goexit bool
}
-// stack traces
+// A stkframe holds information about a single physical stack frame.
type stkframe struct {
- fn funcInfo // function being run
- pc uintptr // program counter within fn
- continpc uintptr // program counter where execution can continue, or 0 if not
- lr uintptr // program counter at caller aka link register
- sp uintptr // stack pointer at pc
- fp uintptr // stack pointer at caller aka frame pointer
- varp uintptr // top of local variables
- argp uintptr // pointer to function arguments
- arglen uintptr // number of bytes at argp
- argmap *bitvector // force use of this argmap
+ // fn is the function being run in this frame. If there is
+ // inlining, this is the outermost function.
+ fn funcInfo
+
+ // pc is the program counter within fn.
+ //
+ // The meaning of this is subtle:
+ //
+ // - Typically, this frame performed a regular function call
+ // and this is the return PC (just after the CALL
+ // instruction). In this case, pc-1 reflects the CALL
+ // instruction itself and is the correct source of symbolic
+ // information.
+ //
+ // - If this frame "called" sigpanic, then pc is the
+ // instruction that panicked, and pc is the correct address
+ // to use for symbolic information.
+ //
+ // - If this is the innermost frame, then PC is where
+ // execution will continue, but it may not be the
+ // instruction following a CALL. This may be from
+ // cooperative preemption, in which case this is the
+ // instruction after the call to morestack. Or this may be
+ // from a signal or an un-started goroutine, in which case
+ // PC could be any instruction, including the first
+ // instruction in a function. Conventionally, we use pc-1
+ // for symbolic information, unless pc == fn.entry(), in
+ // which case we use pc.
+ pc uintptr
+
+ // continpc is the PC where execution will continue in fn, or
+ // 0 if execution will not continue in this frame.
+ //
+ // This is usually the same as pc, unless this frame "called"
+ // sigpanic, in which case it's either the address of
+ // deferreturn or 0 if this frame will never execute again.
+ //
+ // This is the PC to use to look up GC liveness for this frame.
+ continpc uintptr
+
+ lr uintptr // program counter at caller aka link register
+ sp uintptr // stack pointer at pc
+ fp uintptr // stack pointer at caller aka frame pointer
+ varp uintptr // top of local variables
+ argp uintptr // pointer to function arguments
+ arglen uintptr // number of bytes at argp
+ argmap *bitvector // force use of this argmap
}
// ancestorInfo records details of where a goroutine was started.