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Lint casting signed integers smaller than isize to raw pointers #43641

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Lint casting signed integers smaller than isize to raw pointers #43641

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oli-obk
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@oli-obk oli-obk commented Aug 4, 2017

cc #43291 (keeping open as tracking issue)

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r? @eddyb

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eddyb commented Aug 4, 2017

Whoa whoa what is all this new code? I expected a trivial check to be used only for a cargobomb run.

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eddyb commented Aug 4, 2017

cc @rust-lang/compiler

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oli-obk commented Aug 4, 2017

This code exists so we don't produce a suggestion like 5 + 6 as usize as *const T if we had (5 + 6) as *const T when starting out. It is 1:1 copied from clippy.

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eddyb commented Aug 4, 2017

It is 1:1 copied from clippy.

Ah, great! Would've been less surprising to see that in the PR description. However, I'd still start small, with an error-by-default lint with no interesting suggestions, for cargobomb.

@oli-obk oli-obk force-pushed the truncating_for_fun_and___wait_what branch from 2bea2ab to 84bed45 Compare August 4, 2017 11:56
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oli-obk commented Aug 4, 2017

done

eddyb
eddyb reviewed Aug 4, 2017
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src/test/run-pass/mir_misc_casts.rs Outdated
@@ -120,7 +120,7 @@ fn from_1i8()
let c10 = 1_i8 as u64;
let c11 = 1_i8 as f32;
let c12 = 1_i8 as f64;
let c13 = 1_i8 as *const libc::FILE;
let c13 = 1_i8 as isize as *const libc::FILE;
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The correct cast btw is through usize. Although... I'd leave the tests unchanged and just allow the lint in them.

ollie27
ollie27 reviewed Aug 4, 2017
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There is some overlap between this and #43339 btw.

src/librustc_lint/builtin.rs Outdated
ty::TyInt(ast::IntTy::Is) => return,
ty::TyInt(ast::IntTy::I128) |
ty::TyInt(ast::IntTy::I64) => {
if cx.tcx.data_layout.pointer_size.bytes() >= 8 {
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This doesn't seem right. I think this should be <= and the if needs to be part of the match pattern to allow this to fall through:

ty::TyInt(ast::IntTy::I128) |
ty::TyInt(ast::IntTy::I64) if cx.tcx.data_layout.pointer_size.bytes() <= 8 => {
    return;
},
ty::TyInt(ast::IntTy::I32) if cx.tcx.data_layout.pointer_size.bytes() <= 4 => {
    return;
},
ty::TyInt(ast::IntTy::I16) if cx.tcx.data_layout.pointer_size.bytes() <= 2 => {
    return;
},

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thanks! you're right of course, I got the logic reversed.

ollie27
ollie27 reviewed Aug 4, 2017
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src/librustc_lint/builtin.rs Outdated
// these we report
ty::TyInt(_) => {},
// only int casts are relevant
_ => {},
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I assume there's supposed to be a return here.

@shepmaster shepmaster added the S-waiting-on-crater Status: Waiting on a crater run to be completed. label Aug 4, 2017
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@eddyb I assume you will be starting the cargobomb?

frewsxcv added a commit to rust-lang/book that referenced this pull request Aug 4, 2017
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Casting from a pointer should have type 'isize', not 'i32'.
79b6ba1 
Found via rust-lang/rust#43641.
@frewsxcv frewsxcv mentioned this pull request Aug 4, 2017
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frewsxcv commented Aug 4, 2017

Looks like there's an error in the book. I opened a PR upstream: rust-lang/book#866.

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frewsxcv commented Aug 5, 2017

Upstream PR has merged. Updating the in-tree book submodule now: #43688.

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oli-obk commented Aug 5, 2017

Thanks for taking care of that!

@oli-obk oli-obk changed the title Lint casting integers other than isize/usize to raw pointers Lint casting signed integers smaller than isize to raw pointers Aug 5, 2017
carols10cents pushed a commit to frewsxcv/rust that referenced this pull request Aug 5, 2017
@frewsxcv @carols10cents
Bump 'src/doc/book' git submodule.
abc76ae 
Primarily to pick up this change:

rust-lang/book#866

...to move this PR forward:

rust-lang#43641
bors added a commit that referenced this pull request Aug 5, 2017
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Auto merge of #43688 - frewsxcv:frewsxcv-bump-book, r=carols10cents
dd1df35 
Bump 'src/doc/book' git submodule.

Primarily to pick up this change:

rust-lang/book#866

...to move this PR forward:

#43641
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frewsxcv commented Aug 6, 2017

@oli-obk the book should be good now, you should rebase or merge in master

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eddyb commented Aug 6, 2017

@frewsxcv Always rebase 😛!

@oli-obk oli-obk force-pushed the truncating_for_fun_and___wait_what branch from ca5681e to 72c77e9 Compare August 7, 2017 06:44
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oli-obk commented Aug 10, 2017

ping @eddyb

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eddyb commented Aug 10, 2017

@bors try

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bors commented Aug 10, 2017

⌛ Trying commit 72c77e9 with merge a1b0d1d...

bors added a commit that referenced this pull request Aug 10, 2017
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Auto merge of #43641 - oli-obk:truncating_for_fun_and___wait_what, r=…
a1b0d1d 
…<try>

Lint casting signed integers smaller than `isize` to raw pointers

cc #43291 (keeping open as tracking issue)
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bors commented Aug 10, 2017

☀️ Test successful - status-travis
State: approved= try=True

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eddyb commented Aug 10, 2017

cc @rust-lang/infra Cargobomb crater requested.

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aidanhs commented Aug 10, 2017

I'll get this cargobomb run going.

@RalfJung RalfJung mentioned this pull request Aug 10, 2017
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aidanhs commented Aug 14, 2017

Cargobomb run failed, the disk filled up because I failed to do due diligence on disk space beforehand - sorry! I'll prepare a new run now.

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aidanhs commented Aug 18, 2017

Cargobomb complete: http://cargobomb-reports.s3.amazonaws.com/pr-43641/index.html

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oli-obk commented Aug 18, 2017 •
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I'll check the ones below once there's a PR against them

  • cargo-tarpaulin-0.3.13: ptrace(PTRACE_CONT, pid, ptr::null_mut(), (s as i32) as * mut c_void)
  • drm-rs-0.1.3:ffi::xf86drm_mode::drmModePageFlip(fd, crtc_id, fb_id, flags, user_data as *const _)
  • egl-0.2.7:ffi::eglGetConfigs(display, list.configs, config_size, list.count as *mut int32_t)
  • freertos_rs-0.1.0:pub fn freertos_rs_create_recursive_mutex() -> FreeRtosQueueHandle { 1 as _ }
  • nix-0.8.1, nix-0.9.0:ptrace(PTRACE_SETOPTIONS, pid, ptr::null_mut(), options as *mut c_void).map(drop)
  • rsjs-0.1.2:let ptr = js_int!("return RSJS.storeObject(RSJS.copyStringToHeap(RSJS.loadObject($0)));", obj) as *mut u16;
  • tracetree-0.1.5:let data = signal.map(|s| s as i32 as *mut c_void).unwrap_or(ptr::null_mut());
  • winit-0.7.5:ffi::CopyFromParent as *mut _ and self.x.screen_id as *mut libc::c_void
  • https://github.com/xd009642/tarpaulin#2c26a87cb45324289196280ac4b852793b8916de:ptrace(PTRACE_CONT, pid, ptr::null_mut(), (s as i32) as * mut c_void)

irrelevant failures

  • grnenv-rs-0.2.0: got /home/cargobomb/.groonga expected /home/grnenv/groonga
  • hashconsing-0.3.0: some runtime test failure
  • hyper-timeout-connector-0.1.0: can't access network during tests
  • librocksdb-sys-0.4.1: empty cargobomb output
  • milagro-crypto-0.1.14: unknown error during testing
  • netlib-src-0.7.0: empty cargobomb output
  • nss-sys-0.1.9: unknown error
  • owapi-0.1.0: runtime test failure
  • rocksdb-0.7.0: empty cargobomb output
  • simple-munin-plugin-0.1.0: runtime test failure
  • theban_interval_tree-0.7.1: runtime test failure
  • timekeeper-0.2.4: runtime test failure
  • tokio-proto-0.1.1: runtime test failure
  • vidar-0.1.0: runtime test failure
  • https://github.com/tinco/rust-static_any_map#909025e6146137938d43fd01b2f715a990358662: runtime test failure
  • https://github.com/vks/mpw-rs#d1ac69b31292245e9b48a3b267dd85720e46a53d: empty cargobomb output

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eddyb commented Aug 18, 2017 •
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@oli-obk So the thing we were worried about was whether any of these would need the (buggy) zero-extension behavior, to know if we can just fix it right away.
Specifically, if there are negative integers, less wide than pointers, being cast to pointers.
EDIT: exempt from that are cases where the C side truncates back to the small integer width.

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oli-obk commented Aug 18, 2017

I have checked everything but rsjs for which I was not able to find a repository. None of them actually depend on the buggy casting, since they only have positive values or 0.

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oli-obk commented Aug 21, 2017

Closing in favour of simply making the backwards incompatible fix

@oli-obk oli-obk closed this Aug 21, 2017
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@oli-obk oli-obk deleted the truncating_for_fun_and___wait_what branch June 15, 2020 15:26
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