Stack usage and stack usage control files

Introduction

The stack is described in "IAR C/C++ Development Guide", chapter "Storage of auto variables and parameters". This technical note describes how to get stack usage statistics from an application, and also shows the syntax of stack usage control files (.suc).

Example

Download and open the example project from the link: Example project for IAR Embedded Workbench for ARM 7.20.1.zip.

Description

The simple example project contains a 'main' and a 'test_func' function. To enable stack usage analysis, the following project option is enabled: Project > Options > Linker > Advanced > Enable stack usage analysis

The linker map file now contains stack usage information in the section called "STACK USAGE". For example:

Maximum call chain 20 bytes

"__iar_program_start" 0
"__cmain" 0
"main" 16
"test_func" 4

The example project also contains two interrupt handlers: 'SysTick_Handler' and 'UsageFault_Handler'. It also contains an OS task: 'test_task'. These functions are not (directly) called by anyone, so in the Stack Usage Control file (.suc), the following must be specified:

call graph root [task] : test_task;
call graph root [interrupt] : SysTick_Handler, UsageFault_Handler;

call graph root [task] : test_task;
call graph root [interrupt] : SysTick_Handler, UsageFault_Handler;

With the above, stack usage analysis now knows that these (not called) functions are "call graph roots". (Note that instead of using a control file, it is possible to use
#pragma call_graph_root directly in the code).

More information

See "IAR C/C++ Development Guide", chapter "Stack usage analysis".
For Stack Usage Control file syntax, see chapter "The stack usage control file".

To get run-time stack usage information while debugging in C-SPY, enable: Tools > Options > Stack > 'Enable graphical stack display and stack usage tracking'. In C-SPY, open the View > Stack window.

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