In our current Rust world, we have the following dependency structure:
xul.so --------------------------+
|
xul-gtest.so -+--> xul.a --------+-> gkrust
|
+--> gkrust-gtest
This structure results in link errors with multiply-defined symbols
between gkrust-gtest and gkrust with newer Rust releases when linking
xul-gtest.so. So we have to do something different.
Our new structure is:
xul.so --------------------------+
|
xul-gtest.so -+--> xul.a --------+-> gkrust --+-> gkrust-shared
| |
+--> gkrust-gtest --------------+
and we enforce that a given shared library can only have at most one
Rust library that it depends on. Said Rust library is assumed to
include all significant Rust dependencies of the dependent static
libraries as well. (In the above structure, gkrust is simply a wrapper
around gkrust-shared, so gkrust-gtest doesn't have to include gkrust as
a dependency.)
For testing purposes it will be useful to be able to trigger crashes in Rust
code. Being able to trigger a panic seems like a good place to start. This
will make it easier to validate improvements in crash reporting.
MozReview-Commit-ID: Bh5rBieLLWW
This patch is really two separate changes.
The first change is that rust crates are large, standalone entities that
may contain multitudes of source files. It therefore doesn't make sense
to keep them in SOURCES, as we have been doing. Moving to use cargo
will require a higher-level approach, which suggests that we need a
different, higher-level representation for Rust sources in the build
system.
The representation here is to have the build system refer to things
defined in Cargo.toml files as the entities dealt with in the build
system, and let Cargo deal with the details of actually building things.
This approach means that adding a new crate to an existing library just
requires editing Rust and Cargo.toml files, rather than dealing with
moz.build, which seems more natural to Rust programmers. By having the
source files for libraries (and binaries in subsequent iterations of
this support) checked in to the tree, we can also take advantage of
Cargo.lock files.
The second is that we switch the core build system over to building via
cargo, rather than invoking rustc directly.
We also clean up a number of leftover things from the Old Way of doing
things. A number of tests are added to confirm that we'll only permit
crates to be built that have dependencies in-tree.
This patch is really two separate changes.
The first change is that rust crates are large, standalone entities that
may contain multitudes of source files. It therefore doesn't make sense
to keep them in SOURCES, as we have been doing. Moving to use cargo
will require a higher-level approach, which suggests that we need a
different, higher-level representation for Rust sources in the build
system.
The representation here is to have the build system refer to things
defined in Cargo.toml files as the entities dealt with in the build
system, and let Cargo deal with the details of actually building things.
This approach means that adding a new crate to an existing library just
requires editing Rust and Cargo.toml files, rather than dealing with
moz.build, which seems more natural to Rust programmers. By having the
source files for libraries (and binaries in subsequent iterations of
this support) checked in to the tree, we can also take advantage of
Cargo.lock files.
The second is that we switch the core build system over to building via
cargo, rather than invoking rustc directly.
We also clean up a number of leftover things from the Old Way of doing
things. A number of tests are added to confirm that we'll only permit
crates to be built that have dependencies in-tree.
