Documentation ¶
Index ¶
- Constants
- func CommonSize(ptrSize int) int
- func StructFieldSize(ptrSize int) int
- func TFlagOff(ptrSize int) int
- func UncommonSize() uint64
- func UseInterfaceSwitchCache(goarch string) bool
- type ArrayType
- type ChanDir
- type ChanType
- type FuncFlag
- type FuncID
- type FuncType
- type Imethod
- type IntArgRegBitmap
- type InterfaceSwitch
- type InterfaceSwitchCache
- type InterfaceSwitchCacheEntry
- type InterfaceType
- type Kind
- type MapType
- type Method
- type Name
- func (n Name) Data(off int) *byte
- func (n Name) DataChecked(off int, whySafe string) *byte
- func (n Name) HasTag() bool
- func (n Name) IsBlank() bool
- func (n Name) IsEmbedded() bool
- func (n Name) IsExported() bool
- func (n Name) Name() string
- func (n Name) ReadVarint(off int) (int, int)
- func (n Name) Tag() string
- type NameOff
- type PtrType
- type RegArgs
- type SliceType
- type StructField
- type StructType
- type TFlag
- type TextOff
- type Type
- func (t *Type) Align() int
- func (t *Type) ArrayType() *ArrayType
- func (t *Type) ChanDir() ChanDir
- func (t *Type) Common() *Type
- func (t *Type) Elem() *Type
- func (t *Type) ExportedMethods() []Method
- func (t *Type) FieldAlign() int
- func (t *Type) FuncType() *FuncType
- func (t *Type) GcSlice(begin, end uintptr) []byte
- func (t *Type) HasName() bool
- func (t *Type) IfaceIndir() bool
- func (t *Type) InterfaceType() *InterfaceType
- func (t *Type) IsDirectIface() bool
- func (t *Type) Key() *Type
- func (t *Type) Kind() Kind
- func (t *Type) Len() int
- func (t *Type) MapType() *MapType
- func (t *Type) NumMethod() int
- func (t *Type) Pointers() bool
- func (t *Type) Size() uintptr
- func (t *Type) StructType() *StructType
- func (t *Type) Uncommon() *UncommonType
- type TypeAssert
- type TypeAssertCache
- type TypeAssertCacheEntry
- type TypeOff
- type UncommonType
Constants ¶
const ( // RAX, RBX, RCX, RDI, RSI, R8, R9, R10, R11. IntArgRegs = 9 // X0 -> X14. FloatArgRegs = 15 // We use SSE2 registers which support 64-bit float operations. EffectiveFloatRegSize = 8 )
const ( MapBucketCountBits = 3 // log2 of number of elements in a bucket. MapBucketCount = 1 << MapBucketCountBits MapMaxKeyBytes = 128 // Must fit in a uint8. MapMaxElemBytes = 128 // Must fit in a uint8. )
Map constants common to several packages runtime/runtime-gdb.py:MapTypePrinter contains its own copy
const ( // StackNosplitBase is the base maximum number of bytes that a chain of // NOSPLIT functions can use. // // This value must be multiplied by the stack guard multiplier, so do not // use it directly. See runtime/stack.go:stackNosplit and // cmd/internal/objabi/stack.go:StackNosplit. StackNosplitBase = 800 // After a stack split check the SP is allowed to be StackSmall bytes below // the stack guard. // // Functions that need frames <= StackSmall can perform the stack check // using a single comparison directly between the stack guard and the SP // because we ensure that StackSmall bytes of stack space are available // beyond the stack guard. StackSmall = 128 // Functions that need frames <= StackBig can assume that neither // SP-framesize nor stackGuard-StackSmall will underflow, and thus use a // more efficient check. In order to ensure this, StackBig must be <= the // size of the unmapped space at zero. StackBig = 4096 )
const ( PCDATA_UnsafePoint = 0 PCDATA_StackMapIndex = 1 PCDATA_InlTreeIndex = 2 PCDATA_ArgLiveIndex = 3 FUNCDATA_ArgsPointerMaps = 0 FUNCDATA_LocalsPointerMaps = 1 FUNCDATA_StackObjects = 2 FUNCDATA_InlTree = 3 FUNCDATA_OpenCodedDeferInfo = 4 FUNCDATA_ArgInfo = 5 FUNCDATA_ArgLiveInfo = 6 FUNCDATA_WrapInfo = 7 )
IDs for PCDATA and FUNCDATA tables in Go binaries.
These must agree with ../../../runtime/funcdata.h.
const ( UnsafePointSafe = -1 // Safe for async preemption UnsafePointUnsafe = -2 // Unsafe for async preemption // UnsafePointRestart1(2) apply on a sequence of instructions, within // which if an async preemption happens, we should back off the PC // to the start of the sequence when resuming. // We need two so we can distinguish the start/end of the sequence // in case that two sequences are next to each other. UnsafePointRestart1 = -3 UnsafePointRestart2 = -4 // Like UnsafePointRestart1, but back to function entry if async preempted. UnsafePointRestartAtEntry = -5 )
Special values for the PCDATA_UnsafePoint table.
const ( // TODO (khr, drchase) why aren't these in TFlag? Investigate, fix if possible. KindDirectIface = 1 << 5 KindGCProg = 1 << 6 // Type.gc points to GC program KindMask = (1 << 5) - 1 )
const ArgsSizeUnknown = -0x80000000
ArgsSizeUnknown is set in Func.argsize to mark all functions whose argument size is unknown (C vararg functions, and assembly code without an explicit specification). This value is generated by the compiler, assembler, or linker.
const ZeroValSize = 1024
ZeroValSize is the size in bytes of runtime.zeroVal.
Variables ¶
This section is empty.
Functions ¶
func CommonSize ¶ added in v0.7.2202
CommonSize returns sizeof(Type) for a compilation target with a given ptrSize
func StructFieldSize ¶ added in v0.7.2202
StructFieldSize returns sizeof(StructField) for a compilation target with a given ptrSize
func TFlagOff ¶ added in v0.7.2202
TFlagOff returns the offset of Type.TFlag for a compilation target with a given ptrSize
func UncommonSize ¶ added in v0.7.2202
func UncommonSize() uint64
UncommonSize returns sizeof(UncommonType). This currently does not depend on ptrSize. This exported function is in an internal package, so it may change to depend on ptrSize in the future.
func UseInterfaceSwitchCache ¶ added in v0.7.2202
Types ¶
type ArrayType ¶ added in v0.7.2202
type ArrayType struct { Type Elem *Type // array element type Slice *Type // slice type Len uintptr }
ArrayType represents a fixed array type.
type FuncFlag ¶ added in v0.7.2202
type FuncFlag uint8
A FuncFlag records bits about a function, passed to the runtime.
const ( // FuncFlagTopFrame indicates a function that appears at the top of its stack. // The traceback routine stop at such a function and consider that a // successful, complete traversal of the stack. // Examples of TopFrame functions include goexit, which appears // at the top of a user goroutine stack, and mstart, which appears // at the top of a system goroutine stack. FuncFlagTopFrame FuncFlag = 1 << iota // FuncFlagSPWrite indicates a function that writes an arbitrary value to SP // (any write other than adding or subtracting a constant amount). // The traceback routines cannot encode such changes into the // pcsp tables, so the function traceback cannot safely unwind past // SPWrite functions. Stopping at an SPWrite function is considered // to be an incomplete unwinding of the stack. In certain contexts // (in particular garbage collector stack scans) that is a fatal error. FuncFlagSPWrite // FuncFlagAsm indicates that a function was implemented in assembly. FuncFlagAsm )
type FuncID ¶ added in v0.7.2202
type FuncID uint8
A FuncID identifies particular functions that need to be treated specially by the runtime. Note that in some situations involving plugins, there may be multiple copies of a particular special runtime function.
const ( FuncIDNormal FuncID = iota // not a special function FuncID_abort FuncID_asmcgocall FuncID_asyncPreempt FuncID_cgocallback FuncID_corostart FuncID_debugCallV2 FuncID_gcBgMarkWorker FuncID_goexit FuncID_gogo FuncID_gopanic FuncID_handleAsyncEvent FuncID_mcall FuncID_morestack FuncID_mstart FuncID_panicwrap FuncID_rt0_go FuncID_runfinq FuncID_runtime_main FuncID_sigpanic FuncID_systemstack FuncID_systemstack_switch FuncIDWrapper // any autogenerated code (hash/eq algorithms, method wrappers, etc.) )
type FuncType ¶ added in v0.7.2202
type FuncType struct { Type InCount uint16 OutCount uint16 // top bit is set if last input parameter is ... }
funcType represents a function type.
A *Type for each in and out parameter is stored in an array that directly follows the funcType (and possibly its uncommonType). So a function type with one method, one input, and one output is:
struct { funcType uncommonType [2]*rtype // [0] is in, [1] is out }
func (*FuncType) IsVariadic ¶ added in v0.7.2202
type IntArgRegBitmap ¶
type IntArgRegBitmap [(IntArgRegs + 7) / 8]uint8
IntArgRegBitmap is a bitmap large enough to hold one bit per integer argument/return register.
func (*IntArgRegBitmap) Get ¶
func (b *IntArgRegBitmap) Get(i int) bool
Get returns whether the i'th bit of the bitmap is set.
nosplit because it's called in extremely sensitive contexts, like on the reflectcall return path.
func (*IntArgRegBitmap) Set ¶
func (b *IntArgRegBitmap) Set(i int)
Set sets the i'th bit of the bitmap to 1.
type InterfaceSwitch ¶ added in v0.7.2202
type InterfaceSwitch struct { Cache *InterfaceSwitchCache NCases int // Array of NCases elements. // Each case must be a non-empty interface type. Cases [1]*InterfaceType }
type InterfaceSwitchCache ¶ added in v0.7.2202
type InterfaceSwitchCache struct { Mask uintptr // mask for index. Must be a power of 2 minus 1 Entries [1]InterfaceSwitchCacheEntry // Mask+1 entries total }
type InterfaceSwitchCacheEntry ¶ added in v0.7.2202
type InterfaceType ¶ added in v0.7.2202
func (*InterfaceType) NumMethod ¶ added in v0.7.2202
func (t *InterfaceType) NumMethod() int
NumMethod returns the number of interface methods in the type's method set.
type Kind ¶ added in v0.7.2202
type Kind uint
A Kind represents the specific kind of type that a Type represents. The zero Kind is not a valid kind.
type MapType ¶ added in v0.7.2202
type MapType struct { Type Key *Type Elem *Type Bucket *Type // internal type representing a hash bucket // function for hashing keys (ptr to key, seed) -> hash Hasher func(unsafe.Pointer, uintptr) uintptr KeySize uint8 // size of key slot ValueSize uint8 // size of elem slot BucketSize uint16 // size of bucket Flags uint32 }
func (*MapType) HashMightPanic ¶ added in v0.7.2202
func (*MapType) IndirectElem ¶ added in v0.7.2202
func (*MapType) IndirectKey ¶ added in v0.7.2202
Note: flag values must match those used in the TMAP case in ../cmd/compile/internal/reflectdata/reflect.go:writeType.
func (*MapType) NeedKeyUpdate ¶ added in v0.7.2202
func (*MapType) ReflexiveKey ¶ added in v0.7.2202
type Method ¶ added in v0.7.2202
type Method struct { Name NameOff // name of method Mtyp TypeOff // method type (without receiver) Ifn TextOff // fn used in interface call (one-word receiver) Tfn TextOff // fn used for normal method call }
Method on non-interface type
type Name ¶ added in v0.7.2202
type Name struct {
Bytes *byte
}
func (Name) Data ¶ added in v0.7.2202
Data does pointer arithmetic on n's Bytes, and that arithmetic is asserted to be safe because the runtime made the call (other packages use DataChecked)
func (Name) DataChecked ¶ added in v0.7.2202
DataChecked does pointer arithmetic on n's Bytes, and that arithmetic is asserted to be safe for the reason in whySafe (which can appear in a backtrace, etc.)
func (Name) HasTag ¶ added in v0.7.2202
HasTag returns true iff there is tag data following this name
func (Name) IsEmbedded ¶ added in v0.7.2202
IsEmbedded returns true iff n is embedded (an anonymous field).
func (Name) IsExported ¶ added in v0.7.2202
IsExported returns "is n exported?"
func (Name) ReadVarint ¶ added in v0.7.2202
ReadVarint parses a varint as encoded by encoding/binary. It returns the number of encoded bytes and the encoded value.
type NameOff ¶ added in v0.7.2202
type NameOff int32
NameOff is the offset to a name from moduledata.types. See resolveNameOff in runtime.
type RegArgs ¶
type RegArgs struct { // Values in these slots should be precisely the bit-by-bit // representation of how they would appear in a register. // // This means that on big endian arches, integer values should // be in the top bits of the slot. Floats are usually just // directly represented, but some architectures treat narrow // width floating point values specially (e.g. they're promoted // first, or they need to be NaN-boxed). Ints [IntArgRegs]uintptr // untyped integer registers Floats [FloatArgRegs]uint64 // untyped float registers // Ptrs is a space that duplicates Ints but with pointer type, // used to make pointers passed or returned in registers // visible to the GC by making the type unsafe.Pointer. Ptrs [IntArgRegs]unsafe.Pointer // ReturnIsPtr is a bitmap that indicates which registers // contain or will contain pointers on the return path from // a reflectcall. The i'th bit indicates whether the i'th // register contains or will contain a valid Go pointer. ReturnIsPtr IntArgRegBitmap }
RegArgs is a struct that has space for each argument and return value register on the current architecture.
Assembly code knows the layout of the first two fields of RegArgs.
RegArgs also contains additional space to hold pointers when it may not be safe to keep them only in the integer register space otherwise.
func (*RegArgs) IntRegArgAddr ¶
IntRegArgAddr returns a pointer inside of r.Ints[reg] that is appropriately offset for an argument of size argSize.
argSize must be non-zero, fit in a register, and a power-of-two.
This method is a helper for dealing with the endianness of different CPU architectures, since sub-word-sized arguments in big endian architectures need to be "aligned" to the upper edge of the register to be interpreted by the CPU correctly.
type StructField ¶ added in v0.7.2202
type StructField struct { Name Name // name is always non-empty Typ *Type // type of field Offset uintptr // byte offset of field }
func (*StructField) Embedded ¶ added in v0.7.2202
func (f *StructField) Embedded() bool
type StructType ¶ added in v0.7.2202
type StructType struct { Type PkgPath Name Fields []StructField }
type TFlag ¶ added in v0.7.2202
type TFlag uint8
TFlag is used by a Type to signal what extra type information is available in the memory directly following the Type value.
const ( // TFlagUncommon means that there is a data with a type, UncommonType, // just beyond the shared-per-type common data. That is, the data // for struct types will store their UncommonType at one offset, the // data for interface types will store their UncommonType at a different // offset. UncommonType is always accessed via a pointer that is computed // using trust-us-we-are-the-implementors pointer arithmetic. // // For example, if t.Kind() == Struct and t.tflag&TFlagUncommon != 0, // then t has UncommonType data and it can be accessed as: // // type structTypeUncommon struct { // structType // u UncommonType // } // u := &(*structTypeUncommon)(unsafe.Pointer(t)).u TFlagUncommon TFlag = 1 << 0 // TFlagExtraStar means the name in the str field has an // extraneous '*' prefix. This is because for most types T in // a program, the type *T also exists and reusing the str data // saves binary size. TFlagExtraStar TFlag = 1 << 1 // TFlagNamed means the type has a name. TFlagNamed TFlag = 1 << 2 // TFlagRegularMemory means that equal and hash functions can treat // this type as a single region of t.size bytes. TFlagRegularMemory TFlag = 1 << 3 // TFlagUnrolledBitmap marks special types that are unrolled-bitmap // versions of types with GC programs. // These types need to be deallocated when the underlying object // is freed. TFlagUnrolledBitmap TFlag = 1 << 4 )
type TextOff ¶ added in v0.7.2202
type TextOff int32
TextOff is an offset from the top of a text section. See (rtype).textOff in runtime.
type Type ¶ added in v0.7.2202
type Type struct { Size_ uintptr PtrBytes uintptr // number of (prefix) bytes in the type that can contain pointers Hash uint32 // hash of type; avoids computation in hash tables TFlag TFlag // extra type information flags Align_ uint8 // alignment of variable with this type FieldAlign_ uint8 // alignment of struct field with this type Kind_ uint8 // enumeration for C // function for comparing objects of this type // (ptr to object A, ptr to object B) -> ==? Equal func(unsafe.Pointer, unsafe.Pointer) bool // GCData stores the GC type data for the garbage collector. // If the KindGCProg bit is set in kind, GCData is a GC program. // Otherwise it is a ptrmask bitmap. See mbitmap.go for details. GCData *byte Str NameOff // string form PtrToThis TypeOff // type for pointer to this type, may be zero }
Type is the runtime representation of a Go type.
Be careful about accessing this type at build time, as the version of this type in the compiler/linker may not have the same layout as the version in the target binary, due to pointer width differences and any experiments. Use cmd/compile/internal/rttype or the functions in compiletype.go to access this type instead. (TODO: this admonition applies to every type in this package. Put it in some shared location?)
func (*Type) ArrayType ¶ added in v0.7.2202
ArrayType returns t cast to a *ArrayType, or nil if its tag does not match.
func (*Type) ChanDir ¶ added in v0.7.2202
ChanDir returns the direction of t if t is a channel type, otherwise InvalidDir (0).
func (*Type) Elem ¶ added in v0.7.2202
Elem returns the element type for t if t is an array, channel, map, pointer, or slice, otherwise nil.
func (*Type) ExportedMethods ¶ added in v0.7.2202
func (*Type) FieldAlign ¶ added in v0.7.2202
func (*Type) FuncType ¶ added in v0.7.2202
FuncType returns t cast to a *FuncType, or nil if its tag does not match.
func (*Type) IfaceIndir ¶ added in v0.7.2202
IfaceIndir reports whether t is stored indirectly in an interface value.
func (*Type) InterfaceType ¶ added in v0.7.2202
func (t *Type) InterfaceType() *InterfaceType
InterfaceType returns t cast to a *InterfaceType, or nil if its tag does not match.
func (*Type) IsDirectIface ¶ added in v0.7.2202
isDirectIface reports whether t is stored directly in an interface value.
func (*Type) Len ¶ added in v0.7.2202
Len returns the length of t if t is an array type, otherwise 0
func (*Type) MapType ¶ added in v0.7.2202
MapType returns t cast to a *MapType, or nil if its tag does not match.
func (*Type) StructType ¶ added in v0.7.2202
func (t *Type) StructType() *StructType
StructType returns t cast to a *StructType, or nil if its tag does not match.
func (*Type) Uncommon ¶ added in v0.7.2202
func (t *Type) Uncommon() *UncommonType
Uncommon returns a pointer to T's "uncommon" data if there is any, otherwise nil
type TypeAssert ¶ added in v0.7.2202
type TypeAssert struct { Cache *TypeAssertCache Inter *InterfaceType CanFail bool }
type TypeAssertCache ¶ added in v0.7.2202
type TypeAssertCache struct { Mask uintptr Entries [1]TypeAssertCacheEntry }
type TypeAssertCacheEntry ¶ added in v0.7.2202
type TypeOff ¶ added in v0.7.2202
type TypeOff int32
TypeOff is the offset to a type from moduledata.types. See resolveTypeOff in runtime.
type UncommonType ¶ added in v0.7.2202
type UncommonType struct { PkgPath NameOff // import path; empty for built-in types like int, string Mcount uint16 // number of methods Xcount uint16 // number of exported methods Moff uint32 // offset from this uncommontype to [mcount]Method // contains filtered or unexported fields }
UncommonType is present only for defined types or types with methods (if T is a defined type, the uncommonTypes for T and *T have methods). Using a pointer to this struct reduces the overall size required to describe a non-defined type with no methods.
func (*UncommonType) ExportedMethods ¶ added in v0.7.2202
func (t *UncommonType) ExportedMethods() []Method
func (*UncommonType) Methods ¶ added in v0.7.2202
func (t *UncommonType) Methods() []Method