LLVM assertion failed: conflicting locations for variable

[tomaka]

To reproduce, just clone this repo: https://github.com/tomaka/rustc-issue-repro (it's a stripped down version of my project)

cargo build should trigger:

Assertion failed: std::all_of(Expr.begin(), Expr.end(), [](const DIExpression *E) { return E && E->isBitPiece(); }) && "conflicting locations for variable", file c:\bot\slave\nightly-dist-rustc-win-msvc-64\build\src\llvm\lib\codegen\asmprinter\DwarfDebug.h, line 154

This is with the MSVC 64bits nightly from a few days ago.

The only clue that I have is that here if you replace the call to VertexBuffer::immutable with unsafe { ::std::mem::zeroed() }, it fixes the problem.

The problematic call graph is:

• https://github.com/tomaka/rustc-issue-repro/blob/ef9ae6f89140143b74e902830d114a6d0b2fc357/src/main.rs#L34
• https://github.com/tomaka/rustc-issue-repro/blob/ef9ae6f89140143b74e902830d114a6d0b2fc357/src/game_scene/scene.rs#L35
• https://github.com/tomaka/rustc-issue-repro/blob/ef9ae6f89140143b74e902830d114a6d0b2fc357/src/game_scene/view.rs#L33
• https://github.com/tomaka/rustc-issue-repro/blob/ef9ae6f89140143b74e902830d114a6d0b2fc357/src/game_scene/models.rs#L22

[tomaka]

Note that I have enabled 2 codegen units (https://github.com/tomaka/rustc-issue-repro/blob/master/Cargo.toml#L8), but it's also buggy even without that line.

Using opt-level 0 fixes it however.

[michaelwoerister]

I can reproduce this on Linux.

[michaelwoerister]

I have not had the time to really debug into this but my hunch is that LLVM messes up the debuginfo during optimization. This might still be a problem of rustc producing LLVM IR that is not quite valid.

[brson]

@michaelwoerister you might check out whether this is still an issue sometime.

[michaelwoerister]

Yes, let's hope that a year of LLVM progress has solved this...

[steveklabnik]

I cannot reproduce, but for unrelated reasons:

error: Could not compile `rustc-serialize`.
warning: build failed, waiting for other jobs to finish...
error[E0592]: duplicate definitions with name `item`
    --> C:\Users\Steve Klabnik\.cargo\registry\src\github.com-1ecc6299db9ec823\winapi-0.2.4\src\macros.rs:134:13
     |
134  |                pub unsafe fn $variant(&self) -> &$fieldtype {
     |   _____________-
     |  |_____________|
     | ||
135  | ||                 ::std::mem::transmute(&self.$field)
136  | ||             }
     | ||             -
     | ||_____________|
     | |______________duplicate definitions for `item`
     |                other definition for `item`
     |
    ::: C:\Users\Steve Klabnik\.cargo\registry\src\github.com-1ecc6299db9ec823\winapi-0.2.4\src\commctrl.rs:2889:1
     |
2889 |    UNION!(TVINSERTSTRUCTA, itemex, item, item_mut, TV_ITEMA);
     |    ---------------------------------------------------------- in this macro invocation

error[E0592]: duplicate definitions with name `item_mut`
    --> C:\Users\Steve Klabnik\.cargo\registry\src\github.com-1ecc6299db9ec823\winapi-0.2.4\src\macros.rs:138:13
     |
138  |                pub unsafe fn $variantmut(&mut self) -> &mut $fieldtype {
     |   _____________-
     |  |_____________|
     | ||
139  | ||                 ::std::mem::transmute(&mut self.$field)
140  | ||             }
     | ||             -
     | ||_____________|
     | |______________duplicate definitions for `item_mut`
     |                other definition for `item_mut`
     |
    ::: C:\Users\Steve Klabnik\.cargo\registry\src\github.com-1ecc6299db9ec823\winapi-0.2.4\src\commctrl.rs:2889:1
     |
2889 |    UNION!(TVINSERTSTRUCTA, itemex, item, item_mut, TV_ITEMA);
     |    ---------------------------------------------------------- in this macro invocation

error: aborting due to 2 previous errors