Noescape case "go:norace": return Norace case "go:nosplit": return Nosplit case "go:noinline": return Noinline case "go:systemstack": should be removed return (((x << 5) >> 2) << 2) } runtime/atomic_pointer.go //go:nosplit func atomicstorep(ptr unsafe.Pointer, new unsafe.Pointer) { writebarrierptr_prewrite((*uintptr)(ptr) *SysProcAttr, pipe int) (pid int, err Errno) { Should you use /go:norace in your own code? //go:nosplit Function preamble ".fn t=1 size=120 args=0x0 locals=0x80 0x0000 00000 (main.go:5) TEXT ".fn(SB)

in add_amd64.s. #include "textflag.h" // func Add(x, y uint64) uint64 TEXT · Add(SB), NOSPLIT, $0-24 MOVQ x+0(FP), AX MOVQ y+8(FP), CX ADDQ CX, AX MOVQ AX, ret+16(FP) RET Implementation in add_amd64.s. #include "textflag.h" // func Add(x, y uint64) uint64 TEXT · Add(SB), NOSPLIT, $0-24 MOVQ x+0(FP), AX MOVQ y+8(FP), CX ADDQ CX, AX MOVQ AX, ret+16(FP) RET Declaration Implementation in add_amd64.s. #include "textflag.h" // func Add(x, y uint64) uint64 TEXT · Add(SB), NOSPLIT, $0-24 MOVQ x+0(FP), AX < Read x from stack frame MOVQ y+8(FP), CX < Read y ADDQ CX, AX MOVQ

newstack morestack_noctxt ## ↓ morestack ↓ newstack ## ☀️ ☀️ ☁️ TEXT runtime·morestack(SB),NOSPLIT,$0-0 get_tls(CX) MOVQ g(CX), SI // 将 caller g 保存在 SI 寄存器中 // 根据 caller 信息，设置 g.sched 的 pc、g、sp scan g stack -> resumeG M sighandler returned gsignal ☀️ ☁️ ☁️ TEXT ·asyncPreempt(SB),NOSPLIT|NOFRAME,$0-0 PC G local var a // 保存所有通用/非通用寄存器到 goroutine 栈上 CALL ·asyncPreempt2(SB) local gsignal G local var a local var b local var c ctx.PC ctx.SP ●●●● TEXT · asyncPreempt(SB), NOSPLIT|NOFRAME, $0-0 PC // 保存所有通用/非通用寄存器到 goroutine 栈上 CALL ·asyncPreempt2(SB) // 从栈上恢复所有通用/非通用寄存器