Stack-based memory allocation
Encyclopedia
Stack
s in computing architectures are regions of memory where data is added or removed in a last-in-first-out manner.
In most modern computer systems, each thread
has a reserved region of memory referred to as its stack. When a function executes, it may add some of its state data to the top of the stack; when the function exits it is responsible for removing that data from the stack. At a minimum, a thread's stack is used to store the location of function calls in order to allow return statements to return to the correct location, but programmers may further choose to explicitly use the stack. If a region of memory lies on the thread's stack, that memory is said to have been allocated on the stack.
Because the data is added and removed in a last-in-first-out manner, stack allocation is very simple and typically faster than heap-based memory allocation (also known as dynamic memory allocation). Another feature is that memory on the stack is automatically, and very efficiently, reclaimed when the function exits, which can be convenient for the programmer if the data is no longer required. If however, the data needs to be kept in some form, then it must be copied from the stack before the function exits. Therefore, stack based allocation is suitable for temporary data or data which is no longer required after the creating function exits.
A disadvantage of stack-based memory allocation is that a thread's stack size can be as small as a few dozen kilobytes. Allocating more memory on the stack than is available can result in a crash
due to stack overflow
.
Some processors families, such as the x86, have special instructions for manipulating the stack of the currently executing thread. Other processor families, including PowerPC
and MIPS
, do not have explicit stack support, but instead rely on convention and delegate stack management to the operating system's Application Binary Interface (ABI)
.
Stack (data structure)
In computer science, a stack is a last in, first out abstract data type and linear data structure. A stack can have any abstract data type as an element, but is characterized by only three fundamental operations: push, pop and stack top. The push operation adds a new item to the top of the stack,...
s in computing architectures are regions of memory where data is added or removed in a last-in-first-out manner.
In most modern computer systems, each thread
Thread (computer science)
In computer science, a thread of execution is the smallest unit of processing that can be scheduled by an operating system. The implementation of threads and processes differs from one operating system to another, but in most cases, a thread is contained inside a process...
has a reserved region of memory referred to as its stack. When a function executes, it may add some of its state data to the top of the stack; when the function exits it is responsible for removing that data from the stack. At a minimum, a thread's stack is used to store the location of function calls in order to allow return statements to return to the correct location, but programmers may further choose to explicitly use the stack. If a region of memory lies on the thread's stack, that memory is said to have been allocated on the stack.
Because the data is added and removed in a last-in-first-out manner, stack allocation is very simple and typically faster than heap-based memory allocation (also known as dynamic memory allocation). Another feature is that memory on the stack is automatically, and very efficiently, reclaimed when the function exits, which can be convenient for the programmer if the data is no longer required. If however, the data needs to be kept in some form, then it must be copied from the stack before the function exits. Therefore, stack based allocation is suitable for temporary data or data which is no longer required after the creating function exits.
A disadvantage of stack-based memory allocation is that a thread's stack size can be as small as a few dozen kilobytes. Allocating more memory on the stack than is available can result in a crash
Crash (computing)
A crash in computing is a condition where a computer or a program, either an application or part of the operating system, ceases to function properly, often exiting after encountering errors. Often the offending program may appear to freeze or hang until a crash reporting service documents...
due to stack overflow
Stack overflow
In software, a stack overflow occurs when too much memory is used on the call stack. The call stack contains a limited amount of memory, often determined at the start of the program. The size of the call stack depends on many factors, including the programming language, machine architecture,...
.
Some processors families, such as the x86, have special instructions for manipulating the stack of the currently executing thread. Other processor families, including PowerPC
PowerPC
PowerPC is a RISC architecture created by the 1991 Apple–IBM–Motorola alliance, known as AIM...
and MIPS
MIPS architecture
MIPS is a reduced instruction set computer instruction set architecture developed by MIPS Technologies . The early MIPS architectures were 32-bit, and later versions were 64-bit...
, do not have explicit stack support, but instead rely on convention and delegate stack management to the operating system's Application Binary Interface (ABI)
Application binary interface
In computer software, an application binary interface describes the low-level interface between an application program and the operating system or another application.- Description :...
.
See also
- Automatic variable
- Call stackCall stackIn computer science, a call stack is a stack data structure that stores information about the active subroutines of a computer program. This kind of stack is also known as an execution stack, control stack, run-time stack, or machine stack, and is often shortened to just "the stack"...
- Dynamic memory allocation
- Stack buffer overflowStack buffer overflowIn software, a stack buffer overflow occurs when a program writes to a memory address on the program's call stack outside of the intended data structure; usually a fixed length buffer....
- Stack machineStack machineA stack machine may be* A real or emulated computer that evaluates each sub-expression of a program statement via a pushdown data stack and uses a reverse Polish notation instruction set....