1 堆与栈
For declared variables in Go, they need to be allocated as objects in memory where either in the heap or on the stack
Stack frames:
- local storage space belonging to a function
- where stored objects are managed by the belonging frame's lifecycle
- allocation is cheap (only requires two CPU instructions: to push onto the stack for allocation, and to release from the stack)
- allocating objects on the stack is faster than in the heap (no locking / no GC/ less overhead)
Heap:
- global storage space
- where stored objects are managed by the GC
- allocation is expensive
2 逃逸分析
1. A mechanism to automatically decide wheter a variable should be allocated in the heap of not in compile time (是一种静态分析). It tries to keep variables on the stack as much as possible (Go prefers allocation on the stack). If a variable would be allocated in the heap, the variable is escaped.
2. 图：Go编译过程
3. Generally, a variable escapes if:
- its address has been caputred by the address-of (&) operator
- and? at least one of the related variables has already escaped
Reference