Add debugging support

[emberian]

This is of course predicated on rustc emitting debuginfo (pdb?) that Visual Studio can understand, but there's nothing nicer than Visual Studio's debugger.

[michaelwoerister]

This might be of interest:
http://clang.llvm.org/docs/MSVCCompatibility.html#abi-features

LLVM seems to support some debuginfo generation on Windows at the moment, but only line tables, so you won't be able to inspect variables.

There's also cv2pdb which claims to be able to convert DWARF into PDB. I haven't tried it yet.

[vosen]

I've went and checked cv2pdb and it seems to be working fine with rust-compiled code: screenshot. Doesn't even require Visual Rust.
Bundling cv2pdb with our build package and adding it to the build script would be a good start, giving us some simple debugging capability.

[vosen]

Looks like Microsoft will be doing our work for us:
http://blogs.msdn.com/b/vcblog/archive/2015/04/29/open-sourcing-visual-studio-s-gdb-lldb-debug-engine.aspx

[randomPoison]

As of the 1.2 release the other day the 1.3 beta and 1.4 nightly have support for the msvc toolchain which emits a pdb. I've tested my project and I'm able to debug my project with VS.

[sunsided]

The MSVC ABI version of Rust for Windows indeed creates PDB files on build, however debugging doesn't seem to work with Visual Rust when F5-ing; breakpoints are ignored.

[Nuclearfossil]

New Rust coder and experiencing the same as @sunsided points out.

Visual Studio 2015, using a simple 'hello world' project.

[vosen]

With #199 debugging under MSVC ABI (both 32 and 64 bit) should work now.

[iliekturtles]

I'm using the latest AppVeyor build based off #200 and Rust stable 1.5 x86_64-pc-windows-msvc. The call stack and break points work (they worked in the November build as well) however watch windows don't work for variables. I'm using the Rust code below modified from the application template and compiling/running in debug mode and get identifier "xxx_this_is_my_symbol_xxx" is undefined in the watch window. Am I doing something wrong?

    let mut xxx_this_is_my_symbol_xxx = 5;
    println!("Hello, world! {}", xxx_this_is_my_symbol_xxx);
    xxx_this_is_my_symbol_xxx += 1;
    println!("Hello, world! {}", xxx_this_is_my_symbol_xxx);

[retep998]

Rust MSVC debug info is currently lacking due to LLVM being kinda awful at it still. It doesn't know how to emit debug info for local variables yet. You're not doing anything wrong, and there's not much Rust or VisualRust can do here other than wait for LLVM to get their act together.