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.
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.
Clean up handling of `-Z pgo-gen` commandline option.
This PR adapts the `-Z pgo-gen` flag to how Clang and GCC handle the corresponding `-fprofile-generate` flag. In particular, the flag now optionally takes a directory to place the profiling data in and allows to omit the argument (instead of having to pass an empty string).
Exclude profiler-generated symbols from MSVC __imp_-symbol workaround.
LLVM's profiling instrumentation adds a few symbols that are used by the profiler runtime. Since these show up as globals in the LLVM IR, the compiler generates `dllimport`-related `__imp_` stubs for them. This can lead to linker errors because the instrumentation symbols have weak linkage or are in a comdat section, but the `__imp_` stubs aren't.
Instead of trying to replicate the linkage/comdat setup for the stubs, this PR just excludes the profiler-related symbols from stub-generation since they aren't supposed to be referenced via `__declspec(dllimport)` anywhere anyway.
r? @alexcrichton
EDIT: I considered making this more general, i.e. inferring from the symbol name if it is a Rust symbol or not. But then I figured out that that would yield false negatives for `#[no_mangle]` et al, so I went with a blacklist approach.
I was trying to output LLVM IR directly to the console:
$ rustc hello.rs --emit=llvm-ir -o /dev/stdout
LLVM ERROR: IO failure on output stream: Bad file descriptor
Now `LLVMRustPrintModule` returns an error, and we print:
error: failed to write LLVM IR to /dev/stdout.hello.7rcbfp3g-cgu.0.rcgu.ll: Permission denied
... which is more informative.
Enable -mergefunc-use-aliases
If the Rust LLVM fork is used, enable the -mergefunc-use-aliases
flag, which will create aliases for merged functions, rather than
inserting a call from one to the other.
A number of codegen tests needed to be adjusted, because functions
that previously fell below the thunk limit are now being merged.
Merging is prevented in various ways now.
I expect that this is going to break something, somewhere, because
it isn't able to deal with aliases properly, but we won't find out
until we try :)
This fixes#52651.
r? @rkruppe
name-anon-globals should always be run at the very end of the pass
pipeline, as optimization passes (in particular mergefunc) may
introduce new anonymous globals.
I believe we did not run into this earlier because it requires the
rather specific combination of a) mergefunc merging two weak functions
b) compilation not using thinlto.
