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refactor: Fixed all the lines exceeding more than 80 characters

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cg-cnu 2018-04-09 22:27:43 +05:30 committed by Who? Me?!
parent d4bc8827f8
commit 3814a2eeef
1 changed files with 41 additions and 17 deletions
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src/compiler-debugging.md
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@ -17,7 +17,9 @@ normal Rust programs. IIRC backtraces **don't work** on Mac and on MinGW,
sorry. If you have trouble or the backtraces are full of `unknown`, sorry. If you have trouble or the backtraces are full of `unknown`,
you might want to find some way to use Linux or MSVC on Windows. you might want to find some way to use Linux or MSVC on Windows.
In the default configuration, you don't have line numbers enabled, so the backtrace looks like this: In the default configuration, you don't have line numbers enabled, so the
backtrace looks like this:
``` ```
stack backtrace: stack backtrace:
0: std::sys::imp::backtrace::tracing::imp::unwind_backtrace 0: std::sys::imp::backtrace::tracing::imp::unwind_backtrace
@ -26,7 +28,8 @@ stack backtrace:
3: std::panicking::default_hook 3: std::panicking::default_hook
4: std::panicking::rust_panic_with_hook 4: std::panicking::rust_panic_with_hook
5: std::panicking::begin_panic 5: std::panicking::begin_panic
6: rustc_typeck::check::cast::<impl rustc_typeck::check::FnCtxt<'a, 'gcx, 'tcx>>::pointer_kind 6: rustc_typeck::check::cast::<impl rustc_typeck::check::FnCtxt<'a, 'gcx, \
'tcx>>::pointer_kind
(~~~~ LINES REMOVED BY ME FOR BREVITY ~~~~) (~~~~ LINES REMOVED BY ME FOR BREVITY ~~~~)
32: rustc_typeck::check_crate 32: rustc_typeck::check_crate
33: <std::thread::local::LocalKey<T>>::with 33: <std::thread::local::LocalKey<T>>::with
@ -36,11 +39,15 @@ stack backtrace:
37: rustc_driver::run_compiler 37: rustc_driver::run_compiler
``` ```
If you want line numbers for the stack trace, you can enable `debuginfo-lines=true` or `debuginfo=true` in your config.toml and rebuild the compiler. Then the backtrace will look like this: If you want line numbers for the stack trace, you can enable
`debuginfo-lines=true` or `debuginfo=true` in your config.toml and rebuild the
compiler. Then the backtrace will look like this:
``` ```
stack backtrace: stack backtrace:
(~~~~ LINES REMOVED BY ME FOR BREVITY ~~~~) (~~~~ LINES REMOVED BY ME FOR BREVITY ~~~~)
6: rustc_typeck::check::cast::<impl rustc_typeck::check::FnCtxt<'a, 'gcx, 'tcx>>::pointer_kind 6: rustc_typeck::check::cast::<impl rustc_typeck::check::FnCtxt<'a, 'gcx, \
'tcx>>::pointer_kind
at /home/user/rust/src/librustc_typeck/check/cast.rs:110 at /home/user/rust/src/librustc_typeck/check/cast.rs:110
7: rustc_typeck::check::cast::CastCheck::check 7: rustc_typeck::check::cast::CastCheck::check
at /home/user/rust/src/librustc_typeck/check/cast.rs:572 at /home/user/rust/src/librustc_typeck/check/cast.rs:572
@ -104,13 +111,17 @@ note: rustc 1.24.0-dev running on x86_64-unknown-linux-gnu
note: run with `RUST_BACKTRACE=1` for a backtrace note: run with `RUST_BACKTRACE=1` for a backtrace
thread 'rustc' panicked at 'encountered error with `-Z treat_err_as_bug', /home/user/rust/src/librustc_errors/lib.rs:411:12 thread 'rustc' panicked at 'encountered error with `-Z treat_err_as_bug',
note: Some details are omitted, run with `RUST_BACKTRACE=full` for a verbose backtrace. /home/user/rust/src/librustc_errors/lib.rs:411:12
note: Some details are omitted, run with `RUST_BACKTRACE=full` for a verbose
backtrace.
stack backtrace: stack backtrace:
(~~~ IRRELEVANT PART OF BACKTRACE REMOVED BY ME ~~~) (~~~ IRRELEVANT PART OF BACKTRACE REMOVED BY ME ~~~)
7: rustc::traits::error_reporting::<impl rustc::infer::InferCtxt<'a, 'gcx, 'tcx>>::report_selection_error 7: rustc::traits::error_reporting::<impl rustc::infer::InferCtxt<'a, 'gcx,
'tcx>>::report_selection_error
at /home/user/rust/src/librustc/traits/error_reporting.rs:823 at /home/user/rust/src/librustc/traits/error_reporting.rs:823
8: rustc::traits::error_reporting::<impl rustc::infer::InferCtxt<'a, 'gcx, 'tcx>>::report_fulfillment_errors 8: rustc::traits::error_reporting::<impl rustc::infer::InferCtxt<'a, 'gcx,
'tcx>>::report_fulfillment_errors
at /home/user/rust/src/librustc/traits/error_reporting.rs:160 at /home/user/rust/src/librustc/traits/error_reporting.rs:160
at /home/user/rust/src/librustc/traits/error_reporting.rs:112 at /home/user/rust/src/librustc/traits/error_reporting.rs:112
9: rustc_typeck::check::FnCtxt::select_obligations_where_possible 9: rustc_typeck::check::FnCtxt::select_obligations_where_possible
@ -190,18 +201,28 @@ However, there are still a few concerns that you might care about:
### Expensive operations in logs ### Expensive operations in logs
A note of caution: the expressions *within* the `debug!` call are run A note of caution: the expressions *within* the `debug!` call are run
whenever RUST_LOG is set, even if the filter would exclude the log. This means that if in the module `rustc::foo` you have a statement whenever RUST_LOG is set, even if the filter would exclude the log. This means
that if in the module `rustc::foo` you have a statement
```Rust ```Rust
debug!("{:?}", random_operation(tcx)); debug!("{:?}", random_operation(tcx));
``` ```
Then if someone runs a debug `rustc` with `RUST_LOG=rustc::bar`, then `random_operation()` will still run - even while it's output will never be needed! Then if someone runs a debug `rustc` with `RUST_LOG=rustc::bar`, then
`random_operation()` will still run - even while it's output will never be
needed!
This means that you should not put anything too expensive or likely This means that you should not put anything too expensive or likely
to crash there - that would annoy anyone who wants to use logging for their own module. Note that if `RUST_LOG` is unset (the default), then the code will not run - this means that if your logging code panics, then no-one will know it until someone tries to use logging to find *another* bug. to crash there - that would annoy anyone who wants to use logging for their own
module. Note that if `RUST_LOG` is unset (the default), then the code will not
run - this means that if your logging code panics, then no-one will know it
until someone tries to use logging to find *another* bug.
If you *need* to do an expensive operation in a log, be aware that while log expressions are *evaluated* even if logging is not enabled in your module, they are not *formatted* unless it *is*. This means you can put your expensive/crashy operations inside an `fmt::Debug` impl, and they will not be run unless your log is enabled: If you *need* to do an expensive operation in a log, be aware that while log
expressions are *evaluated* even if logging is not enabled in your module,
they are not *formatted* unless it *is*. This means you can put your
expensive/crashy operations inside an `fmt::Debug` impl, and they will not be
run unless your log is enabled:
```Rust ```Rust
use std::fmt; use std::fmt;
@ -225,8 +246,8 @@ debug!("{:?}", ExpensiveOperationContainer { tcx });
## Formatting Graphviz output (.dot files) ## Formatting Graphviz output (.dot files)
[formatting-graphviz-output]: #formatting-graphviz-output [formatting-graphviz-output]: #formatting-graphviz-output
Some compiler options for debugging specific features yield graphviz graphs - e.g. Some compiler options for debugging specific features yield graphviz graphs -
the `#[rustc_mir(borrowck_graphviz_postflow="suffix.dot")]` attribute e.g. the `#[rustc_mir(borrowck_graphviz_postflow="suffix.dot")]` attribute
dumps various borrow-checker dataflow graphs. dumps various borrow-checker dataflow graphs.
These all produce `.dot` files. To view these files, install graphviz (e.g. These all produce `.dot` files. To view these files, install graphviz (e.g.
@ -252,7 +273,8 @@ assertions enabled - either an "alt" nightly or a compiler you build yourself
by setting `[llvm] assertions=true` in your config.toml - and by setting `[llvm] assertions=true` in your config.toml - and
see whether anything turns up. see whether anything turns up.
The rustc build process builds the LLVM tools into `./build/<host-triple>/llvm/bin`. They can be called directly. The rustc build process builds the LLVM tools into
`./build/<host-triple>/llvm/bin`. They can be called directly.
The default rustc compilation pipeline has multiple codegen units, which is hard The default rustc compilation pipeline has multiple codegen units, which is hard
to replicate manually and means that LLVM is called multiple times in parallel. to replicate manually and means that LLVM is called multiple times in parallel.
@ -262,7 +284,8 @@ passing `-C codegen-units=1` to rustc will make debugging easier.
If you want to play with the optimization pipeline, you can use the `opt` from If you want to play with the optimization pipeline, you can use the `opt` from
there on the IR rustc emits with `--emit=llvm-ir`. Note there on the IR rustc emits with `--emit=llvm-ir`. Note
that rustc emits different IR depending on whether `-O` is enabled, even without that rustc emits different IR depending on whether `-O` is enabled, even without
LLVM's optimizations, so if you want to play with the IR rustc emits, you should: LLVM's optimizations, so if you want to play with the IR rustc emits,
you should:
``` ```
$ rustc +local my-file.rs --emit=llvm-ir -O -C no-prepopulate-passes \ $ rustc +local my-file.rs --emit=llvm-ir -O -C no-prepopulate-passes \
-C codegen-units=1 -C codegen-units=1
@ -275,7 +298,8 @@ IR causes an optimization-time assertion to fail, or to see when
LLVM performs a particular optimization, you can pass the rustc flag LLVM performs a particular optimization, you can pass the rustc flag
`-C llvm-args=-print-after-all`, and possibly add `-C llvm-args=-print-after-all`, and possibly add
`-C llvm-args='-filter-print-funcs=EXACT_FUNCTION_NAME` (e.g. `-C llvm-args='-filter-print-funcs=EXACT_FUNCTION_NAME` (e.g.
`-C llvm-args='-filter-print-funcs=_ZN11collections3str21_$LT$impl$u20$str$GT$7replace17hbe10ea2e7c809b0bE'`). `-C llvm-args='-filter-print-funcs=_ZN11collections3str21_$LT$impl$u20$str$GT$\
7replace17hbe10ea2e7c809b0bE'`).
That produces a lot of output into standard error, so you'll want to pipe That produces a lot of output into standard error, so you'll want to pipe
that to some file. Also, if you are using neither `-filter-print-funcs` nor that to some file. Also, if you are using neither `-filter-print-funcs` nor