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Add Natvis definitions and tests for SmallVec type with and without t…
…he `union` crate feature enabled. Unify Natvis definitions into a single Natvis file.
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| Original file line number | Diff line number | Diff line change |
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| ## Debugger Visualizers | ||
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| Many languages and debuggers enable developers to control how a type is | ||
| displayed in a debugger. These are called "debugger visualizations" or "debugger | ||
| views". | ||
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| The Windows debuggers (WinDbg\CDB) support defining custom debugger visualizations using | ||
| the `Natvis` framework. To use Natvis, developers write XML documents using the natvis | ||
| schema that describe how debugger types should be displayed with the `.natvis` extension. | ||
| (See: https://docs.microsoft.com/en-us/visualstudio/debugger/create-custom-views-of-native-objects?view=vs-2019) | ||
| The Natvis files provide patterns which match type names a description of how to display | ||
| those types. | ||
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| The Natvis schema can be found either online (See: https://code.visualstudio.com/docs/cpp/natvis#_schema) | ||
| or locally at `<VS Installation Folder>\Xml\Schemas\1033\natvis.xsd`. | ||
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| The GNU debugger (GDB) supports defining custom debugger views using Pretty Printers. | ||
| Pretty printers are written as python scripts that describe how a type should be displayed | ||
| when loaded up in GDB/LLDB. (See: https://sourceware.org/gdb/onlinedocs/gdb/Pretty-Printing.html#Pretty-Printing) | ||
| The pretty printers provide patterns, which match type names, and for matching | ||
| types, descibe how to display those types. (For writing a pretty printer, see: https://sourceware.org/gdb/onlinedocs/gdb/Writing-a-Pretty_002dPrinter.html#Writing-a-Pretty_002dPrinter). | ||
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| ### Embedding Visualizers | ||
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| Through the use of the currently unstable `#[debugger_visualizer]` attribute, the `smallvec` | ||
| crate can embed debugger visualizers into the crate metadata. | ||
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| Currently the two types of visualizers supported are Natvis and Pretty printers. | ||
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| For Natvis files, when linking an executable with a crate that includes Natvis files, | ||
| the MSVC linker will embed the contents of all Natvis files into the generated `PDB`. | ||
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| For pretty printers, the compiler will encode the contents of the pretty printer | ||
| in the `.debug_gdb_scripts` section of the `ELF` generated. | ||
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| ### Testing Visualizers | ||
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| The `smallvec` crate supports testing debugger visualizers defined for this crate. The entry point for | ||
| these tests are `tests/debugger_visualizer.rs`. These tests are defined using the `debugger_test` and | ||
| `debugger_test_parser` crates. The `debugger_test` crate is a proc macro crate which defines a | ||
| single proc macro attribute, `#[debugger_test]`. For more detailed information about this crate, | ||
| see https://crates.io/crates/debugger_test. The CI pipeline for the `smallvec` crate has been updated | ||
| to run the debugger visualizer tests to ensure debugger visualizers do not become broken/stale. | ||
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| The `#[debugger_test]` proc macro attribute may only be used on test functions and will run the | ||
| function under the debugger specified by the `debugger` meta item. | ||
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| This proc macro attribute has 3 required values: | ||
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| 1. The first required meta item, `debugger`, takes a string value which specifies the debugger to launch. | ||
| 2. The second required meta item, `commands`, takes a string of new line (`\n`) separated list of debugger | ||
| commands to run. | ||
| 3. The third required meta item, `expected_statements`, takes a string of new line (`\n`) separated list of | ||
| statements that must exist in the debugger output. Pattern matching through regular expressions is also | ||
| supported by using the `pattern:` prefix for each expected statement. | ||
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| #### Example: | ||
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| ```rust | ||
| #[debugger_test( | ||
| debugger = "cdb", | ||
| commands = "command1\ncommand2\ncommand3", | ||
| expected_statements = "statement1\nstatement2\nstatement3")] | ||
| fn test() { | ||
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| } | ||
| ``` | ||
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| Using a multiline string is also supported, with a single debugger command/expected statement per line: | ||
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| ```rust | ||
| #[debugger_test( | ||
| debugger = "cdb", | ||
| commands = " | ||
| command1 | ||
| command2 | ||
| command3", | ||
| expected_statements = " | ||
| statement1 | ||
| pattern:statement[0-9]+ | ||
| statement3")] | ||
| fn test() { | ||
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| } | ||
| ``` | ||
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| In the example above, the second expected statement uses pattern matching through a regular expression | ||
| by using the `pattern:` prefix. | ||
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| #### Testing Locally | ||
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| Currently, only Natvis visualizations have been defined for the `smallvec` crate via `debug_metadata/smallvec.natvis`, | ||
| which means the `tests/debugger_visualizer.rs` tests need to be run on Windows using the `*-pc-windows-msvc` targets. | ||
| To run these tests locally, first ensure the debugging tools for Windows are installed or install them following | ||
| the steps listed here, [Debugging Tools for Windows](https://docs.microsoft.com/en-us/windows-hardware/drivers/debugger/). | ||
| Once the debugging tools have been installed, the tests can be run in the same manner as they are in the CI | ||
| pipeline. | ||
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| #### Note | ||
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| When running the debugger visualizer tests, `tests/debugger_visualizer.rs`, they need to be run consecutively | ||
| and not in parallel. This can be achieved by passing the flag `--test-threads=1` to rustc. This is due to | ||
| how the debugger tests are run. Each test marked with the `#[debugger_test]` attribute launches a debugger | ||
| and attaches it to the current test process. If tests are running in parallel, the test will try to attach | ||
| a debugger to the current process which may already have a debugger attached causing the test to fail. | ||
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| For example: | ||
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| ``` | ||
| cargo test --test debugger_visualizer --features debugger_visualizer -- --test-threads=1 | ||
| ``` |
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| Original file line number | Diff line number | Diff line change |
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| <AutoVisualizer xmlns="http://schemas.microsoft.com/vstudio/debugger/natvis/2010"> | ||
| <Type Name="smallvec::SmallVec<array$<*,*>>" Priority="Medium"> | ||
| <Intrinsic Name="is_inline" Expression="$T2 > capacity" /> | ||
| <Intrinsic Name="len" Expression="is_inline() ? capacity : data.variant1.value.__0.__1" /> | ||
| <Intrinsic Name="data_ptr" Expression="is_inline() ? data.variant0.value.__0.value.value : data.variant1.value.__0.__0" /> | ||
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| <DisplayString>{{ len={len()} }}</DisplayString> | ||
| <Expand> | ||
| <Item Name="[capacity]">is_inline() ? $T2 : capacity</Item> | ||
| <Item Name="[len]">len()</Item> | ||
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| <ArrayItems> | ||
| <Size>len()</Size> | ||
| <ValuePointer>data_ptr()</ValuePointer> | ||
| </ArrayItems> | ||
| </Expand> | ||
| </Type> | ||
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| <Type Name="smallvec::SmallVec<array$<*,*>>" Priority="MediumLow"> | ||
| <Intrinsic Name="is_inline" Expression="$T2 > capacity" /> | ||
| <Intrinsic Name="len" Expression="is_inline() ? capacity : data.heap.__1" /> | ||
| <Intrinsic Name="data_ptr" Expression="is_inline() ? data.inline.value.value.value : data.heap.__0" /> | ||
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| <DisplayString>{{ len={len()} }}</DisplayString> | ||
| <Expand> | ||
| <Item Name="[capacity]">is_inline() ? $T2 : capacity</Item> | ||
| <Item Name="[len]">len()</Item> | ||
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| <ArrayItems> | ||
| <Size>len()</Size> | ||
| <ValuePointer>data_ptr()</ValuePointer> | ||
| </ArrayItems> | ||
| </Expand> | ||
| </Type> | ||
| </AutoVisualizer> |
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| Original file line number | Diff line number | Diff line change |
|---|---|---|
| @@ -0,0 +1,68 @@ | ||
| use debugger_test::debugger_test; | ||
| use smallvec::{smallvec, SmallVec}; | ||
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| #[inline(never)] | ||
| fn __break() {} | ||
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| #[debugger_test( | ||
| debugger = "cdb", | ||
| commands = r#" | ||
| .nvlist | ||
| dx sv | ||
| g | ||
| dx sv | ||
| g | ||
| dx sv | ||
| "#, | ||
| expected_statements = r#" | ||
| sv : { len=0x2 } [Type: smallvec::SmallVec<array$<i32,4> >] | ||
| [<Raw View>] [Type: smallvec::SmallVec<array$<i32,4> >] | ||
| [capacity] : 4 | ||
| [len] : 0x2 [Type: unsigned __int64] | ||
| [0] : 1 [Type: int] | ||
| [1] : 2 [Type: int] | ||
| sv : { len=0x5 } [Type: smallvec::SmallVec<array$<i32,4> >] | ||
| [<Raw View>] [Type: smallvec::SmallVec<array$<i32,4> >] | ||
| [capacity] : 0x8 [Type: unsigned __int64] | ||
| [len] : 0x5 [Type: unsigned __int64] | ||
| [0] : 5 [Type: int] | ||
| [1] : 2 [Type: int] | ||
| [2] : 3 [Type: int] | ||
| [3] : 4 [Type: int] | ||
| [4] : 5 [Type: int] | ||
| sv : { len=0x5 } [Type: smallvec::SmallVec<array$<i32,4> >] | ||
| [<Raw View>] [Type: smallvec::SmallVec<array$<i32,4> >] | ||
| [capacity] : 0x8 [Type: unsigned __int64] | ||
| [len] : 0x5 [Type: unsigned __int64] | ||
| [0] : 2 [Type: int] | ||
| [1] : 3 [Type: int] | ||
| [2] : 4 [Type: int] | ||
| [3] : 5 [Type: int] | ||
| [4] : 5 [Type: int] | ||
| "# | ||
| )] | ||
| #[inline(never)] | ||
| fn test_debugger_visualizer() { | ||
| // This SmallVec can hold up to 4 items on the stack: | ||
| let mut sv: SmallVec<[i32; 4]> = smallvec![1, 2]; | ||
| __break(); | ||
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| // Overfill the SmallVec to move its contents to the heap | ||
| for i in 3..6 { | ||
| sv.push(i); | ||
| } | ||
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| // Update the contents of the first value of the SmallVec. | ||
| sv[0] = sv[1] + sv[2]; | ||
| __break(); | ||
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| // Sort the SmallVec in place. | ||
| sv.sort(); | ||
| __break(); | ||
| } |