, se)
- n := dst.Len()
- if sn := src.Len(); n > sn {
- n = sn
+ var ds, ss sliceHeader
+ if dk == Array {
+ ds.Data = dst.ptr
+ ds.Len = dst.Len()
+ ds.Cap = ds.Len
+ } else {
+ ds = *(*sliceHeader)(dst.ptr)
+ }
+ if sk == Array {
+ ss.Data = src.ptr
+ ss.Len = src.Len()
+ ss.Cap = ss.Len
+ } else {
+ ss = *(*sliceHeader)(src.ptr)
}
- // Copy via memmove.
- var da, sa unsafe.Pointer
- if dk == Array {
- da = dst.ptr
- } else {
- da = (*sliceHeader)(dst.ptr).Data
- }
- if src.flag&flagIndir == 0 {
- sa = unsafe.Pointer(&src.ptr)
- } else if sk == Array {
- sa = src.ptr
- } else {
- sa = (*sliceHeader)(src.ptr).Data
- }
- memmove(da, sa, uintptr(n)*de.Size())
- return n
+ return typedslicecopy(de.common(), ds, ss)
}
// A runtimeSelect is a single case passed to rselect.
@@ -2376,7 +2375,7 @@
if f&flagAddr != 0 {
// indirect, mutable word - make a copy
c := unsafe_New(t)
- memmove(c, ptr, t.size)
+ typedmemmove(t, c, ptr)
ptr = c
f &^= flagAddr
}
@@ -2425,12 +2424,29 @@
func mapiterkey(it unsafe.Pointer) (key unsafe.Pointer)
func mapiternext(it unsafe.Pointer)
func maplen(m unsafe.Pointer) int
-func call(fn, arg unsafe.Pointer, n uint32, retoffset uint32)
+
+// call calls fn with a copy of the n argument bytes pointed at by arg.
+// After fn returns, reflectcall copies n-retoffset result bytes
+// back into arg+retoffset before returning. If copying result bytes back,
+// the caller must pass the argument frame type as argtype, so that
+// call can execute appropriate write barriers during the copy.
+func call(argtype *rtype, fn, arg unsafe.Pointer, n uint32, retoffset uint32)
func ifaceE2I(t *rtype, src interface{}, dst unsafe.Pointer)
+// typedmemmove copies a value of type t to dst from src.
//go:noescape
-func memmove(adst, asrc unsafe.Pointer, n uintptr)
+func typedmemmove(t *rtype, dst, src unsafe.Pointer)
+
+// typedmemmovepartial is like typedmemmove but assumes that
+// dst and src point off bytes into the value and only copies size bytes.
+//go:noescape
+func typedmemmovepartial(t *rtype, dst, src unsafe.Pointer, off, size uintptr)
+
+// typedslicecopy copies a slice of elemType values from src to dst,
+// returning the number of elements copied.
+//go:noescape
+func typedslicecopy(elemType *rtype, dst, src sliceHeader) int
// Dummy annotation marking that the value x escapes,
// for use in cases where the reflect code is so clever that
diff --git a/src/runtime/asm_386.s b/src/runtime/asm_386.s
index 14e4360..4de7c43 100644
--- a/src/runtime/asm_386.s
+++ b/src/runtime/asm_386.s
@@ -329,7 +329,7 @@
JMP runtime·morestack(SB)
// reflectcall: call a function with the given argument list
-// func call(f *FuncVal, arg *byte, argsize, retoffset uint32).
+// func call(argtype *_type, f *FuncVal, arg *byte, argsize, retoffset uint32).
// we don't have variable-sized frames, so we use a small number
// of constant-sized-frame functions to encode a few bits of size in the pc.
// Caution: ugly multiline assembly macros in your future!
@@ -344,8 +344,8 @@
TEXT reflect·call(SB), NOSPLIT, $0-0
JMP ·reflectcall(SB)
-TEXT ·reflectcall(SB), NOSPLIT, $0-16
- MOVL argsize+8(FP), CX
+TEXT ·reflectcall(SB), NOSPLIT, $0-20
+ MOVL argsize+12(FP), CX
DISPATCH(runtime·call16, 16)
DISPATCH(runtime·call32, 32)
DISPATCH(runtime·call64, 64)
@@ -377,27 +377,37 @@
JMP AX
#define CALLFN(NAME,MAXSIZE) \
-TEXT NAME(SB), WRAPPER, $MAXSIZE-16; \
+TEXT NAME(SB), WRAPPER, $MAXSIZE-20; \
NO_LOCAL_POINTERS; \
/* copy arguments to stack */ \
- MOVL argptr+4(FP), SI; \
- MOVL argsize+8(FP), CX; \
+ MOVL argptr+8(FP), SI; \
+ MOVL argsize+12(FP), CX; \
MOVL SP, DI; \
REP;MOVSB; \
/* call function */ \
- MOVL f+0(FP), DX; \
+ MOVL f+4(FP), DX; \
MOVL (DX), AX; \
PCDATA $PCDATA_StackMapIndex, $0; \
CALL AX; \
/* copy return values back */ \
- MOVL argptr+4(FP), DI; \
- MOVL argsize+8(FP), CX; \
- MOVL retoffset+12(FP), BX; \
+ MOVL argptr+8(FP), DI; \
+ MOVL argsize+12(FP), CX; \
+ MOVL retoffset+16(FP), BX; \
MOVL SP, SI; \
ADDL BX, DI; \
ADDL BX, SI; \
SUBL BX, CX; \
REP;MOVSB; \
+ /* execute write barrier updates */ \
+ MOVL argtype+0(FP), DX; \
+ MOVL argptr+8(FP), DI; \
+ MOVL argsize+12(FP), CX; \
+ MOVL retoffset+16(FP), BX; \
+ MOVL DX, 0(SP); \
+ MOVL DI, 4(SP); \
+ MOVL CX, 8(SP); \
+ MOVL BX, 12(SP); \
+ CALL runtime·callwritebarrier(SB); \
RET
CALLFN(·call16, 16)
diff --git a/src/runtime/asm_amd64.s b/src/runtime/asm_amd64.s
index 5a94e11..3e8ccca 100644
--- a/src/runtime/asm_amd64.s
+++ b/src/runtime/asm_amd64.s
@@ -318,7 +318,7 @@
JMP runtime·morestack(SB)
// reflectcall: call a function with the given argument list
-// func call(f *FuncVal, arg *byte, argsize, retoffset uint32).
+// func call(argtype *_type, f *FuncVal, arg *byte, argsize, retoffset uint32).
// we don't have variable-sized frames, so we use a small number
// of constant-sized-frame functions to encode a few bits of size in the pc.
// Caution: ugly multiline assembly macros in your future!
@@ -333,9 +333,10 @@
TEXT reflect·call(SB), NOSPLIT, $0-0
JMP ·reflectcall(SB)
-TEXT ·reflectcall(SB), NOSPLIT, $0-24
- MOVLQZX argsize+16(FP), CX
- DISPATCH(runtime·call16, 16)
+TEXT ·reflectcall(SB), NOSPLIT, $0-32
+ MOVLQZX argsize+24(FP), CX
+ // NOTE(rsc): No call16, because CALLFN needs four words
+ // of argument space to invoke callwritebarrier.
DISPATCH(runtime·call32, 32)
DISPATCH(runtime·call64, 64)
DISPATCH(runtime·call128, 128)
@@ -366,29 +367,38 @@
JMP AX
#define CALLFN(NAME,MAXSIZE) \
-TEXT NAME(SB), WRAPPER, $MAXSIZE-24; \
+TEXT NAME(SB), WRAPPER, $MAXSIZE-32; \
NO_LOCAL_POINTERS; \
/* copy arguments to stack */ \
- MOVQ argptr+8(FP), SI; \
- MOVLQZX argsize+16(FP), CX; \
+ MOVQ argptr+16(FP), SI; \
+ MOVLQZX argsize+24(FP), CX; \
MOVQ SP, DI; \
REP;MOVSB; \
/* call function */ \
- MOVQ f+0(FP), DX; \
+ MOVQ f+8(FP), DX; \
PCDATA $PCDATA_StackMapIndex, $0; \
CALL (DX); \
/* copy return values back */ \
- MOVQ argptr+8(FP), DI; \
- MOVLQZX argsize+16(FP), CX; \
- MOVLQZX retoffset+20(FP), BX; \
+ MOVQ argptr+16(FP), DI; \
+ MOVLQZX argsize+24(FP), CX; \
+ MOVLQZX retoffset+28(FP), BX; \
MOVQ SP, SI; \
ADDQ BX, DI; \
ADDQ BX, SI; \
SUBQ BX, CX; \
REP;MOVSB; \
+ /* execute write barrier updates */ \
+ MOVQ argtype+0(FP), DX; \
+ MOVQ argptr+16(FP), DI; \
+ MOVLQZX argsize+24(FP), CX; \
+ MOVLQZX retoffset+28(FP), BX; \
+ MOVQ DX, 0(SP); \
+ MOVQ DI, 8(SP); \
+ MOVQ CX, 16(SP); \
+ MOVQ BX, 24(SP); \
+ CALL runtime·callwritebarrier(SB); \
RET
-CALLFN(·call16, 16)
CALLFN(·call32, 32)
CALLFN(·call64, 64)
CALLFN(·call128, 128)
diff --git a/src/runtime/asm_amd64p32.s b/src/runtime/asm_amd64p32.s
index 20fb5df..f3752e7 100644
--- a/src/runtime/asm_amd64p32.s
+++ b/src/runtime/asm_amd64p32.s
@@ -290,7 +290,7 @@
JMP runtime·morestack(SB)
// reflectcall: call a function with the given argument list
-// func call(f *FuncVal, arg *byte, argsize, retoffset uint32).
+// func call(argtype *_type, f *FuncVal, arg *byte, argsize, retoffset uint32).
// we don't have variable-sized frames, so we use a small number
// of constant-sized-frame functions to encode a few bits of size in the pc.
// Caution: ugly multiline assembly macros in your future!
@@ -305,8 +305,8 @@
TEXT reflect·call(SB), NOSPLIT, $0-0
JMP ·reflectcall(SB)
-TEXT ·reflectcall(SB), NOSPLIT, $0-16
- MOVLQZX argsize+8(FP), CX
+TEXT ·reflectcall(SB), NOSPLIT, $0-20
+ MOVLQZX argsize+12(FP), CX
DISPATCH(runtime·call16, 16)
DISPATCH(runtime·call32, 32)
DISPATCH(runtime·call64, 64)
@@ -338,26 +338,36 @@
JMP AX
#define CALLFN(NAME,MAXSIZE) \
-TEXT NAME(SB), WRAPPER, $MAXSIZE-16; \
+TEXT NAME(SB), WRAPPER, $MAXSIZE-20; \
NO_LOCAL_POINTERS; \
/* copy arguments to stack */ \
- MOVL argptr+4(FP), SI; \
- MOVL argsize+8(FP), CX; \
+ MOVL argptr+8(FP), SI; \
+ MOVL argsize+12(FP), CX; \
MOVL SP, DI; \
REP;MOVSB; \
/* call function */ \
- MOVL f+0(FP), DX; \
+ MOVL f+4(FP), DX; \
MOVL (DX), AX; \
CALL AX; \
/* copy return values back */ \
- MOVL argptr+4(FP), DI; \
- MOVL argsize+8(FP), CX; \
- MOVL retoffset+12(FP), BX; \
+ MOVL argptr+8(FP), DI; \
+ MOVL argsize+12(FP), CX; \
+ MOVL retoffset+16(FP), BX; \
MOVL SP, SI; \
ADDL BX, DI; \
ADDL BX, SI; \
SUBL BX, CX; \
REP;MOVSB; \
+ /* execute write barrier updates */ \
+ MOVL argtype+0(FP), DX; \
+ MOVL argptr+8(FP), DI; \
+ MOVL argsize+12(FP), CX; \
+ MOVL retoffset+16(FP), BX; \
+ MOVL DX, 0(SP); \
+ MOVL DI, 4(SP); \
+ MOVL CX, 8(SP); \
+ MOVL BX, 12(SP); \
+ CALL runtime·callwritebarrier(SB); \
RET
CALLFN(·call16, 16)
diff --git a/src/runtime/asm_arm.s b/src/runtime/asm_arm.s
index fdcc0e6..3253942 100644
--- a/src/runtime/asm_arm.s
+++ b/src/runtime/asm_arm.s
@@ -322,7 +322,7 @@
B runtime·morestack(SB)
// reflectcall: call a function with the given argument list
-// func call(f *FuncVal, arg *byte, argsize, retoffset uint32).
+// func call(argtype *_type, f *FuncVal, arg *byte, argsize, retoffset uint32).
// we don't have variable-sized frames, so we use a small number
// of constant-sized-frame functions to encode a few bits of size in the pc.
// Caution: ugly multiline assembly macros in your future!
@@ -336,8 +336,8 @@
TEXT reflect·call(SB), NOSPLIT, $0-0
B ·reflectcall(SB)
-TEXT ·reflectcall(SB),NOSPLIT,$-4-16
- MOVW argsize+8(FP), R0
+TEXT ·reflectcall(SB),NOSPLIT,$-4-20
+ MOVW argsize+12(FP), R0
DISPATCH(runtime·call16, 16)
DISPATCH(runtime·call32, 32)
DISPATCH(runtime·call64, 64)
@@ -369,11 +369,11 @@
B (R1)
#define CALLFN(NAME,MAXSIZE) \
-TEXT NAME(SB), WRAPPER, $MAXSIZE-16; \
+TEXT NAME(SB), WRAPPER, $MAXSIZE-20; \
NO_LOCAL_POINTERS; \
/* copy arguments to stack */ \
- MOVW argptr+4(FP), R0; \
- MOVW argsize+8(FP), R2; \
+ MOVW argptr+8(FP), R0; \
+ MOVW argsize+12(FP), R2; \
ADD $4, SP, R1; \
CMP $0, R2; \
B.EQ 5(PC); \
@@ -382,24 +382,37 @@
SUB $1, R2, R2; \
B -5(PC); \
/* call function */ \
- MOVW f+0(FP), R7; \
+ MOVW f+4(FP), R7; \
MOVW (R7), R0; \
PCDATA $PCDATA_StackMapIndex, $0; \
BL (R0); \
/* copy return values back */ \
- MOVW argptr+4(FP), R0; \
- MOVW argsize+8(FP), R2; \
- MOVW retoffset+12(FP), R3; \
+ MOVW argptr+8(FP), R0; \
+ MOVW argsize+12(FP), R2; \
+ MOVW retoffset+16(FP), R3; \
ADD $4, SP, R1; \
ADD R3, R1; \
ADD R3, R0; \
SUB R3, R2; \
+loop:
CMP $0, R2; \
- RET.EQ ; \
+ B.EQ end; \
MOVBU.P 1(R1), R5; \
MOVBU.P R5, 1(R0); \
SUB $1, R2, R2; \
- B -5(PC) \
+ B loop; \
+end: \
+ /* execute write barrier updates */ \
+ MOVW argtype+0(FP), R1; \
+ MOVW argptr+8(FP), R0; \
+ MOVW argsize+12(FP), R2; \
+ MOVW retoffset+16(FP), R3; \
+ MOVW R1, 4(R13); \
+ MOVW R0, 8(R13); \
+ MOVW R2, 12(R13); \
+ MOVW R3, 16(R13); \
+ BL runtime·callwritebarrier(SB); \
+ RET
CALLFN(·call16, 16)
CALLFN(·call32, 32)
diff --git a/src/runtime/asm_ppc64x.s b/src/runtime/asm_ppc64x.s
index 1360c6e..8ec051d 100644
--- a/src/runtime/asm_ppc64x.s
+++ b/src/runtime/asm_ppc64x.s
@@ -271,7 +271,7 @@
BR runtime·morestack(SB)
// reflectcall: call a function with the given argument list
-// func call(f *FuncVal, arg *byte, argsize, retoffset uint32).
+// func call(argtype *_type, f *FuncVal, arg *byte, argsize, retoffset uint32).
// we don't have variable-sized frames, so we use a small number
// of constant-sized-frame functions to encode a few bits of size in the pc.
// Caution: ugly multiline assembly macros in your future!
@@ -288,9 +288,10 @@
TEXT reflect·call(SB), NOSPLIT, $0-0
BR ·reflectcall(SB)
-TEXT ·reflectcall(SB), NOSPLIT, $-8-24
- MOVWZ n+16(FP), R3
- DISPATCH(runtime·call16, 16)
+TEXT ·reflectcall(SB), NOSPLIT, $-8-32
+ MOVWZ argsize+24(FP), R3
+ // NOTE(rsc): No call16, because CALLFN needs four words
+ // of argument space to invoke callwritebarrier.
DISPATCH(runtime·call32, 32)
DISPATCH(runtime·call64, 64)
DISPATCH(runtime·call128, 128)
@@ -325,8 +326,8 @@
TEXT NAME(SB), WRAPPER, $MAXSIZE-24; \
NO_LOCAL_POINTERS; \
/* copy arguments to stack */ \
- MOVD arg+8(FP), R3; \
- MOVWZ n+16(FP), R4; \
+ MOVD arg+16(FP), R3; \
+ MOVWZ argsize+24(FP), R4; \
MOVD R1, R5; \
ADD $(8-1), R5; \
SUB $1, R3; \
@@ -337,15 +338,15 @@
MOVBZU R6, 1(R5); \
BR -4(PC); \
/* call function */ \
- MOVD f+0(FP), R11; \
+ MOVD f+8(FP), R11; \
MOVD (R11), R31; \
MOVD R31, CTR; \
PCDATA $PCDATA_StackMapIndex, $0; \
BL (CTR); \
/* copy return values back */ \
- MOVD arg+8(FP), R3; \
- MOVWZ n+16(FP), R4; \
- MOVWZ retoffset+20(FP), R6; \
+ MOVD arg+16(FP), R3; \
+ MOVWZ n+24(FP), R4; \
+ MOVWZ retoffset+28(FP), R6; \
MOVD R1, R5; \
ADD R6, R5; \
ADD R6, R3; \
@@ -353,11 +354,23 @@
ADD $(8-1), R5; \
SUB $1, R3; \
ADD R5, R4; \
+loop: \
CMP R5, R4; \
- BEQ 4(PC); \
+ BEQ end; \
MOVBZU 1(R5), R6; \
MOVBZU R6, 1(R3); \
- BR -4(PC); \
+ BR loop; \
+end: \
+ /* execute write barrier updates */ \
+ MOVD argtype+0(FP), R7; \
+ MOVD arg+16(FP), R3; \
+ MOVWZ n+24(FP), R4; \
+ MOVWZ retoffset+28(FP), R6; \
+ MOVD R7, 8(R1); \
+ MOVD R3, 16(R1); \
+ MOVD R4, 24(R1); \
+ MOVD R6, 32(R1); \
+ BL runtime·callwritebarrier(SB); \
RETURN
CALLFN(·call16, 16)
diff --git a/src/runtime/cgocall.go b/src/runtime/cgocall.go
index 52b48c46..dbeea20 100644
--- a/src/runtime/cgocall.go
+++ b/src/runtime/cgocall.go
@@ -232,7 +232,12 @@
}
// Invoke callback.
- reflectcall(unsafe.Pointer(cb.fn), unsafe.Pointer(cb.arg), uint32(cb.argsize), 0)
+ // NOTE(rsc): passing nil for argtype means that the copying of the
+ // results back into cb.arg happens without any corresponding write barriers.
+ // For cgo, cb.arg points into a C stack frame and therefore doesn't
+ // hold any pointers that the GC can find anyway - the write barrier
+ // would be a no-op.
+ reflectcall(nil, unsafe.Pointer(cb.fn), unsafe.Pointer(cb.arg), uint32(cb.argsize), 0)
if raceenabled {
racereleasemerge(unsafe.Pointer(&racecgosync))
diff --git a/src/runtime/malloc.go b/src/runtime/malloc.go
index 58e7702..22c0dfe 100644
--- a/src/runtime/malloc.go
+++ b/src/runtime/malloc.go
@@ -942,7 +942,7 @@
default:
throw("bad kind in runfinq")
}
- reflectcall(unsafe.Pointer(f.fn), frame, uint32(framesz), uint32(framesz))
+ reflectcall(nil, unsafe.Pointer(f.fn), frame, uint32(framesz), uint32(framesz))
// drop finalizer queue references to finalized object
f.fn = nil
diff --git a/src/runtime/mgc0.go b/src/runtime/mgc0.go
index 2833aa7..b9718cb 100644
--- a/src/runtime/mgc0.go
+++ b/src/runtime/mgc0.go
@@ -104,6 +104,7 @@
_PoisonStack = 0x6868686868686868 & (1<<(8*ptrSize) - 1)
)
+//go:nosplit
func needwb() bool {
return gcphase == _GCmark || gcphase == _GCmarktermination || mheap_.shadow_enabled
}
@@ -232,7 +233,7 @@
// Apply changes to shadow.
// Since *dst has been overwritten already, we cannot check
// whether there were any missed updates, but writebarrierptr_nostore
- // is only rarely used (right now there is just one call, in newstack).
+ // is only rarely used.
if mheap_.shadow_enabled {
systemstack(func() {
addr := uintptr(unsafe.Pointer(dst))
@@ -287,6 +288,12 @@
// all the combinations of ptr+scalar up to four words.
// The implementations are written to wbfat.go.
+//go:linkname reflect_typedmemmove reflect.typedmemmove
+func reflect_typedmemmove(typ *_type, dst, src unsafe.Pointer) {
+ typedmemmove(typ, dst, src)
+}
+
+// typedmemmove copies a value of type t to dst from src.
//go:nosplit
func typedmemmove(typ *_type, dst, src unsafe.Pointer) {
if !needwb() || (typ.kind&kindNoPointers) != 0 {
@@ -322,6 +329,79 @@
})
}
+// typedmemmovepartial is like typedmemmove but assumes that
+// dst and src point off bytes into the value and only copies size bytes.
+//go:linkname reflect_typedmemmovepartial reflect.typedmemmovepartial
+func reflect_typedmemmovepartial(typ *_type, dst, src unsafe.Pointer, off, size uintptr) {
+ if !needwb() || (typ.kind&kindNoPointers) != 0 || size < ptrSize {
+ memmove(dst, src, size)
+ return
+ }
+
+ if off&(ptrSize-1) != 0 {
+ frag := -off & (ptrSize - 1)
+ // frag < size, because size >= ptrSize, checked above.
+ memmove(dst, src, frag)
+ size -= frag
+ dst = add(noescape(dst), frag)
+ src = add(noescape(src), frag)
+ off += frag
+ }
+
+ mask := loadPtrMask(typ)
+ nptr := (off + size) / ptrSize
+ for i := uintptr(off / ptrSize); i < nptr; i++ {
+ bits := mask[i/2] >> ((i & 1) << 2)
+ if (bits>>2)&_BitsMask == _BitsPointer {
+ writebarrierptr((*uintptr)(dst), *(*uintptr)(src))
+ } else {
+ *(*uintptr)(dst) = *(*uintptr)(src)
+ }
+ // TODO(rsc): The noescape calls should be unnecessary.
+ dst = add(noescape(dst), ptrSize)
+ src = add(noescape(src), ptrSize)
+ }
+ size &= ptrSize - 1
+ if size > 0 {
+ memmove(dst, src, size)
+ }
+}
+
+// callwritebarrier is invoked at the end of reflectcall, to execute
+// write barrier operations to record the fact that a call's return
+// values have just been copied to frame, starting at retoffset
+// and continuing to framesize. The entire frame (not just the return
+// values) is described by typ. Because the copy has already
+// happened, we call writebarrierptr_nostore, and we must be careful
+// not to be preempted before the write barriers have been run.
+//go:nosplit
+func callwritebarrier(typ *_type, frame unsafe.Pointer, framesize, retoffset uintptr) {
+ if !needwb() || typ == nil || (typ.kind&kindNoPointers) != 0 || framesize-retoffset < ptrSize {
+ return
+ }
+
+ systemstack(func() {
+ mask := loadPtrMask(typ)
+ // retoffset is known to be pointer-aligned (at least).
+ // TODO(rsc): The noescape call should be unnecessary.
+ dst := add(noescape(frame), retoffset)
+ nptr := framesize / ptrSize
+ for i := uintptr(retoffset / ptrSize); i < nptr; i++ {
+ bits := mask[i/2] >> ((i & 1) << 2)
+ if (bits>>2)&_BitsMask == _BitsPointer {
+ writebarrierptr_nostore((*uintptr)(dst), *(*uintptr)(dst))
+ }
+ // TODO(rsc): The noescape call should be unnecessary.
+ dst = add(noescape(dst), ptrSize)
+ }
+ })
+}
+
+//go:linkname reflect_typedslicecopy reflect.typedslicecopy
+func reflect_typedslicecopy(elemType *_type, dst, src slice) int {
+ return typedslicecopy(elemType, dst, src)
+}
+
//go:nosplit
func typedslicecopy(typ *_type, dst, src slice) int {
n := dst.len
diff --git a/src/runtime/panic.go b/src/runtime/panic.go
index 393c769..09278af 100644
--- a/src/runtime/panic.go
+++ b/src/runtime/panic.go
@@ -301,7 +301,7 @@
continue
}
d.started = true
- reflectcall(unsafe.Pointer(d.fn), deferArgs(d), uint32(d.siz), uint32(d.siz))
+ reflectcall(nil, unsafe.Pointer(d.fn), deferArgs(d), uint32(d.siz), uint32(d.siz))
if gp._defer != d {
throw("bad defer entry in Goexit")
}
@@ -401,7 +401,7 @@
d._panic = (*_panic)(noescape((unsafe.Pointer)(&p)))
p.argp = unsafe.Pointer(getargp(0))
- reflectcall(unsafe.Pointer(d.fn), deferArgs(d), uint32(d.siz), uint32(d.siz))
+ reflectcall(nil, unsafe.Pointer(d.fn), deferArgs(d), uint32(d.siz), uint32(d.siz))
p.argp = nil
// reflectcall did not panic. Remove d.
diff --git a/src/runtime/stubs.go b/src/runtime/stubs.go
index 67f78bd..1114a09 100644
--- a/src/runtime/stubs.go
+++ b/src/runtime/stubs.go
@@ -110,7 +110,17 @@
func setg(gg *g)
func breakpoint()
-func reflectcall(fn, arg unsafe.Pointer, n uint32, retoffset uint32)
+// reflectcall calls fn with a copy of the n argument bytes pointed at by arg.
+// After fn returns, reflectcall copies n-retoffset result bytes
+// back into arg+retoffset before returning. If copying result bytes back,
+// the caller should pass the argument frame type as argtype, so that
+// call can execute appropriate write barriers during the copy.
+// Package reflect passes a frame type. In package runtime, there is only
+// one call that copies results back, in cgocallbackg1, and it does NOT pass a
+// frame type, meaning there are no write barriers invoked. See that call
+// site for justification.
+func reflectcall(argtype *_type, fn, arg unsafe.Pointer, argsize uint32, retoffset uint32)
+
func procyield(cycles uint32)
func cgocallback_gofunc(fv *funcval, frame unsafe.Pointer, framesize uintptr)
func goexit()
