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52 lines
1.4 KiB
Markdown
52 lines
1.4 KiB
Markdown
---
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title: Debugging Tools
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description: Overview of debugging tools supported in RIOT-OS
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---
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## Undefined Behavior Sanitizer (ubsan)
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RIOT contains Makefile convenience support for gcc/clang's undefined
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behaviour sanitizer.
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### Overview
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Both gcc and clang allow generation of code that does runtime checks for
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undefined behavior (UB).
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E.g., the following code might trigger UB for some parameters:
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```c
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void test(int foo) {
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return (foo << 24);
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}
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```
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In this case, the signed shift would be alright unless:
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- it would "push out" all bits to the left, with undefined runtime result. Here,
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that happens on architectures with 16-bit integers.
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- `foo` is negative, with implementation-specific runtime results.
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Using ubsan, these can be caught at runtime.
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There are three modes for ubsan that define what happens when the sanitizer
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observed undefined behaviour:
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1. `trap` -> cause a trap
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2. `msg_exit` -> print a message and exit
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3. `msg_recover` -> print a message and continue
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`trap` is available on all RIOT platforms, whereas `msg_exit` and `msg_recover`
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are currently only available on `native` when building with gcc, as they require runtime support in
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the form of `libubsan`.
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The default is `trap`, or `msg_exit` if available (currently, on native:gnu only).
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### How to Use
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1. build with `make all-ubsan`.
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2. build with `UBSAN_MODE=[trap|msg_exit|msg_recover] make all-ubsan` to
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override the ubsan mode.
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