blob: 62998003ca1148825b94f537c0955487ee26267c [file] [log] [blame]
use std::ffi::{CStr, CString};
use std::io::{self, Write};
use std::path::{Path, PathBuf};
use std::ptr::null_mut;
use std::sync::Arc;
use std::{fs, slice, str};
use libc::{c_char, c_int, c_void, size_t};
use llvm::{
LLVMRustLLVMHasZlibCompressionForDebugSymbols, LLVMRustLLVMHasZstdCompressionForDebugSymbols,
};
use rustc_codegen_ssa::back::link::ensure_removed;
use rustc_codegen_ssa::back::versioned_llvm_target;
use rustc_codegen_ssa::back::write::{
BitcodeSection, CodegenContext, EmitObj, ModuleConfig, TargetMachineFactoryConfig,
TargetMachineFactoryFn,
};
use rustc_codegen_ssa::base::wants_wasm_eh;
use rustc_codegen_ssa::traits::*;
use rustc_codegen_ssa::{CompiledModule, ModuleCodegen, ModuleKind};
use rustc_data_structures::profiling::SelfProfilerRef;
use rustc_data_structures::small_c_str::SmallCStr;
use rustc_errors::{DiagCtxtHandle, FatalError, Level};
use rustc_fs_util::{link_or_copy, path_to_c_string};
use rustc_middle::ty::TyCtxt;
use rustc_session::Session;
use rustc_session::config::{
self, Lto, OutputType, Passes, RemapPathScopeComponents, SplitDwarfKind, SwitchWithOptPath,
};
use rustc_span::{BytePos, InnerSpan, Pos, SpanData, SyntaxContext, sym};
use rustc_target::spec::{CodeModel, FloatAbi, RelocModel, SanitizerSet, SplitDebuginfo, TlsModel};
use tracing::{debug, trace};
use crate::back::lto::ThinBuffer;
use crate::back::owned_target_machine::OwnedTargetMachine;
use crate::back::profiling::{
LlvmSelfProfiler, selfprofile_after_pass_callback, selfprofile_before_pass_callback,
};
use crate::common::AsCCharPtr;
use crate::errors::{
CopyBitcode, FromLlvmDiag, FromLlvmOptimizationDiag, LlvmError, UnknownCompression,
WithLlvmError, WriteBytecode,
};
use crate::llvm::diagnostic::OptimizationDiagnosticKind::*;
use crate::llvm::{self, DiagnosticInfo};
use crate::type_::Type;
use crate::{LlvmCodegenBackend, ModuleLlvm, base, common, llvm_util};
pub(crate) fn llvm_err<'a>(dcx: DiagCtxtHandle<'_>, err: LlvmError<'a>) -> FatalError {
match llvm::last_error() {
Some(llvm_err) => dcx.emit_almost_fatal(WithLlvmError(err, llvm_err)),
None => dcx.emit_almost_fatal(err),
}
}
fn write_output_file<'ll>(
dcx: DiagCtxtHandle<'_>,
target: &'ll llvm::TargetMachine,
no_builtins: bool,
m: &'ll llvm::Module,
output: &Path,
dwo_output: Option<&Path>,
file_type: llvm::FileType,
self_profiler_ref: &SelfProfilerRef,
verify_llvm_ir: bool,
) -> Result<(), FatalError> {
debug!("write_output_file output={:?} dwo_output={:?}", output, dwo_output);
let output_c = path_to_c_string(output);
let dwo_output_c;
let dwo_output_ptr = if let Some(dwo_output) = dwo_output {
dwo_output_c = path_to_c_string(dwo_output);
dwo_output_c.as_ptr()
} else {
std::ptr::null()
};
let result = unsafe {
let pm = llvm::LLVMCreatePassManager();
llvm::LLVMAddAnalysisPasses(target, pm);
llvm::LLVMRustAddLibraryInfo(pm, m, no_builtins);
llvm::LLVMRustWriteOutputFile(
target,
pm,
m,
output_c.as_ptr(),
dwo_output_ptr,
file_type,
verify_llvm_ir,
)
};
// Record artifact sizes for self-profiling
if result == llvm::LLVMRustResult::Success {
let artifact_kind = match file_type {
llvm::FileType::ObjectFile => "object_file",
llvm::FileType::AssemblyFile => "assembly_file",
};
record_artifact_size(self_profiler_ref, artifact_kind, output);
if let Some(dwo_file) = dwo_output {
record_artifact_size(self_profiler_ref, "dwo_file", dwo_file);
}
}
result.into_result().map_err(|()| llvm_err(dcx, LlvmError::WriteOutput { path: output }))
}
pub(crate) fn create_informational_target_machine(
sess: &Session,
only_base_features: bool,
) -> OwnedTargetMachine {
let config = TargetMachineFactoryConfig { split_dwarf_file: None, output_obj_file: None };
// Can't use query system here quite yet because this function is invoked before the query
// system/tcx is set up.
let features = llvm_util::global_llvm_features(sess, false, only_base_features);
target_machine_factory(sess, config::OptLevel::No, &features)(config)
.unwrap_or_else(|err| llvm_err(sess.dcx(), err).raise())
}
pub(crate) fn create_target_machine(tcx: TyCtxt<'_>, mod_name: &str) -> OwnedTargetMachine {
let split_dwarf_file = if tcx.sess.target_can_use_split_dwarf() {
tcx.output_filenames(()).split_dwarf_path(
tcx.sess.split_debuginfo(),
tcx.sess.opts.unstable_opts.split_dwarf_kind,
mod_name,
tcx.sess.invocation_temp.as_deref(),
)
} else {
None
};
let output_obj_file = Some(tcx.output_filenames(()).temp_path_for_cgu(
OutputType::Object,
mod_name,
tcx.sess.invocation_temp.as_deref(),
));
let config = TargetMachineFactoryConfig { split_dwarf_file, output_obj_file };
target_machine_factory(
tcx.sess,
tcx.backend_optimization_level(()),
tcx.global_backend_features(()),
)(config)
.unwrap_or_else(|err| llvm_err(tcx.dcx(), err).raise())
}
fn to_llvm_opt_settings(cfg: config::OptLevel) -> (llvm::CodeGenOptLevel, llvm::CodeGenOptSize) {
use self::config::OptLevel::*;
match cfg {
No => (llvm::CodeGenOptLevel::None, llvm::CodeGenOptSizeNone),
Less => (llvm::CodeGenOptLevel::Less, llvm::CodeGenOptSizeNone),
More => (llvm::CodeGenOptLevel::Default, llvm::CodeGenOptSizeNone),
Aggressive => (llvm::CodeGenOptLevel::Aggressive, llvm::CodeGenOptSizeNone),
Size => (llvm::CodeGenOptLevel::Default, llvm::CodeGenOptSizeDefault),
SizeMin => (llvm::CodeGenOptLevel::Default, llvm::CodeGenOptSizeAggressive),
}
}
fn to_pass_builder_opt_level(cfg: config::OptLevel) -> llvm::PassBuilderOptLevel {
use config::OptLevel::*;
match cfg {
No => llvm::PassBuilderOptLevel::O0,
Less => llvm::PassBuilderOptLevel::O1,
More => llvm::PassBuilderOptLevel::O2,
Aggressive => llvm::PassBuilderOptLevel::O3,
Size => llvm::PassBuilderOptLevel::Os,
SizeMin => llvm::PassBuilderOptLevel::Oz,
}
}
fn to_llvm_relocation_model(relocation_model: RelocModel) -> llvm::RelocModel {
match relocation_model {
RelocModel::Static => llvm::RelocModel::Static,
// LLVM doesn't have a PIE relocation model, it represents PIE as PIC with an extra
// attribute.
RelocModel::Pic | RelocModel::Pie => llvm::RelocModel::PIC,
RelocModel::DynamicNoPic => llvm::RelocModel::DynamicNoPic,
RelocModel::Ropi => llvm::RelocModel::ROPI,
RelocModel::Rwpi => llvm::RelocModel::RWPI,
RelocModel::RopiRwpi => llvm::RelocModel::ROPI_RWPI,
}
}
pub(crate) fn to_llvm_code_model(code_model: Option<CodeModel>) -> llvm::CodeModel {
match code_model {
Some(CodeModel::Tiny) => llvm::CodeModel::Tiny,
Some(CodeModel::Small) => llvm::CodeModel::Small,
Some(CodeModel::Kernel) => llvm::CodeModel::Kernel,
Some(CodeModel::Medium) => llvm::CodeModel::Medium,
Some(CodeModel::Large) => llvm::CodeModel::Large,
None => llvm::CodeModel::None,
}
}
fn to_llvm_float_abi(float_abi: Option<FloatAbi>) -> llvm::FloatAbi {
match float_abi {
None => llvm::FloatAbi::Default,
Some(FloatAbi::Soft) => llvm::FloatAbi::Soft,
Some(FloatAbi::Hard) => llvm::FloatAbi::Hard,
}
}
pub(crate) fn target_machine_factory(
sess: &Session,
optlvl: config::OptLevel,
target_features: &[String],
) -> TargetMachineFactoryFn<LlvmCodegenBackend> {
let reloc_model = to_llvm_relocation_model(sess.relocation_model());
let (opt_level, _) = to_llvm_opt_settings(optlvl);
let float_abi = if sess.target.arch == "arm" && sess.opts.cg.soft_float {
llvm::FloatAbi::Soft
} else {
// `validate_commandline_args_with_session_available` has already warned about this being
// ignored. Let's make sure LLVM doesn't suddenly start using this flag on more targets.
to_llvm_float_abi(sess.target.llvm_floatabi)
};
let ffunction_sections =
sess.opts.unstable_opts.function_sections.unwrap_or(sess.target.function_sections);
let fdata_sections = ffunction_sections;
let funique_section_names = !sess.opts.unstable_opts.no_unique_section_names;
let code_model = to_llvm_code_model(sess.code_model());
let mut singlethread = sess.target.singlethread;
// On the wasm target once the `atomics` feature is enabled that means that
// we're no longer single-threaded, or otherwise we don't want LLVM to
// lower atomic operations to single-threaded operations.
if singlethread && sess.target.is_like_wasm && sess.target_features.contains(&sym::atomics) {
singlethread = false;
}
let triple = SmallCStr::new(&versioned_llvm_target(sess));
let cpu = SmallCStr::new(llvm_util::target_cpu(sess));
let features = CString::new(target_features.join(",")).unwrap();
let abi = SmallCStr::new(&sess.target.llvm_abiname);
let trap_unreachable =
sess.opts.unstable_opts.trap_unreachable.unwrap_or(sess.target.trap_unreachable);
let emit_stack_size_section = sess.opts.unstable_opts.emit_stack_sizes;
let verbose_asm = sess.opts.unstable_opts.verbose_asm;
let relax_elf_relocations =
sess.opts.unstable_opts.relax_elf_relocations.unwrap_or(sess.target.relax_elf_relocations);
let use_init_array =
!sess.opts.unstable_opts.use_ctors_section.unwrap_or(sess.target.use_ctors_section);
let path_mapping = sess.source_map().path_mapping().clone();
let use_emulated_tls = matches!(sess.tls_model(), TlsModel::Emulated);
// copy the exe path, followed by path all into one buffer
// null terminating them so we can use them as null terminated strings
let args_cstr_buff = {
let mut args_cstr_buff: Vec<u8> = Vec::new();
let exe_path = std::env::current_exe().unwrap_or_default();
let exe_path_str = exe_path.into_os_string().into_string().unwrap_or_default();
args_cstr_buff.extend_from_slice(exe_path_str.as_bytes());
args_cstr_buff.push(0);
for arg in sess.expanded_args.iter() {
args_cstr_buff.extend_from_slice(arg.as_bytes());
args_cstr_buff.push(0);
}
args_cstr_buff
};
let debuginfo_compression = sess.opts.debuginfo_compression.to_string();
match sess.opts.debuginfo_compression {
rustc_session::config::DebugInfoCompression::Zlib => {
if !unsafe { LLVMRustLLVMHasZlibCompressionForDebugSymbols() } {
sess.dcx().emit_warn(UnknownCompression { algorithm: "zlib" });
}
}
rustc_session::config::DebugInfoCompression::Zstd => {
if !unsafe { LLVMRustLLVMHasZstdCompressionForDebugSymbols() } {
sess.dcx().emit_warn(UnknownCompression { algorithm: "zstd" });
}
}
rustc_session::config::DebugInfoCompression::None => {}
};
let debuginfo_compression = SmallCStr::new(&debuginfo_compression);
let file_name_display_preference =
sess.filename_display_preference(RemapPathScopeComponents::DEBUGINFO);
let use_wasm_eh = wants_wasm_eh(sess);
Arc::new(move |config: TargetMachineFactoryConfig| {
let path_to_cstring_helper = |path: Option<PathBuf>| -> CString {
let path = path.unwrap_or_default();
let path = path_mapping
.to_real_filename(path)
.to_string_lossy(file_name_display_preference)
.into_owned();
CString::new(path).unwrap()
};
let split_dwarf_file = path_to_cstring_helper(config.split_dwarf_file);
let output_obj_file = path_to_cstring_helper(config.output_obj_file);
OwnedTargetMachine::new(
&triple,
&cpu,
&features,
&abi,
code_model,
reloc_model,
opt_level,
float_abi,
ffunction_sections,
fdata_sections,
funique_section_names,
trap_unreachable,
singlethread,
verbose_asm,
emit_stack_size_section,
relax_elf_relocations,
use_init_array,
&split_dwarf_file,
&output_obj_file,
&debuginfo_compression,
use_emulated_tls,
&args_cstr_buff,
use_wasm_eh,
)
})
}
pub(crate) fn save_temp_bitcode(
cgcx: &CodegenContext<LlvmCodegenBackend>,
module: &ModuleCodegen<ModuleLlvm>,
name: &str,
) {
if !cgcx.save_temps {
return;
}
let ext = format!("{name}.bc");
let path = cgcx.output_filenames.temp_path_ext_for_cgu(
&ext,
&module.name,
cgcx.invocation_temp.as_deref(),
);
write_bitcode_to_file(module, &path)
}
fn write_bitcode_to_file(module: &ModuleCodegen<ModuleLlvm>, path: &Path) {
unsafe {
let path = path_to_c_string(&path);
let llmod = module.module_llvm.llmod();
llvm::LLVMWriteBitcodeToFile(llmod, path.as_ptr());
}
}
/// In what context is a dignostic handler being attached to a codegen unit?
pub(crate) enum CodegenDiagnosticsStage {
/// Prelink optimization stage.
Opt,
/// LTO/ThinLTO postlink optimization stage.
LTO,
/// Code generation.
Codegen,
}
pub(crate) struct DiagnosticHandlers<'a> {
data: *mut (&'a CodegenContext<LlvmCodegenBackend>, DiagCtxtHandle<'a>),
llcx: &'a llvm::Context,
old_handler: Option<&'a llvm::DiagnosticHandler>,
}
impl<'a> DiagnosticHandlers<'a> {
pub(crate) fn new(
cgcx: &'a CodegenContext<LlvmCodegenBackend>,
dcx: DiagCtxtHandle<'a>,
llcx: &'a llvm::Context,
module: &ModuleCodegen<ModuleLlvm>,
stage: CodegenDiagnosticsStage,
) -> Self {
let remark_passes_all: bool;
let remark_passes: Vec<CString>;
match &cgcx.remark {
Passes::All => {
remark_passes_all = true;
remark_passes = Vec::new();
}
Passes::Some(passes) => {
remark_passes_all = false;
remark_passes =
passes.iter().map(|name| CString::new(name.as_str()).unwrap()).collect();
}
};
let remark_passes: Vec<*const c_char> =
remark_passes.iter().map(|name: &CString| name.as_ptr()).collect();
let remark_file = cgcx
.remark_dir
.as_ref()
// Use the .opt.yaml file suffix, which is supported by LLVM's opt-viewer.
.map(|dir| {
let stage_suffix = match stage {
CodegenDiagnosticsStage::Codegen => "codegen",
CodegenDiagnosticsStage::Opt => "opt",
CodegenDiagnosticsStage::LTO => "lto",
};
dir.join(format!("{}.{stage_suffix}.opt.yaml", module.name))
})
.and_then(|dir| dir.to_str().and_then(|p| CString::new(p).ok()));
let pgo_available = cgcx.opts.cg.profile_use.is_some();
let data = Box::into_raw(Box::new((cgcx, dcx)));
unsafe {
let old_handler = llvm::LLVMRustContextGetDiagnosticHandler(llcx);
llvm::LLVMRustContextConfigureDiagnosticHandler(
llcx,
diagnostic_handler,
data.cast(),
remark_passes_all,
remark_passes.as_ptr(),
remark_passes.len(),
// The `as_ref()` is important here, otherwise the `CString` will be dropped
// too soon!
remark_file.as_ref().map(|dir| dir.as_ptr()).unwrap_or(std::ptr::null()),
pgo_available,
);
DiagnosticHandlers { data, llcx, old_handler }
}
}
}
impl<'a> Drop for DiagnosticHandlers<'a> {
fn drop(&mut self) {
unsafe {
llvm::LLVMRustContextSetDiagnosticHandler(self.llcx, self.old_handler);
drop(Box::from_raw(self.data));
}
}
}
fn report_inline_asm(
cgcx: &CodegenContext<LlvmCodegenBackend>,
msg: String,
level: llvm::DiagnosticLevel,
cookie: u64,
source: Option<(String, Vec<InnerSpan>)>,
) {
// In LTO build we may get srcloc values from other crates which are invalid
// since they use a different source map. To be safe we just suppress these
// in LTO builds.
let span = if cookie == 0 || matches!(cgcx.lto, Lto::Fat | Lto::Thin) {
SpanData::default()
} else {
SpanData {
lo: BytePos::from_u32(cookie as u32),
hi: BytePos::from_u32((cookie >> 32) as u32),
ctxt: SyntaxContext::root(),
parent: None,
}
};
let level = match level {
llvm::DiagnosticLevel::Error => Level::Error,
llvm::DiagnosticLevel::Warning => Level::Warning,
llvm::DiagnosticLevel::Note | llvm::DiagnosticLevel::Remark => Level::Note,
};
let msg = msg.strip_prefix("error: ").unwrap_or(&msg).to_string();
cgcx.diag_emitter.inline_asm_error(span, msg, level, source);
}
unsafe extern "C" fn diagnostic_handler(info: &DiagnosticInfo, user: *mut c_void) {
if user.is_null() {
return;
}
let (cgcx, dcx) =
unsafe { *(user as *const (&CodegenContext<LlvmCodegenBackend>, DiagCtxtHandle<'_>)) };
match unsafe { llvm::diagnostic::Diagnostic::unpack(info) } {
llvm::diagnostic::InlineAsm(inline) => {
report_inline_asm(cgcx, inline.message, inline.level, inline.cookie, inline.source);
}
llvm::diagnostic::Optimization(opt) => {
dcx.emit_note(FromLlvmOptimizationDiag {
filename: &opt.filename,
line: opt.line,
column: opt.column,
pass_name: &opt.pass_name,
kind: match opt.kind {
OptimizationRemark => "success",
OptimizationMissed | OptimizationFailure => "missed",
OptimizationAnalysis
| OptimizationAnalysisFPCommute
| OptimizationAnalysisAliasing => "analysis",
OptimizationRemarkOther => "other",
},
message: &opt.message,
});
}
llvm::diagnostic::PGO(diagnostic_ref) | llvm::diagnostic::Linker(diagnostic_ref) => {
let message = llvm::build_string(|s| unsafe {
llvm::LLVMRustWriteDiagnosticInfoToString(diagnostic_ref, s)
})
.expect("non-UTF8 diagnostic");
dcx.emit_warn(FromLlvmDiag { message });
}
llvm::diagnostic::Unsupported(diagnostic_ref) => {
let message = llvm::build_string(|s| unsafe {
llvm::LLVMRustWriteDiagnosticInfoToString(diagnostic_ref, s)
})
.expect("non-UTF8 diagnostic");
dcx.emit_err(FromLlvmDiag { message });
}
llvm::diagnostic::UnknownDiagnostic(..) => {}
}
}
fn get_pgo_gen_path(config: &ModuleConfig) -> Option<CString> {
match config.pgo_gen {
SwitchWithOptPath::Enabled(ref opt_dir_path) => {
let path = if let Some(dir_path) = opt_dir_path {
dir_path.join("default_%m.profraw")
} else {
PathBuf::from("default_%m.profraw")
};
Some(CString::new(format!("{}", path.display())).unwrap())
}
SwitchWithOptPath::Disabled => None,
}
}
fn get_pgo_use_path(config: &ModuleConfig) -> Option<CString> {
config
.pgo_use
.as_ref()
.map(|path_buf| CString::new(path_buf.to_string_lossy().as_bytes()).unwrap())
}
fn get_pgo_sample_use_path(config: &ModuleConfig) -> Option<CString> {
config
.pgo_sample_use
.as_ref()
.map(|path_buf| CString::new(path_buf.to_string_lossy().as_bytes()).unwrap())
}
fn get_instr_profile_output_path(config: &ModuleConfig) -> Option<CString> {
config.instrument_coverage.then(|| c"default_%m_%p.profraw".to_owned())
}
// PreAD will run llvm opts but disable size increasing opts (vectorization, loop unrolling)
// DuringAD is the same as above, but also runs the enzyme opt and autodiff passes.
// PostAD will run all opts, including size increasing opts.
#[derive(Debug, Eq, PartialEq)]
pub(crate) enum AutodiffStage {
PreAD,
DuringAD,
PostAD,
}
pub(crate) unsafe fn llvm_optimize(
cgcx: &CodegenContext<LlvmCodegenBackend>,
dcx: DiagCtxtHandle<'_>,
module: &ModuleCodegen<ModuleLlvm>,
thin_lto_buffer: Option<&mut *mut llvm::ThinLTOBuffer>,
config: &ModuleConfig,
opt_level: config::OptLevel,
opt_stage: llvm::OptStage,
autodiff_stage: AutodiffStage,
) -> Result<(), FatalError> {
// Enzyme:
// The whole point of compiler based AD is to differentiate optimized IR instead of unoptimized
// source code. However, benchmarks show that optimizations increasing the code size
// tend to reduce AD performance. Therefore deactivate them before AD, then differentiate the code
// and finally re-optimize the module, now with all optimizations available.
// FIXME(ZuseZ4): In a future update we could figure out how to only optimize individual functions getting
// differentiated.
let consider_ad = cfg!(llvm_enzyme) && config.autodiff.contains(&config::AutoDiff::Enable);
let run_enzyme = autodiff_stage == AutodiffStage::DuringAD;
let print_before_enzyme = config.autodiff.contains(&config::AutoDiff::PrintModBefore);
let print_after_enzyme = config.autodiff.contains(&config::AutoDiff::PrintModAfter);
let print_passes = config.autodiff.contains(&config::AutoDiff::PrintPasses);
let merge_functions;
let unroll_loops;
let vectorize_slp;
let vectorize_loop;
// When we build rustc with enzyme/autodiff support, we want to postpone size-increasing
// optimizations until after differentiation. Our pipeline is thus: (opt + enzyme), (full opt).
// We therefore have two calls to llvm_optimize, if autodiff is used.
//
// We also must disable merge_functions, since autodiff placeholder/dummy bodies tend to be
// identical. We run opts before AD, so there is a chance that LLVM will merge our dummies.
// In that case, we lack some dummy bodies and can't replace them with the real AD code anymore.
// We then would need to abort compilation. This was especially common in test cases.
if consider_ad && autodiff_stage != AutodiffStage::PostAD {
merge_functions = false;
unroll_loops = false;
vectorize_slp = false;
vectorize_loop = false;
} else {
unroll_loops =
opt_level != config::OptLevel::Size && opt_level != config::OptLevel::SizeMin;
merge_functions = config.merge_functions;
vectorize_slp = config.vectorize_slp;
vectorize_loop = config.vectorize_loop;
}
trace!(?unroll_loops, ?vectorize_slp, ?vectorize_loop, ?run_enzyme);
if thin_lto_buffer.is_some() {
assert!(
matches!(
opt_stage,
llvm::OptStage::PreLinkNoLTO
| llvm::OptStage::PreLinkFatLTO
| llvm::OptStage::PreLinkThinLTO
),
"the bitcode for LTO can only be obtained at the pre-link stage"
);
}
let pgo_gen_path = get_pgo_gen_path(config);
let pgo_use_path = get_pgo_use_path(config);
let pgo_sample_use_path = get_pgo_sample_use_path(config);
let is_lto = opt_stage == llvm::OptStage::ThinLTO || opt_stage == llvm::OptStage::FatLTO;
let instr_profile_output_path = get_instr_profile_output_path(config);
let sanitize_dataflow_abilist: Vec<_> = config
.sanitizer_dataflow_abilist
.iter()
.map(|file| CString::new(file.as_str()).unwrap())
.collect();
let sanitize_dataflow_abilist_ptrs: Vec<_> =
sanitize_dataflow_abilist.iter().map(|file| file.as_ptr()).collect();
// Sanitizer instrumentation is only inserted during the pre-link optimization stage.
let sanitizer_options = if !is_lto {
Some(llvm::SanitizerOptions {
sanitize_address: config.sanitizer.contains(SanitizerSet::ADDRESS),
sanitize_address_recover: config.sanitizer_recover.contains(SanitizerSet::ADDRESS),
sanitize_cfi: config.sanitizer.contains(SanitizerSet::CFI),
sanitize_dataflow: config.sanitizer.contains(SanitizerSet::DATAFLOW),
sanitize_dataflow_abilist: sanitize_dataflow_abilist_ptrs.as_ptr(),
sanitize_dataflow_abilist_len: sanitize_dataflow_abilist_ptrs.len(),
sanitize_kcfi: config.sanitizer.contains(SanitizerSet::KCFI),
sanitize_memory: config.sanitizer.contains(SanitizerSet::MEMORY),
sanitize_memory_recover: config.sanitizer_recover.contains(SanitizerSet::MEMORY),
sanitize_memory_track_origins: config.sanitizer_memory_track_origins as c_int,
sanitize_thread: config.sanitizer.contains(SanitizerSet::THREAD),
sanitize_hwaddress: config.sanitizer.contains(SanitizerSet::HWADDRESS),
sanitize_hwaddress_recover: config.sanitizer_recover.contains(SanitizerSet::HWADDRESS),
sanitize_kernel_address: config.sanitizer.contains(SanitizerSet::KERNELADDRESS),
sanitize_kernel_address_recover: config
.sanitizer_recover
.contains(SanitizerSet::KERNELADDRESS),
})
} else {
None
};
let mut llvm_profiler = cgcx
.prof
.llvm_recording_enabled()
.then(|| LlvmSelfProfiler::new(cgcx.prof.get_self_profiler().unwrap()));
let llvm_selfprofiler =
llvm_profiler.as_mut().map(|s| s as *mut _ as *mut c_void).unwrap_or(std::ptr::null_mut());
let extra_passes = if !is_lto { config.passes.join(",") } else { "".to_string() };
let llvm_plugins = config.llvm_plugins.join(",");
let result = unsafe {
llvm::LLVMRustOptimize(
module.module_llvm.llmod(),
&*module.module_llvm.tm.raw(),
to_pass_builder_opt_level(opt_level),
opt_stage,
cgcx.opts.cg.linker_plugin_lto.enabled(),
config.no_prepopulate_passes,
config.verify_llvm_ir,
config.lint_llvm_ir,
thin_lto_buffer,
config.emit_thin_lto,
config.emit_thin_lto_summary,
merge_functions,
unroll_loops,
vectorize_slp,
vectorize_loop,
config.no_builtins,
config.emit_lifetime_markers,
run_enzyme,
print_before_enzyme,
print_after_enzyme,
print_passes,
sanitizer_options.as_ref(),
pgo_gen_path.as_ref().map_or(std::ptr::null(), |s| s.as_ptr()),
pgo_use_path.as_ref().map_or(std::ptr::null(), |s| s.as_ptr()),
config.instrument_coverage,
instr_profile_output_path.as_ref().map_or(std::ptr::null(), |s| s.as_ptr()),
pgo_sample_use_path.as_ref().map_or(std::ptr::null(), |s| s.as_ptr()),
config.debug_info_for_profiling,
llvm_selfprofiler,
selfprofile_before_pass_callback,
selfprofile_after_pass_callback,
extra_passes.as_c_char_ptr(),
extra_passes.len(),
llvm_plugins.as_c_char_ptr(),
llvm_plugins.len(),
)
};
result.into_result().map_err(|()| llvm_err(dcx, LlvmError::RunLlvmPasses))
}
// Unsafe due to LLVM calls.
pub(crate) fn optimize(
cgcx: &CodegenContext<LlvmCodegenBackend>,
dcx: DiagCtxtHandle<'_>,
module: &mut ModuleCodegen<ModuleLlvm>,
config: &ModuleConfig,
) -> Result<(), FatalError> {
let _timer = cgcx.prof.generic_activity_with_arg("LLVM_module_optimize", &*module.name);
let llcx = &*module.module_llvm.llcx;
let _handlers = DiagnosticHandlers::new(cgcx, dcx, llcx, module, CodegenDiagnosticsStage::Opt);
if config.emit_no_opt_bc {
let out = cgcx.output_filenames.temp_path_ext_for_cgu(
"no-opt.bc",
&module.name,
cgcx.invocation_temp.as_deref(),
);
write_bitcode_to_file(module, &out)
}
// FIXME(ZuseZ4): support SanitizeHWAddress and prevent illegal/unsupported opts
if let Some(opt_level) = config.opt_level {
let opt_stage = match cgcx.lto {
Lto::Fat => llvm::OptStage::PreLinkFatLTO,
Lto::Thin | Lto::ThinLocal => llvm::OptStage::PreLinkThinLTO,
_ if cgcx.opts.cg.linker_plugin_lto.enabled() => llvm::OptStage::PreLinkThinLTO,
_ => llvm::OptStage::PreLinkNoLTO,
};
// If we know that we will later run AD, then we disable vectorization and loop unrolling.
// Otherwise we pretend AD is already done and run the normal opt pipeline (=PostAD).
let consider_ad = cfg!(llvm_enzyme) && config.autodiff.contains(&config::AutoDiff::Enable);
let autodiff_stage = if consider_ad { AutodiffStage::PreAD } else { AutodiffStage::PostAD };
// The embedded bitcode is used to run LTO/ThinLTO.
// The bitcode obtained during the `codegen` phase is no longer suitable for performing LTO.
// It may have undergone LTO due to ThinLocal, so we need to obtain the embedded bitcode at
// this point.
let mut thin_lto_buffer = if (module.kind == ModuleKind::Regular
&& config.emit_obj == EmitObj::ObjectCode(BitcodeSection::Full))
|| config.emit_thin_lto_summary
{
Some(null_mut())
} else {
None
};
unsafe {
llvm_optimize(
cgcx,
dcx,
module,
thin_lto_buffer.as_mut(),
config,
opt_level,
opt_stage,
autodiff_stage,
)
}?;
if let Some(thin_lto_buffer) = thin_lto_buffer {
let thin_lto_buffer = unsafe { ThinBuffer::from_raw_ptr(thin_lto_buffer) };
module.thin_lto_buffer = Some(thin_lto_buffer.data().to_vec());
let bc_summary_out = cgcx.output_filenames.temp_path_for_cgu(
OutputType::ThinLinkBitcode,
&module.name,
cgcx.invocation_temp.as_deref(),
);
if config.emit_thin_lto_summary
&& let Some(thin_link_bitcode_filename) = bc_summary_out.file_name()
{
let summary_data = thin_lto_buffer.thin_link_data();
cgcx.prof.artifact_size(
"llvm_bitcode_summary",
thin_link_bitcode_filename.to_string_lossy(),
summary_data.len() as u64,
);
let _timer = cgcx.prof.generic_activity_with_arg(
"LLVM_module_codegen_emit_bitcode_summary",
&*module.name,
);
if let Err(err) = fs::write(&bc_summary_out, summary_data) {
dcx.emit_err(WriteBytecode { path: &bc_summary_out, err });
}
}
}
}
Ok(())
}
pub(crate) fn codegen(
cgcx: &CodegenContext<LlvmCodegenBackend>,
module: ModuleCodegen<ModuleLlvm>,
config: &ModuleConfig,
) -> Result<CompiledModule, FatalError> {
let dcx = cgcx.create_dcx();
let dcx = dcx.handle();
let _timer = cgcx.prof.generic_activity_with_arg("LLVM_module_codegen", &*module.name);
{
let llmod = module.module_llvm.llmod();
let llcx = &*module.module_llvm.llcx;
let tm = &*module.module_llvm.tm;
let _handlers =
DiagnosticHandlers::new(cgcx, dcx, llcx, &module, CodegenDiagnosticsStage::Codegen);
if cgcx.msvc_imps_needed {
create_msvc_imps(cgcx, llcx, llmod);
}
// Note that if object files are just LLVM bitcode we write bitcode,
// copy it to the .o file, and delete the bitcode if it wasn't
// otherwise requested.
let bc_out = cgcx.output_filenames.temp_path_for_cgu(
OutputType::Bitcode,
&module.name,
cgcx.invocation_temp.as_deref(),
);
let obj_out = cgcx.output_filenames.temp_path_for_cgu(
OutputType::Object,
&module.name,
cgcx.invocation_temp.as_deref(),
);
if config.bitcode_needed() {
if config.emit_bc || config.emit_obj == EmitObj::Bitcode {
let thin = {
let _timer = cgcx.prof.generic_activity_with_arg(
"LLVM_module_codegen_make_bitcode",
&*module.name,
);
ThinBuffer::new(llmod, config.emit_thin_lto, false)
};
let data = thin.data();
let _timer = cgcx
.prof
.generic_activity_with_arg("LLVM_module_codegen_emit_bitcode", &*module.name);
if let Some(bitcode_filename) = bc_out.file_name() {
cgcx.prof.artifact_size(
"llvm_bitcode",
bitcode_filename.to_string_lossy(),
data.len() as u64,
);
}
if let Err(err) = fs::write(&bc_out, data) {
dcx.emit_err(WriteBytecode { path: &bc_out, err });
}
}
if config.embed_bitcode() && module.kind == ModuleKind::Regular {
let _timer = cgcx
.prof
.generic_activity_with_arg("LLVM_module_codegen_embed_bitcode", &*module.name);
let thin_bc =
module.thin_lto_buffer.as_deref().expect("cannot find embedded bitcode");
embed_bitcode(cgcx, llcx, llmod, &thin_bc);
}
}
if config.emit_ir {
let _timer =
cgcx.prof.generic_activity_with_arg("LLVM_module_codegen_emit_ir", &*module.name);
let out = cgcx.output_filenames.temp_path_for_cgu(
OutputType::LlvmAssembly,
&module.name,
cgcx.invocation_temp.as_deref(),
);
let out_c = path_to_c_string(&out);
extern "C" fn demangle_callback(
input_ptr: *const c_char,
input_len: size_t,
output_ptr: *mut c_char,
output_len: size_t,
) -> size_t {
let input =
unsafe { slice::from_raw_parts(input_ptr as *const u8, input_len as usize) };
let Ok(input) = str::from_utf8(input) else { return 0 };
let output = unsafe {
slice::from_raw_parts_mut(output_ptr as *mut u8, output_len as usize)
};
let mut cursor = io::Cursor::new(output);
let Ok(demangled) = rustc_demangle::try_demangle(input) else { return 0 };
if write!(cursor, "{demangled:#}").is_err() {
// Possible only if provided buffer is not big enough
return 0;
}
cursor.position() as size_t
}
let result =
unsafe { llvm::LLVMRustPrintModule(llmod, out_c.as_ptr(), demangle_callback) };
if result == llvm::LLVMRustResult::Success {
record_artifact_size(&cgcx.prof, "llvm_ir", &out);
}
result.into_result().map_err(|()| llvm_err(dcx, LlvmError::WriteIr { path: &out }))?;
}
if config.emit_asm {
let _timer =
cgcx.prof.generic_activity_with_arg("LLVM_module_codegen_emit_asm", &*module.name);
let path = cgcx.output_filenames.temp_path_for_cgu(
OutputType::Assembly,
&module.name,
cgcx.invocation_temp.as_deref(),
);
// We can't use the same module for asm and object code output,
// because that triggers various errors like invalid IR or broken
// binaries. So we must clone the module to produce the asm output
// if we are also producing object code.
let llmod = if let EmitObj::ObjectCode(_) = config.emit_obj {
llvm::LLVMCloneModule(llmod)
} else {
llmod
};
write_output_file(
dcx,
tm.raw(),
config.no_builtins,
llmod,
&path,
None,
llvm::FileType::AssemblyFile,
&cgcx.prof,
config.verify_llvm_ir,
)?;
}
match config.emit_obj {
EmitObj::ObjectCode(_) => {
let _timer = cgcx
.prof
.generic_activity_with_arg("LLVM_module_codegen_emit_obj", &*module.name);
let dwo_out = cgcx
.output_filenames
.temp_path_dwo_for_cgu(&module.name, cgcx.invocation_temp.as_deref());
let dwo_out = match (cgcx.split_debuginfo, cgcx.split_dwarf_kind) {
// Don't change how DWARF is emitted when disabled.
(SplitDebuginfo::Off, _) => None,
// Don't provide a DWARF object path if split debuginfo is enabled but this is
// a platform that doesn't support Split DWARF.
_ if !cgcx.target_can_use_split_dwarf => None,
// Don't provide a DWARF object path in single mode, sections will be written
// into the object as normal but ignored by linker.
(_, SplitDwarfKind::Single) => None,
// Emit (a subset of the) DWARF into a separate dwarf object file in split
// mode.
(_, SplitDwarfKind::Split) => Some(dwo_out.as_path()),
};
write_output_file(
dcx,
tm.raw(),
config.no_builtins,
llmod,
&obj_out,
dwo_out,
llvm::FileType::ObjectFile,
&cgcx.prof,
config.verify_llvm_ir,
)?;
}
EmitObj::Bitcode => {
debug!("copying bitcode {:?} to obj {:?}", bc_out, obj_out);
if let Err(err) = link_or_copy(&bc_out, &obj_out) {
dcx.emit_err(CopyBitcode { err });
}
if !config.emit_bc {
debug!("removing_bitcode {:?}", bc_out);
ensure_removed(dcx, &bc_out);
}
}
EmitObj::None => {}
}
record_llvm_cgu_instructions_stats(&cgcx.prof, llmod);
}
// `.dwo` files are only emitted if:
//
// - Object files are being emitted (i.e. bitcode only or metadata only compilations will not
// produce dwarf objects, even if otherwise enabled)
// - Target supports Split DWARF
// - Split debuginfo is enabled
// - Split DWARF kind is `split` (i.e. debuginfo is split into `.dwo` files, not different
// sections in the `.o` files).
let dwarf_object_emitted = matches!(config.emit_obj, EmitObj::ObjectCode(_))
&& cgcx.target_can_use_split_dwarf
&& cgcx.split_debuginfo != SplitDebuginfo::Off
&& cgcx.split_dwarf_kind == SplitDwarfKind::Split;
Ok(module.into_compiled_module(
config.emit_obj != EmitObj::None,
dwarf_object_emitted,
config.emit_bc,
config.emit_asm,
config.emit_ir,
&cgcx.output_filenames,
cgcx.invocation_temp.as_deref(),
))
}
fn create_section_with_flags_asm(section_name: &str, section_flags: &str, data: &[u8]) -> Vec<u8> {
let mut asm = format!(".section {section_name},\"{section_flags}\"\n").into_bytes();
asm.extend_from_slice(b".ascii \"");
asm.reserve(data.len());
for &byte in data {
if byte == b'\\' || byte == b'"' {
asm.push(b'\\');
asm.push(byte);
} else if byte < 0x20 || byte >= 0x80 {
// Avoid non UTF-8 inline assembly. Use octal escape sequence, because it is fixed
// width, while hex escapes will consume following characters.
asm.push(b'\\');
asm.push(b'0' + ((byte >> 6) & 0x7));
asm.push(b'0' + ((byte >> 3) & 0x7));
asm.push(b'0' + ((byte >> 0) & 0x7));
} else {
asm.push(byte);
}
}
asm.extend_from_slice(b"\"\n");
asm
}
pub(crate) fn bitcode_section_name(cgcx: &CodegenContext<LlvmCodegenBackend>) -> &'static CStr {
if cgcx.target_is_like_darwin {
c"__LLVM,__bitcode"
} else if cgcx.target_is_like_aix {
c".ipa"
} else {
c".llvmbc"
}
}
/// Embed the bitcode of an LLVM module for LTO in the LLVM module itself.
fn embed_bitcode(
cgcx: &CodegenContext<LlvmCodegenBackend>,
llcx: &llvm::Context,
llmod: &llvm::Module,
bitcode: &[u8],
) {
// We're adding custom sections to the output object file, but we definitely
// do not want these custom sections to make their way into the final linked
// executable. The purpose of these custom sections is for tooling
// surrounding object files to work with the LLVM IR, if necessary. For
// example rustc's own LTO will look for LLVM IR inside of the object file
// in these sections by default.
//
// To handle this is a bit different depending on the object file format
// used by the backend, broken down into a few different categories:
//
// * Mach-O - this is for macOS. Inspecting the source code for the native
// linker here shows that the `.llvmbc` and `.llvmcmd` sections are
// automatically skipped by the linker. In that case there's nothing extra
// that we need to do here. We do need to make sure that the
// `__LLVM,__cmdline` section exists even though it is empty as otherwise
// ld64 rejects the object file.
//
// * Wasm - the native LLD linker is hard-coded to skip `.llvmbc` and
// `.llvmcmd` sections, so there's nothing extra we need to do.
//
// * COFF - if we don't do anything the linker will by default copy all
// these sections to the output artifact, not what we want! To subvert
// this we want to flag the sections we inserted here as
// `IMAGE_SCN_LNK_REMOVE`.
//
// * ELF - this is very similar to COFF above. One difference is that these
// sections are removed from the output linked artifact when
// `--gc-sections` is passed, which we pass by default. If that flag isn't
// passed though then these sections will show up in the final output.
// Additionally the flag that we need to set here is `SHF_EXCLUDE`.
//
// * XCOFF - AIX linker ignores content in .ipa and .info if no auxiliary
// symbol associated with these sections.
//
// Unfortunately, LLVM provides no way to set custom section flags. For ELF
// and COFF we emit the sections using module level inline assembly for that
// reason (see issue #90326 for historical background).
if cgcx.target_is_like_darwin
|| cgcx.target_is_like_aix
|| cgcx.target_arch == "wasm32"
|| cgcx.target_arch == "wasm64"
{
// We don't need custom section flags, create LLVM globals.
let llconst = common::bytes_in_context(llcx, bitcode);
let llglobal = llvm::add_global(llmod, common::val_ty(llconst), c"rustc.embedded.module");
llvm::set_initializer(llglobal, llconst);
llvm::set_section(llglobal, bitcode_section_name(cgcx));
llvm::set_linkage(llglobal, llvm::Linkage::PrivateLinkage);
llvm::LLVMSetGlobalConstant(llglobal, llvm::True);
let llconst = common::bytes_in_context(llcx, &[]);
let llglobal = llvm::add_global(llmod, common::val_ty(llconst), c"rustc.embedded.cmdline");
llvm::set_initializer(llglobal, llconst);
let section = if cgcx.target_is_like_darwin {
c"__LLVM,__cmdline"
} else if cgcx.target_is_like_aix {
c".info"
} else {
c".llvmcmd"
};
llvm::set_section(llglobal, section);
llvm::set_linkage(llglobal, llvm::Linkage::PrivateLinkage);
} else {
// We need custom section flags, so emit module-level inline assembly.
let section_flags = if cgcx.is_pe_coff { "n" } else { "e" };
let asm = create_section_with_flags_asm(".llvmbc", section_flags, bitcode);
llvm::append_module_inline_asm(llmod, &asm);
let asm = create_section_with_flags_asm(".llvmcmd", section_flags, &[]);
llvm::append_module_inline_asm(llmod, &asm);
}
}
// Create a `__imp_<symbol> = &symbol` global for every public static `symbol`.
// This is required to satisfy `dllimport` references to static data in .rlibs
// when using MSVC linker. We do this only for data, as linker can fix up
// code references on its own.
// See #26591, #27438
fn create_msvc_imps(
cgcx: &CodegenContext<LlvmCodegenBackend>,
llcx: &llvm::Context,
llmod: &llvm::Module,
) {
if !cgcx.msvc_imps_needed {
return;
}
// The x86 ABI seems to require that leading underscores are added to symbol
// names, so we need an extra underscore on x86. There's also a leading
// '\x01' here which disables LLVM's symbol mangling (e.g., no extra
// underscores added in front).
let prefix = if cgcx.target_arch == "x86" { "\x01__imp__" } else { "\x01__imp_" };
let ptr_ty = Type::ptr_llcx(llcx);
let globals = base::iter_globals(llmod)
.filter(|&val| {
llvm::get_linkage(val) == llvm::Linkage::ExternalLinkage && !llvm::is_declaration(val)
})
.filter_map(|val| {
// Exclude some symbols that we know are not Rust symbols.
let name = llvm::get_value_name(val);
if ignored(&name) { None } else { Some((val, name)) }
})
.map(move |(val, name)| {
let mut imp_name = prefix.as_bytes().to_vec();
imp_name.extend(name);
let imp_name = CString::new(imp_name).unwrap();
(imp_name, val)
})
.collect::<Vec<_>>();
for (imp_name, val) in globals {
let imp = llvm::add_global(llmod, ptr_ty, &imp_name);
llvm::set_initializer(imp, val);
llvm::set_linkage(imp, llvm::Linkage::ExternalLinkage);
}
// Use this function to exclude certain symbols from `__imp` generation.
fn ignored(symbol_name: &[u8]) -> bool {
// These are symbols generated by LLVM's profiling instrumentation
symbol_name.starts_with(b"__llvm_profile_")
}
}
fn record_artifact_size(
self_profiler_ref: &SelfProfilerRef,
artifact_kind: &'static str,
path: &Path,
) {
// Don't stat the file if we are not going to record its size.
if !self_profiler_ref.enabled() {
return;
}
if let Some(artifact_name) = path.file_name() {
let file_size = std::fs::metadata(path).map(|m| m.len()).unwrap_or(0);
self_profiler_ref.artifact_size(artifact_kind, artifact_name.to_string_lossy(), file_size);
}
}
fn record_llvm_cgu_instructions_stats(prof: &SelfProfilerRef, llmod: &llvm::Module) {
if !prof.enabled() {
return;
}
let raw_stats =
llvm::build_string(|s| unsafe { llvm::LLVMRustModuleInstructionStats(llmod, s) })
.expect("cannot get module instruction stats");
#[derive(serde::Deserialize)]
struct InstructionsStats {
module: String,
total: u64,
}
let InstructionsStats { module, total } =
serde_json::from_str(&raw_stats).expect("cannot parse llvm cgu instructions stats");
prof.artifact_size("cgu_instructions", module, total);
}