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Allow -C debuginfo=2, but require -Zinline-mir=off, for panic! format_args! removal.

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Eduard-Mihai Burtescu 2023-07-20 04:28:10 +03:00 committed by Eduard-Mihai Burtescu
parent 4c6cf0d737
commit a0347e28c0
5 changed files with 250 additions and 108 deletions
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294
crates/rustc_codegen_spirv/src/builder/builder_methods.rs
View File

@ -4,6 +4,7 @@ use crate::builder_spirv::{BuilderCursor, SpirvConst, SpirvValue, SpirvValueExt,
use crate::custom_insts::{CustomInst, CustomOp};
use crate::rustc_codegen_ssa::traits::BaseTypeMethods;
use crate::spirv_type::SpirvType;
use itertools::Itertools;
use rspirv::dr::{InsertPoint, Instruction, Operand};
use rspirv::spirv::{Capability, MemoryModel, MemorySemantics, Op, Scope, StorageClass, Word};
use rustc_apfloat::{ieee, Float, Round, Status};
@ -24,6 +25,7 @@ use rustc_span::Span;
use rustc_target::abi::call::FnAbi;
use rustc_target::abi::{Abi, Align, Scalar, Size, WrappingRange};
use smallvec::SmallVec;
use std::cell::Cell;
use std::convert::TryInto;
use std::iter::{self, empty};
@ -2411,18 +2413,49 @@ impl<'a, 'tcx> BuilderMethods<'a, 'tcx> for Builder<'a, 'tcx> {
// more complex and neither immediate (`fmt::Arguments` is too big)
// nor simplified in MIR (e.g. promoted to a constant) in any way,
// so we have to try and remove the `fmt::Arguments::new` call here.
#[derive(Default)]
struct DecodedFormatArgs {}
struct FormatArgsNotRecognized(String);
// HACK(eddyb) this is basically a `try` block.
let remove_format_args_if_possible = || -> Option<()> {
let try_decode_and_remove_format_args = || {
let decoded_format_args = DecodedFormatArgs::default();
let const_u32_as_usize = |ct_id| match self.builder.lookup_const_by_id(ct_id)? {
SpirvConst::U32(x) => Some(x as usize),
_ => None,
};
let const_slice_as_elem_ids = |slice_ptr_and_len_ids: &[Word]| {
if let [ptr_id, len_id] = slice_ptr_and_len_ids[..] {
if let SpirvConst::PtrTo { pointee } =
self.builder.lookup_const_by_id(ptr_id)?
{
if let SpirvConst::Composite(elems) =
self.builder.lookup_const_by_id(pointee)?
{
if elems.len() == const_u32_as_usize(len_id)? {
return Some(elems);
}
}
}
}
None
};
let format_args_id = match args {
&[
SpirvValue {
kind: SpirvValueKind::Def(format_args_id),
..
},
_,
_, // `&'static panic::Location<'static>`
] => format_args_id,
_ => return None,
_ => {
return Err(FormatArgsNotRecognized(
"panic entry-point call args".into(),
));
}
};
let custom_ext_inst_set_import = self.ext_inst.borrow_mut().import_custom(self);
@ -2446,8 +2479,11 @@ impl<'a, 'tcx> BuilderMethods<'a, 'tcx> for Builder<'a, 'tcx> {
.take_while(|inst| inst.class.opcode == Op::Variable)
.map(|inst| inst.result_id.unwrap())
.collect();
let require_local_var =
|ptr_id| Some(()).filter(|()| local_var_ids.contains(&ptr_id));
let require_local_var = |ptr_id, var| {
Some(())
.filter(|()| local_var_ids.contains(&ptr_id))
.ok_or_else(|| FormatArgsNotRecognized(format!("{var} storage not local")))
};
let mut non_debug_insts = func.blocks[block_idx]
.instructions
@ -2474,14 +2510,14 @@ impl<'a, 'tcx> BuilderMethods<'a, 'tcx> for Builder<'a, 'tcx> {
Call(ID, ID, SmallVec<[ID; 4]>),
}
let mut taken_inst_idx_range = func.blocks[block_idx].instructions.len()..;
let taken_inst_idx_range = Cell::new(func.blocks[block_idx].instructions.len())..;
// Take `count` instructions, advancing backwards, but returning
// instructions in their original order (and decoded to `Inst`s).
let mut try_rev_take = |count| {
let maybe_rev_insts = (0..count).map(|_| {
let (i, inst) = non_debug_insts.next_back()?;
taken_inst_idx_range = i..;
taken_inst_idx_range.start.set(i);
// HACK(eddyb) all instructions accepted below
// are expected to take no more than 4 operands,
@ -2519,102 +2555,143 @@ impl<'a, 'tcx> BuilderMethods<'a, 'tcx> for Builder<'a, 'tcx> {
insts.reverse();
Some(insts)
};
let fmt_args_new_call_insts = try_rev_take(3).ok_or_else(|| {
FormatArgsNotRecognized(
"fmt::Arguments::new call: ran out of instructions".into(),
)
})?;
let ((pieces_slice_ptr_id, pieces_len_id), (rt_args_slice_ptr_id, rt_args_count)) =
match fmt_args_new_call_insts[..] {
[
Inst::Call(call_ret_id, callee_id, ref call_args),
Inst::Store(st_dst_id, st_val_id),
Inst::Load(ld_val_id, ld_src_id),
] if self.fmt_args_new_fn_ids.borrow().contains(&callee_id)
&& call_ret_id == st_val_id
&& st_dst_id == ld_src_id
&& ld_val_id == format_args_id =>
{
require_local_var(st_dst_id, "fmt::Arguments::new destination")?;
let (rt_args_slice_ptr_id, rt_args_count) = match try_rev_take(3)?[..] {
[
Inst::Call(call_ret_id, callee_id, ref call_args),
Inst::Store(st_dst_id, st_val_id),
Inst::Load(ld_val_id, ld_src_id),
] if self.fmt_args_new_fn_ids.borrow().contains(&callee_id)
&& call_ret_id == st_val_id
&& st_dst_id == ld_src_id
&& ld_val_id == format_args_id =>
{
require_local_var(st_dst_id)?;
match call_args[..] {
// `<core::fmt::Arguments>::new_v1`
[_, _, rt_args_slice_ptr_id, rt_args_len_id] => (
Some(rt_args_slice_ptr_id),
self.builder
.lookup_const_by_id(rt_args_len_id)
.and_then(|ct| match ct {
SpirvConst::U32(x) => Some(x as usize),
_ => None,
})?,
),
match call_args[..] {
// `<core::fmt::Arguments>::new_v1`
[
pieces_slice_ptr_id,
pieces_len_id,
rt_args_slice_ptr_id,
rt_args_len_id,
] => (
(pieces_slice_ptr_id, pieces_len_id),
(
Some(rt_args_slice_ptr_id),
const_u32_as_usize(rt_args_len_id).ok_or_else(|| {
FormatArgsNotRecognized(
"fmt::Arguments::new: args.len() not constant"
.into(),
)
})?,
),
),
// `<core::fmt::Arguments>::new_const`
[_, _] => (None, 0),
// `<core::fmt::Arguments>::new_const`
[pieces_slice_ptr_id, pieces_len_id] => {
((pieces_slice_ptr_id, pieces_len_id), (None, 0))
}
_ => return None,
_ => {
return Err(FormatArgsNotRecognized(
"fmt::Arguments::new call args".into(),
));
}
}
}
}
_ => return None,
};
_ => {
// HACK(eddyb) this gathers more context before reporting.
let mut insts = fmt_args_new_call_insts;
insts.reverse();
while let Some(extra_inst) = try_rev_take(1) {
insts.extend(extra_inst);
if insts.len() >= 32 {
break;
}
}
insts.reverse();
return Err(FormatArgsNotRecognized(format!(
"fmt::Arguments::new call sequence ({insts:?})",
)));
}
};
// HACK(eddyb) this is the worst part: if we do have runtime
// arguments (from e.g. new `assert!`s being added to `core`),
// we have to confirm their many instructions for removal.
if rt_args_count > 0 {
let rt_args_slice_ptr_id = rt_args_slice_ptr_id.unwrap();
let rt_args_array_ptr_id = match try_rev_take(1)?[..] {
[Inst::Bitcast(out_id, in_id)] if out_id == rt_args_slice_ptr_id => in_id,
_ => return None,
};
require_local_var(rt_args_array_ptr_id);
// Each runtime argument has its own variable, 6 instructions
// to initialize it, and 9 instructions to copy it to the
// appropriate slot in the array. The groups of 6 and 9
// instructions, for all runtime args, are each separate.
let copies_from_rt_arg_vars_to_rt_args_array = try_rev_take(rt_args_count * 9)?;
let copies_from_rt_arg_vars_to_rt_args_array =
copies_from_rt_arg_vars_to_rt_args_array.chunks(9);
let inits_of_rt_arg_vars = try_rev_take(rt_args_count * 6)?;
let inits_of_rt_arg_vars = inits_of_rt_arg_vars.chunks(6);
for (
rt_arg_idx,
(init_of_rt_arg_var_insts, copy_from_rt_arg_var_to_rt_args_array_insts),
) in inits_of_rt_arg_vars
.zip(copies_from_rt_arg_vars_to_rt_args_array)
.enumerate()
let rt_args_array_ptr_id = match try_rev_take(1).ok_or_else(|| {
FormatArgsNotRecognized(
"&[fmt::rt::Argument] bitcast: ran out of instructions".into(),
)
})?[..]
{
let rt_arg_var_id = match init_of_rt_arg_var_insts[..] {
[
Inst::Bitcast(b, _),
Inst::Bitcast(a, _),
Inst::AccessChain(a_ptr, a_base_ptr, SpirvConst::U32(0)),
Inst::Store(a_st_dst, a_st_val),
Inst::AccessChain(b_ptr, b_base_ptr, SpirvConst::U32(1)),
Inst::Store(b_st_dst, b_st_val),
] if a_base_ptr == b_base_ptr
&& (a, b) == (a_st_val, b_st_val)
&& (a_ptr, b_ptr) == (a_st_dst, b_st_dst) =>
{
require_local_var(a_base_ptr);
a_base_ptr
}
_ => return None,
};
[Inst::Bitcast(out_id, in_id)] if out_id == rt_args_slice_ptr_id => in_id,
_ => {
return Err(FormatArgsNotRecognized(
"&[fmt::rt::Argument] bitcast".into(),
));
}
};
require_local_var(rt_args_array_ptr_id, "[fmt::rt::Argument; N]")?;
// HACK(eddyb) this is only split to allow variable name reuse.
let (copy_loads, copy_stores) =
copy_from_rt_arg_var_to_rt_args_array_insts.split_at(4);
let (a, b) = match copy_loads[..] {
// Each runtime argument has 3 instructions to call one of
// the `fmt::rt::Argument::new_*` functions (and split its
// scalar pair result), and 5 instructions to store it into
// the appropriate slot in the array. The groups of 3 and 5
// instructions, for all runtime args, are each separate.
let stores_to_rt_args_array =
try_rev_take(rt_args_count * 5).ok_or_else(|| {
FormatArgsNotRecognized(
"[fmt::rt::Argument; N] stores: ran out of instructions".into(),
)
})?;
let stores_to_rt_args_array = stores_to_rt_args_array.chunks(5);
let rt_arg_new_calls = try_rev_take(rt_args_count * 3).ok_or_else(|| {
FormatArgsNotRecognized(
"fmt::rt::Argument::new calls: ran out of instructions".into(),
)
})?;
let rt_arg_new_calls = rt_arg_new_calls.chunks(3);
for (rt_arg_idx, (rt_arg_new_call_insts, store_to_rt_args_array_insts)) in
rt_arg_new_calls.zip(stores_to_rt_args_array).enumerate()
{
let (a, b) = match rt_arg_new_call_insts[..] {
[
Inst::AccessChain(a_ptr, a_base_ptr, SpirvConst::U32(0)),
Inst::Load(a_ld_val, a_ld_src),
Inst::AccessChain(b_ptr, b_base_ptr, SpirvConst::U32(1)),
Inst::Load(b_ld_val, b_ld_src),
] if [a_base_ptr, b_base_ptr] == [rt_arg_var_id; 2]
&& (a_ptr, b_ptr) == (a_ld_src, b_ld_src) =>
{
(a_ld_val, b_ld_val)
}
_ => return None,
};
match copy_stores[..] {
Inst::Call(call_ret_id, callee_id, ref call_args),
Inst::CompositeExtract(a, a_parent_pair, 0),
Inst::CompositeExtract(b, b_parent_pair, 1),
] if [a_parent_pair, b_parent_pair] == [call_ret_id; 2] => self
.fmt_rt_arg_new_fn_ids_to_ty_and_spec
.borrow()
.get(&callee_id)
.and_then(|&(ty, spec)| match call_args[..] {
[x] => {
decoded_format_args
.ref_arg_ids_with_ty_and_spec
.push((x, ty, spec));
Some((a, b))
}
_ => None,
}),
_ => None,
}
.ok_or_else(|| {
FormatArgsNotRecognized(format!(
"fmt::rt::Argument::new call sequence ({rt_arg_new_call_insts:?})"
))
})?;
match store_to_rt_args_array_insts[..] {
[
Inst::InBoundsAccessChain(
array_slot_ptr,
@ -2630,7 +2707,11 @@ impl<'a, 'tcx> BuilderMethods<'a, 'tcx> for Builder<'a, 'tcx> {
&& [a_base_ptr, b_base_ptr] == [array_slot_ptr; 2]
&& (a, b) == (a_st_val, b_st_val)
&& (a_ptr, b_ptr) == (a_st_dst, b_st_dst) => {}
_ => return None,
_ => {
return Err(FormatArgsNotRecognized(format!(
"[fmt::rt::Argument; N] stores sequence ({store_to_rt_args_array_insts:?})"
)));
}
}
}
}
@ -2639,11 +2720,36 @@ impl<'a, 'tcx> BuilderMethods<'a, 'tcx> for Builder<'a, 'tcx> {
// confirmed above to be the first instruction of `format_args!`.
func.blocks[block_idx]
.instructions
.truncate(taken_inst_idx_range.start);
.truncate(taken_inst_idx_range.start.get());
None
Ok(decoded_format_args)
};
remove_format_args_if_possible();
match try_decode_and_remove_format_args() {
Ok(DecodedFormatArgs {}) => {}
Err(FormatArgsNotRecognized(step)) => {
if let Some(current_span) = self.current_span {
let mut warn = self.tcx.sess.struct_span_warn(
current_span,
"failed to find and remove `format_args!` construction for this `panic!`",
);
warn.note(
"compilation may later fail due to leftover `format_args!` internals",
);
if self.tcx.sess.opts.unstable_opts.inline_mir != Some(true) {
warn.note("missing `-Zinline-mir=on` flag (should've been set by `spirv-builder`)")
.help("check `.cargo` and environment variables for potential overrides")
.help("(or, if not using `spirv-builder` at all, add the flag manually)");
} else {
warn.note(format!("[RUST-GPU BUG] bailed from {step}"));
}
warn.emit();
}
}
}
// HACK(eddyb) redirect any possible panic call to an abort, to avoid
// needing to materialize `&core::panic::Location` or `format_args!`.

32
crates/rustc_codegen_spirv/src/codegen_cx/declare.rs
View File

@ -4,6 +4,7 @@ use crate::attr::AggregatedSpirvAttributes;
use crate::builder_spirv::{SpirvConst, SpirvValue, SpirvValueExt};
use crate::custom_decorations::{CustomDecoration, SrcLocDecoration};
use crate::spirv_type::SpirvType;
use itertools::Itertools;
use rspirv::spirv::{FunctionControl, LinkageType, StorageClass, Word};
use rustc_attr::InlineAttr;
use rustc_codegen_ssa::traits::{BaseTypeMethods, PreDefineMethods, StaticMethods};
@ -177,15 +178,13 @@ impl<'tcx> CodegenCx<'tcx> {
if [
self.tcx.lang_items().panic_fn(),
self.tcx.lang_items().panic_fmt(),
self.tcx.lang_items().panic_display(),
self.tcx.lang_items().panic_bounds_check_fn(),
]
.contains(&Some(instance_def_id))
{
self.panic_entry_point_ids.borrow_mut().insert(fn_id);
}
// HACK(eddyb) there is no good way to identify this definition
// HACK(eddyb) there is no good way to identify these definitions
// (e.g. no `#[lang = "..."]` attribute), but this works well enough.
if [
"<core::fmt::Arguments>::new_v1",
@ -196,6 +195,33 @@ impl<'tcx> CodegenCx<'tcx> {
self.fmt_args_new_fn_ids.borrow_mut().insert(fn_id);
}
// HACK(eddyb) there is no good way to identify these definitions
// (e.g. no `#[lang = "..."]` attribute), but this works well enough.
if let Some(suffix) = demangled_symbol_name.strip_prefix("<core::fmt::rt::Argument>::new_")
{
let spec = suffix.split_once("::<").and_then(|(method_suffix, _)| {
Some(match method_suffix {
"display" => ' ',
"debug" => '?',
"octal" => 'o',
"lower_hex" => 'x',
"upper_hex" => 'X',
"pointer" => 'p',
"binary" => 'b',
"lower_exp" => 'e',
"upper_exp" => 'E',
_ => return None,
})
});
if let Some(spec) = spec {
if let Some((ty,)) = instance.substs.types().collect_tuple() {
self.fmt_rt_arg_new_fn_ids_to_ty_and_spec
.borrow_mut()
.insert(fn_id, (ty, spec));
}
}
}
declared
}

13
crates/rustc_codegen_spirv/src/codegen_cx/mod.rs
View File

@ -61,17 +61,17 @@ pub struct CodegenCx<'tcx> {
pub libm_intrinsics: RefCell<FxHashMap<Word, super::builder::libm_intrinsics::LibmIntrinsic>>,
/// All `panic!(...)`s and builtin panics (from MIR `Assert`s) call into one
/// of these lang items, which we always replace with an "abort", erasing
/// anything passed in.
//
// FIXME(eddyb) we should not erase anywhere near as much, but `format_args!`
// is not representable due to containg Rust slices, and Rust 2021 has made
// it mandatory even for `panic!("...")` (that were previously separate).
/// of these lang items, which we always replace with an "abort".
pub panic_entry_point_ids: RefCell<FxHashSet<Word>>,
/// `core::fmt::Arguments::new_{v1,const}` instances (for Rust 2021 panics).
pub fmt_args_new_fn_ids: RefCell<FxHashSet<Word>>,
/// `core::fmt::rt::Argument::new_*::<T>` instances (for panics' `format_args!`),
/// with their `T` type (i.e. of the value being formatted), and formatting
/// "specifier" as a `char` (' ' for `Display`, `x` for `LowerHex`, etc.)
pub fmt_rt_arg_new_fn_ids_to_ty_and_spec: RefCell<FxHashMap<Word, (Ty<'tcx>, char)>>,
/// Intrinsic for loading a <T> from a &[u32]. The PassMode is the mode of the <T>.
pub buffer_load_intrinsic_fn_id: RefCell<FxHashMap<Word, &'tcx PassMode>>,
/// Intrinsic for storing a <T> into a &[u32]. The PassMode is the mode of the <T>.
@ -131,6 +131,7 @@ impl<'tcx> CodegenCx<'tcx> {
libm_intrinsics: Default::default(),
panic_entry_point_ids: Default::default(),
fmt_args_new_fn_ids: Default::default(),
fmt_rt_arg_new_fn_ids_to_ty_and_spec: Default::default(),
buffer_load_intrinsic_fn_id: Default::default(),
buffer_store_intrinsic_fn_id: Default::default(),
i8_i16_atomics_allowed: false,

3
crates/spirv-builder/src/lib.rs
View File

@ -562,6 +562,9 @@ fn invoke_rustc(builder: &SpirvBuilder) -> Result<PathBuf, SpirvBuilderError> {
// ensures no unwanted surprises from e.g. `core` debug assertions.
"-Coverflow-checks=off".to_string(),
"-Cdebug-assertions=off".to_string(),
// HACK(eddyb) we need this for `core::fmt::rt::Argument::new_*` calls
// to *never* be inlined, so we can pattern-match the calls themselves.
"-Zinline-mir=off".to_string(),
];
// Wrapper for `env::var` that appropriately informs Cargo of the dependency.

16
tests/src/main.rs
View File

@ -346,14 +346,20 @@ fn rust_flags(codegen_backend_path: &Path) -> String {
// to rebuild crates compiled with it when it changes (this used to be
// the default until https://github.com/rust-lang/rust/pull/93969).
"-Zbinary-dep-depinfo",
"-Coverflow-checks=off",
"-Cdebug-assertions=off",
"-Cdebuginfo=2",
"-Cembed-bitcode=no",
&format!("-Ctarget-feature=+{}", target_features.join(",+")),
"-Csymbol-mangling-version=v0",
"-Zcrate-attr=feature(register_tool)",
"-Zcrate-attr=register_tool(rust_gpu)",
// HACK(eddyb) this is the same configuration that we test with, and
// ensures no unwanted surprises from e.g. `core` debug assertions.
"-Coverflow-checks=off",
"-Cdebug-assertions=off",
// HACK(eddyb) we need this for `core::fmt::rt::Argument::new_*` calls
// to *never* be inlined, so we can pattern-match the calls themselves.
"-Zinline-mir=off",
// NOTE(eddyb) flags copied from `spirv-builder` are all above this line.
"-Cdebuginfo=2",
"-Cembed-bitcode=no",
&format!("-Ctarget-feature=+{}", target_features.join(",+")),
]
.join(" ")
}