Chapter 7 Run-Time Environments

A compiler must accurately implement the abstractions embodied in the source-language definition. These abstractions typically include the concepts we discussed in Section 1.6 such as names, scopes, bindings, data types, operators,procedures, parameters, and flow-of-control constructs. The compiler must cooperate with the operating system and other systems software to support these abstractions on the target machine.

NOTE: 上面这段话中的**abstractions**是有特殊含义的，参见文章Abstraction。

Compiler需要使用machine language来实现programming language中的各种abstraction。

To do so, the compiler creates and manages a run-time environment in which it assumes its target programs are being executed. This environment deals with a variety of issues such as the layout and allocation of storage locations for the objects named in the source program, the mechanisms used by the target program to access variables, the linkages between procedures, the mechanisms for passing parameters, and the interfaces to the operating system, input/output devices, and other programs.

NOTE: 显然，**run-time environment**是一个概念模型（是一个简化的模型，没有考虑multi-thread等），关于对这个概念模型的实现，参见工程Linux-OS的Process mode: run time environment。

本段描述的这些内容是由Application binary interface所约定。

The two themes in this chapter are the allocation of storage locations and access to variables and data. We shall discuss memory management in some detail, including stack allocation, heap management, and garbage collection. In the next chapter, we present techniques for generating target code for many common language constructs.

NOTE: 本章的内容是比较重要的，因为process在运行过程中的主要活动都是发生在stack和heap。