trans: don't ICE when trying to create ADT trans-items
ADTs are translated in-place from rustc_trans::callee, so no trans-items
are needed.
This fix will be superseded by the shimmir branch, but I prefer not to
backport that to beta.
Fixes#39823.
Beta-nominating because regression.
r? @michaelwoerister
add `-C overflow-checks` option
In addition to defining and handling the new option, we also add a method on librustc::Session for determining the necessity of overflow checks. This method provides a single point to sort out the three (!) different ways for turning on overflow checks: -C debug-assertions, -C overflow-checks, and -Z force-overflow-checks.
I was seeing a [run-pass/issue-28950.rs](b1363a73ed/src/test/run-pass/issue-28950.rs) failure on my machine with these patches, but I was also seeing the failure without the changes to the core compiler. We'll see what travis says.
Fixes#33134. r? @alexcrichton
Set metadata for vtable-related loads
Give LLVM much more information about vtable pointers. Without the extra
information, LLVM has to be rather pessimistic about vtables, preventing
a number of obvious optimisations.
* Makes the vtable pointer argument noalias and readonly.
* Marks loads of the vtable pointer as nonnull.
* Marks load from the vtable with `!invariant.load` metadata.
Fixes#39992
ADTs are translated in-place from rustc_trans::callee, so no trans-items
are needed.
This fix will be superseded by the shimmir branch, but I prefer not to
backport that to beta.
Fixes#39823.
In addition to defining and handling the new option, we also add a
method on librustc::Session for determining the necessity of overflow
checks. This method provides a single point to sort out the three (!)
different ways for turning on overflow checks: -C debug-assertions, -C
overflow-checks, and -Z force-overflow-checks.
Fixes#33134.
Give LLVM much more information about vtable pointers. Without the extra
information, LLVM has to be rather pessimistic about vtables, preventing
a number of obvious optimisations.
* Makes the vtable pointer argument noalias and readonly.
* Marks loads of the vtable pointer as nonnull.
* Marks load from the vtable with `!invariant.load` metadata.
Fixes#39992
When targeting Emscripten, rustc emits Vector Instructions by default.
However Web Assembly doesn't support Vector Instructions yet, which
causes Binaryen to fail converting the intermediate asm.js code to Web
Assembly. While asm.js kind of supports Vector Instructions, they
aren't supported by any browser other than Firefox, often meaning that
they need to be emulated very slowly. So it should just be turned off
for all Emscripten targets.
Fixes#38558
erase late bound regions in `get_vtable_methods()`
Higher-ranked object types can otherwise cause late-bound regions to
sneak into the substs, leading to the false conclusion that some method
is unreachable.
r? @arielb1, who wrote the heart of this patch anyhow
Fixes#39292
Higher-ranked object types can otherwise cause late-bound regions to
sneak into the substs, leading to the false conclusion that some method
is unreachable. The heart of this patch is from @arielb1.
[MIR] SwitchInt Everywhere
Something I've been meaning to do for a very long while. This PR essentially gets rid of 3 kinds of conditional branching and only keeps the most general one - `SwitchInt`. Primary benefits are such that dealing with MIR now does not involve dealing with 3 different ways to do conditional control flow. On the other hand, constructing a `SwitchInt` currently requires more code than what previously was necessary to build an equivalent `If` terminator. Something trivially "fixable" with some constructor methods somewhere (MIR needs stuff like that badly in general).
Some timings (tl;dr: slightly faster^1 (unexpected), but also uses slightly more memory at peak (expected)):
^1: Not sure if the speed benefits are because of LLVM liking the generated code better or the compiler itself getting compiled better. Either way, its a net benefit. The CORE and SYNTAX timings done for compilation without optimisation.
```
AFTER:
Building stage1 std artifacts (x86_64-unknown-linux-gnu -> x86_64-unknown-linux-gnu)
Finished release [optimized] target(s) in 31.50 secs
Finished release [optimized] target(s) in 31.42 secs
Building stage1 compiler artifacts (x86_64-unknown-linux-gnu -> x86_64-unknown-linux-gnu)
Finished release [optimized] target(s) in 439.56 secs
Finished release [optimized] target(s) in 435.15 secs
CORE: 99% (24.81 real, 0.13 kernel, 24.57 user); 358536k resident
CORE: 99% (24.56 real, 0.15 kernel, 24.36 user); 359168k resident
SYNTAX: 99% (49.98 real, 0.48 kernel, 49.42 user); 653416k resident
SYNTAX: 99% (50.07 real, 0.58 kernel, 49.43 user); 653604k resident
BEFORE:
Building stage1 std artifacts (x86_64-unknown-linux-gnu -> x86_64-unknown-linux-gnu)
Finished release [optimized] target(s) in 31.84 secs
Building stage1 compiler artifacts (x86_64-unknown-linux-gnu -> x86_64-unknown-linux-gnu)
Finished release [optimized] target(s) in 451.17 secs
CORE: 99% (24.66 real, 0.20 kernel, 24.38 user); 351096k resident
CORE: 99% (24.36 real, 0.17 kernel, 24.18 user); 352284k resident
SYNTAX: 99% (52.24 real, 0.56 kernel, 51.66 user); 645544k resident
SYNTAX: 99% (51.55 real, 0.48 kernel, 50.99 user); 646428k resident
```
cc @nikomatsakis @eddyb
This removes another special case of Switch by replacing it with the more general SwitchInt. While
this is more clunky currently, there’s no reason we can’t make it nice (and efficient) to use.
Previously AdtDef variants contained ConstInt for each discriminant, which did not really reflect
the actual type of the discriminants. Moving the type into AdtDef allows to easily put the type
into metadata and also saves bytes from ConstVal overhead for each discriminant.
Also arguably the code is cleaner now :)
It claims to accept most GNU linker options, but in fact most of them
have no effect and instead it requires some special options which are
easier to handle in a separate trait.
Currently added:
- `export_symbols`: works on executables as special Emscripten case
since staticlibs/dylibs aren't compiled to JS, while exports are
required to be accessible from JS.
Fixes#39171.
- `optimize` - translates Rust's optimization level to Emscripten
optimization level (whether passed via `-C opt-level=...` or `-O...`).
Fixes#36899.
- `debuginfo` - translates debug info; Emscripten has 5 debug levels
while Rust has 3, so chose to translate `-C debuginfo=1` to `-g3`
(preserves whitespace, variable and function names for easy debugging).
Fixes#36901.
- `no_default_libraries` - tells Emscripten to exlude `memcpy` and co.
Exclude top-level macro expansions from source location override.
It occurred to me that a simple heuristic can address the issue #36382: any macros that expand into items (including `include!()`) don't need to be stepped over because there's not code to step through above a function scope level.
r? @michaelwoerister
Choose different name for metadata obj-file to avoid clashes with user-chosen names.
Fixes#39585 and probably https://github.com/rust-lang/rust/issues/39508.
Incremental compilation assigns different names to obj-files than regular compilation. If a crate is called "metadata" this can lead to a clash between the root module's obj-file and the obj-file containing crate-metadata. This PR assigns a name to the metadata obj-file that cannot clash with other obj-file because it contains a `.` which is not allowed in a Rust module identifier.
r? @alexcrichton
cc @nikomatsakis
Emit DW_AT_main_subprogram
This changes rustc to emit DW_AT_main_subprogram on the "main" program.
This lets gdb suitably stop at the user's main in response to
"start" (rather than the library's main, which is what happens
currently).
Fixes#32620
r? michaelwoerister
emit "align 1" metadata on loads/stores of packed structs
According to the LLVM reference:
> A value of 0 or an omitted align argument means that the operation has
the ABI alignment for the target.
So loads/stores of fields of packed structs need to have their align set
to 1. Implement that by tracking the alignment of `LvalueRef`s.
Fixes#39376.
r? @eddyb
