The default ThinLTO pre-link pipeline does not include optimizer last
extension points. Thus, when using the new LLVM pass manager & ThinLTO
& sanitizers on any opt-level different from zero, the sanitizer
function passes would be omitted from the pipeline.
Add optimizer last extensions points manually to the pipeline, but guard
registration with stage check in the case this behaviour changes in the
future.
Support new LLVM pass manager
Add support for the new LLVM pass manager behind a `-Z new-llvm-pass-manager=on` option. Both the pre-link optimization and LTO pipelines use the new pass manager. There's some bits that are not supported yet:
* `-C passes`. NewPM requires an entirely different way of specifying custom pass pipelines. We should probably expose that functionality, but it doesn't directly map to what `-C passes` does.
* NewPM has no support for custom inline parameters right now. We'd have to add upstream support for that first.
* NewPM does not support PGO at O0 in LLVM 9 (which is why those tests fail with NewPM enabled). This is supported in LLVM 10.
* NewPM does not support MergeFunctions in LLVM 9. I've landed this upstream just before the cut, so we'll be able to re-enable that with LLVM 10.
Closes#64289.
r? @ghost
Enable use-after-scope checks by default when using AddressSanitizer.
They allow to detect incorrect use of stack objects after their scope
have already ended. The detection is based on LLVM lifetime intrinsics.
To facilitate the use of this functionality, the lifetime intrinsics are
now emitted regardless of optimization level if enabled sanitizer makes
use of them.
Migrate to LLVM{Get,Set}ValueName2
The deprecated `LLVM{Get,Set}ValueName` only work with NUL-terminated
strings, but the `2` variants use explicit lengths, which fits better
with Rust strings and slices. We now use these in new helper functions
`llvm::{get,set}_value_name` that convert to/from `&[u8]`.
Closes#64223.
r? @rkruppe
Use Module::print() instead of a PrintModulePass
llvm::Module has a print() method. It is unnecessary to create a pass just for the purpose of printing LLVM IR.
The deprecated `LLVM{Get,Set}ValueName` only work with NUL-terminated
strings, but the `2` variants use explicit lengths, which fits better
with Rust strings and slices. We now use these in new helper functions
`llvm::{get,set}_value_name` that convert to/from `&[u8]`.
Update the minimum external LLVM to 7
LLVM 7 is over a year old, which should be plenty for compatibility. The
last LLVM 6 holdout was llvm-emscripten, which went away in #65501.
I've also included a fix for LLVM 8 lacking `MemorySanitizerOptions`,
which was broken by #66522.
For SGX, the relocation using the relocation table is done by
the code in rust/src/libstd/sys/sgx/abi/reloc.rs and this code
should not require relocation. Setting RelaxELFRelocations flag
if allows this to happen, hence adding a Target Option for it.
LLVM 7 is over a year old, which should be plenty for compatibility. The
last LLVM 6 holdout was llvm-emscripten, which went away in #65501.
I've also included a fix for LLVM 8 lacking `MemorySanitizerOptions`,
which was broken by #66522.
Use LLVMDisposePassManager instead of raw delete in rustllvm
LLVM has a dedicated API call which wraps the destructor invocation for the PassManager.
Rust invokes it [otherwhere](https://github.com/rust-lang/rust/blob/d63b24ffcc48f44ef09e0369e6516d6f2dec3520/src/librustc_codegen_llvm/back/write.rs#L446-L447), but not in the `LLVMRustWriteOutputFile`.
Since `LLVMDisposePassManager` might be extended to perform additional cleanup actions in the future, this change replaces raw destructor invocation with that API call.
Configure LLVM module PIC level
As of LLVM 9, this is required for 32-bit PowerPC to properly generate
PLT references. Previously, only BigPIC was supported; now LLVM supports
both BigPIC and SmallPIC, and there is no default value provided.
Allow specifying LLVM's MCTargetOptions::ABIName in target specification files
This addresses #65024, as it allows RISC-V target specification files to set `"llvm-abiname": "lp64d"`.
Other languages (read: C) usually expose this codegen parameter under a compiler argument like `-mabi=<XYZ>`.
As of LLVM 9, this is required for 32-bit PowerPC to properly generate
PLT references. Previously, only BigPIC was supported; now LLVM supports
both BigPIC and SmallPIC, and there is no default value provided.
Just to make it useable for profiling and such inside
rustc itself. It was vaguely useful in
https://wiki.alopex.li/WhereRustcSpendsItsTime and I figured
I might as well upstream it; I may or may not ever get around
to doing more with it (hopefully I will), but it may be useful
for others.
This addresses #65024, as it allows RISC-V target specification
files to set "llvm-abiname": "lp64d". In general, it is useful
for the programmer to be able to set this codegen parameter,
which other languages usually expose under a compiler argument
like "-mabi=<XYZ>".
Exception for specific cases like linting, additional passes should
be going into the module pass manager (even if they are function
passes). The separate function pass manager is only used for very
early optimization passes.
Rather than apparending passes to the MPM, use the OptimizerLast
and EnabledOnOptLevel0 pass manager builder extension hooks, which
allow adding passes directly before finalization (alias
canonicalization and name-anon-globals).
The main effect and purpose of this change is to add sanitizer
passes at the end of the pipeline, which is where they belong.
In LLVM 9 the address sanitizer can't be used as a pass in the
early function pass manager, because it has a dependence on a
module-level analysis pass.
Vadim Petrochenkov