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RalfJungRalfJung
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refactor extern static handling
1 parent cf22ee0 commit cba1fdb

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4 files changed

+82
-73
lines changed

4 files changed

+82
-73
lines changed

‎src/tools/miri/ci/ci.sh

Lines changed: 2 additions & 3 deletions
Original file line numberDiff line numberDiff line change
@@ -121,9 +121,8 @@ case $HOST_TARGET in
121121
MIRI_TEST_TARGET=aarch64-apple-darwin run_tests
122122
MIRI_TEST_TARGET=i686-pc-windows-gnu run_tests
123123
# Some targets are only partially supported.
124-
# FIXME: freeBSD disabled due to https://github.com/rust-lang/miri/issues/3276
125-
#MIRI_TEST_TARGET=x86_64-unknown-freebsd run_tests_minimal hello integer vec panic/panic concurrency/simple pthread-threadname libc-getentropy libc-getrandom libc-misc libc-fs atomic env align
126-
#MIRI_TEST_TARGET=i686-unknown-freebsd run_tests_minimal hello integer vec panic/panic concurrency/simple pthread-threadname libc-getentropy libc-getrandom libc-misc libc-fs atomic env align
124+
MIRI_TEST_TARGET=x86_64-unknown-freebsd run_tests_minimal hello integer vec panic/panic concurrency/simple pthread-threadname libc-getentropy libc-getrandom libc-misc libc-fs atomic env align
125+
MIRI_TEST_TARGET=i686-unknown-freebsd run_tests_minimal hello integer vec panic/panic concurrency/simple pthread-threadname libc-getentropy libc-getrandom libc-misc libc-fs atomic env align
127126
MIRI_TEST_TARGET=aarch64-linux-android run_tests_minimal hello integer vec panic/panic
128127
MIRI_TEST_TARGET=wasm32-wasi run_tests_minimal no_std integer strings wasm
129128
MIRI_TEST_TARGET=wasm32-unknown-unknown run_tests_minimal no_std integer strings wasm

‎src/tools/miri/src/machine.rs

Lines changed: 1 addition & 70 deletions
Original file line numberDiff line numberDiff line change
@@ -691,7 +691,7 @@ impl<'mir, 'tcx> MiriMachine<'mir, 'tcx> {
691691
Ok(())
692692
}
693693

694-
fn add_extern_static(
694+
pub(crate) fn add_extern_static(
695695
this: &mut MiriInterpCx<'mir, 'tcx>,
696696
name: &str,
697697
ptr: Pointer<Option<Provenance>>,
@@ -701,75 +701,6 @@ impl<'mir, 'tcx> MiriMachine<'mir, 'tcx> {
701701
this.machine.extern_statics.try_insert(Symbol::intern(name), ptr).unwrap();
702702
}
703703

704-
fn alloc_extern_static(
705-
this: &mut MiriInterpCx<'mir, 'tcx>,
706-
name: &str,
707-
val: ImmTy<'tcx, Provenance>,
708-
) -> InterpResult<'tcx> {
709-
let place = this.allocate(val.layout, MiriMemoryKind::ExternStatic.into())?;
710-
this.write_immediate(*val, &place)?;
711-
Self::add_extern_static(this, name, place.ptr());
712-
Ok(())
713-
}
714-
715-
/// Sets up the "extern statics" for this machine.
716-
fn init_extern_statics(this: &mut MiriInterpCx<'mir, 'tcx>) -> InterpResult<'tcx> {
717-
// "__rust_no_alloc_shim_is_unstable"
718-
let val = ImmTy::from_int(0, this.machine.layouts.u8);
719-
Self::alloc_extern_static(this, "__rust_no_alloc_shim_is_unstable", val)?;
720-
721-
match this.tcx.sess.target.os.as_ref() {
722-
"linux" => {
723-
// "environ"
724-
Self::add_extern_static(
725-
this,
726-
"environ",
727-
this.machine.env_vars.environ.as_ref().unwrap().ptr(),
728-
);
729-
// A couple zero-initialized pointer-sized extern statics.
730-
// Most of them are for weak symbols, which we all set to null (indicating that the
731-
// symbol is not supported, and triggering fallback code which ends up calling a
732-
// syscall that we do support).
733-
for name in &["__cxa_thread_atexit_impl", "getrandom", "statx", "__clock_gettime64"]
734-
{
735-
let val = ImmTy::from_int(0, this.machine.layouts.usize);
736-
Self::alloc_extern_static(this, name, val)?;
737-
}
738-
}
739-
"freebsd" => {
740-
// "environ"
741-
Self::add_extern_static(
742-
this,
743-
"environ",
744-
this.machine.env_vars.environ.as_ref().unwrap().ptr(),
745-
);
746-
}
747-
"android" => {
748-
// "signal" -- just needs a non-zero pointer value (function does not even get called),
749-
// but we arrange for this to be callable anyway (it will then do nothing).
750-
let layout = this.machine.layouts.const_raw_ptr;
751-
let ptr = this.fn_ptr(FnVal::Other(DynSym::from_str("signal")));
752-
let val = ImmTy::from_scalar(Scalar::from_pointer(ptr, this), layout);
753-
Self::alloc_extern_static(this, "signal", val)?;
754-
// A couple zero-initialized pointer-sized extern statics.
755-
// Most of them are for weak symbols, which we all set to null (indicating that the
756-
// symbol is not supported, and triggering fallback code.)
757-
for name in &["bsd_signal"] {
758-
let val = ImmTy::from_int(0, this.machine.layouts.usize);
759-
Self::alloc_extern_static(this, name, val)?;
760-
}
761-
}
762-
"windows" => {
763-
// "_tls_used"
764-
// This is some obscure hack that is part of the Windows TLS story. It's a `u8`.
765-
let val = ImmTy::from_int(0, this.machine.layouts.u8);
766-
Self::alloc_extern_static(this, "_tls_used", val)?;
767-
}
768-
_ => {} // No "extern statics" supported on this target
769-
}
770-
Ok(())
771-
}
772-
773704
pub(crate) fn communicate(&self) -> bool {
774705
self.isolated_op == IsolatedOp::Allow
775706
}

‎src/tools/miri/src/shims/extern_static.rs

Lines changed: 78 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -0,0 +1,78 @@
1+
//! Provides the `extern static` that this platform expects.
2+
3+
use crate::*;
4+
5+
impl<'mir, 'tcx> MiriMachine<'mir, 'tcx> {
6+
fn alloc_extern_static(
7+
this: &mut MiriInterpCx<'mir, 'tcx>,
8+
name: &str,
9+
val: ImmTy<'tcx, Provenance>,
10+
) -> InterpResult<'tcx> {
11+
let place = this.allocate(val.layout, MiriMemoryKind::ExternStatic.into())?;
12+
this.write_immediate(*val, &place)?;
13+
Self::add_extern_static(this, name, place.ptr());
14+
Ok(())
15+
}
16+
17+
/// Zero-initialized pointer-sized extern statics are pretty common.
18+
/// Most of them are for weak symbols, which we all set to null (indicating that the
19+
/// symbol is not supported, and triggering fallback code which ends up calling a
20+
/// syscall that we do support).
21+
fn null_ptr_extern_statics(
22+
this: &mut MiriInterpCx<'mir, 'tcx>,
23+
names: &[&str],
24+
) -> InterpResult<'tcx> {
25+
for name in names {
26+
let val = ImmTy::from_int(0, this.machine.layouts.usize);
27+
Self::alloc_extern_static(this, name, val)?;
28+
}
29+
Ok(())
30+
}
31+
32+
/// Sets up the "extern statics" for this machine.
33+
pub fn init_extern_statics(this: &mut MiriInterpCx<'mir, 'tcx>) -> InterpResult<'tcx> {
34+
// "__rust_no_alloc_shim_is_unstable"
35+
let val = ImmTy::from_int(0, this.machine.layouts.u8);
36+
Self::alloc_extern_static(this, "__rust_no_alloc_shim_is_unstable", val)?;
37+
38+
match this.tcx.sess.target.os.as_ref() {
39+
"linux" => {
40+
Self::null_ptr_extern_statics(
41+
this,
42+
&["__cxa_thread_atexit_impl", "getrandom", "statx", "__clock_gettime64"],
43+
)?;
44+
// "environ"
45+
Self::add_extern_static(
46+
this,
47+
"environ",
48+
this.machine.env_vars.environ.as_ref().unwrap().ptr(),
49+
);
50+
}
51+
"freebsd" => {
52+
// "environ"
53+
Self::add_extern_static(
54+
this,
55+
"environ",
56+
this.machine.env_vars.environ.as_ref().unwrap().ptr(),
57+
);
58+
}
59+
"android" => {
60+
Self::null_ptr_extern_statics(this, &["bsd_signal"])?;
61+
// "signal" -- just needs a non-zero pointer value (function does not even get called),
62+
// but we arrange for this to call the `signal` function anyway.
63+
let layout = this.machine.layouts.const_raw_ptr;
64+
let ptr = this.fn_ptr(FnVal::Other(DynSym::from_str("signal")));
65+
let val = ImmTy::from_scalar(Scalar::from_pointer(ptr, this), layout);
66+
Self::alloc_extern_static(this, "signal", val)?;
67+
}
68+
"windows" => {
69+
// "_tls_used"
70+
// This is some obscure hack that is part of the Windows TLS story. It's a `u8`.
71+
let val = ImmTy::from_int(0, this.machine.layouts.u8);
72+
Self::alloc_extern_static(this, "_tls_used", val)?;
73+
}
74+
_ => {} // No "extern statics" supported on this target
75+
}
76+
Ok(())
77+
}
78+
}

‎src/tools/miri/src/shims/mod.rs

Lines changed: 1 addition & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -10,6 +10,7 @@ pub mod windows;
1010
mod x86;
1111

1212
pub mod env;
13+
pub mod extern_static;
1314
pub mod os_str;
1415
pub mod panic;
1516
pub mod time;

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