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Fix allocator shim handling in miri

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This commit is contained in:
bjorn3 2023-02-12 12:01:18 +00:00
parent 8ea28a4132
commit 9506011d32
2 changed files with 32 additions and 31 deletions
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4
src/tools/miri/src/machine.rs
View File

@ -635,6 +635,10 @@ impl<'mir, 'tcx> MiriMachine<'mir, 'tcx> {
/// Sets up the "extern statics" for this machine.
fn init_extern_statics(this: &mut MiriInterpCx<'mir, 'tcx>) -> InterpResult<'tcx> {
// "__rust_no_alloc_shim_is_unstable"
let val = ImmTy::from_int(0, this.machine.layouts.u8);
Self::alloc_extern_static(this, "__rust_no_alloc_shim_is_unstable", val)?;
match this.tcx.sess.target.os.as_ref() {
"linux" => {
// "environ"

59
src/tools/miri/src/shims/foreign_items.rs
View File

@ -347,7 +347,6 @@ pub trait EvalContextExt<'mir, 'tcx: 'mir>: crate::MiriInterpCxExt<'mir, 'tcx> {
/// Emulates calling the internal __rust_* allocator functions
fn emulate_allocator(
&mut self,
symbol: Symbol,
default: impl FnOnce(&mut MiriInterpCx<'mir, 'tcx>) -> InterpResult<'tcx>,
) -> InterpResult<'tcx, EmulateByNameResult<'mir, 'tcx>> {
let this = self.eval_context_mut();
@ -359,11 +358,8 @@ pub trait EvalContextExt<'mir, 'tcx: 'mir>: crate::MiriInterpCxExt<'mir, 'tcx> {
match allocator_kind {
AllocatorKind::Global => {
let (body, instance) = this
.lookup_exported_symbol(symbol)?
.expect("symbol should be present if there is a global allocator");
Ok(EmulateByNameResult::MirBody(body, instance))
// `__rust_*` is defined by `#[global_allocator]` if `#[global_allocator]` is used
return Ok(EmulateByNameResult::NotSupported);
}
AllocatorKind::Default => {
default(this)?;
@ -558,11 +554,11 @@ pub trait EvalContextExt<'mir, 'tcx: 'mir>: crate::MiriInterpCxExt<'mir, 'tcx> {
// Rust allocation
"__rust_alloc" | "miri_alloc" => {
let [size, align] = this.check_shim(abi, Abi::Rust, link_name, args)?;
let size = this.read_target_usize(size)?;
let align = this.read_target_usize(align)?;
let default = |this: &mut MiriInterpCx<'mir, 'tcx>| {
let [size, align] = this.check_shim(abi, Abi::Rust, link_name, args)?;
let size = this.read_target_usize(size)?;
let align = this.read_target_usize(align)?;
Self::check_alloc_request(size, align)?;
let memory_kind = match link_name.as_str() {
@ -581,8 +577,7 @@ pub trait EvalContextExt<'mir, 'tcx: 'mir>: crate::MiriInterpCxExt<'mir, 'tcx> {
};
match link_name.as_str() {
"__rust_alloc" =>
return this.emulate_allocator(Symbol::intern("__rg_alloc"), default),
"__rust_alloc" => return this.emulate_allocator(default),
"miri_alloc" => {
default(this)?;
return Ok(EmulateByNameResult::NeedsJumping);
@ -591,11 +586,11 @@ pub trait EvalContextExt<'mir, 'tcx: 'mir>: crate::MiriInterpCxExt<'mir, 'tcx> {
}
}
"__rust_alloc_zeroed" => {
let [size, align] = this.check_shim(abi, Abi::Rust, link_name, args)?;
let size = this.read_target_usize(size)?;
let align = this.read_target_usize(align)?;
return this.emulate_allocator(|this| {
let [size, align] = this.check_shim(abi, Abi::Rust, link_name, args)?;
let size = this.read_target_usize(size)?;
let align = this.read_target_usize(align)?;
return this.emulate_allocator(Symbol::intern("__rg_alloc_zeroed"), |this| {
Self::check_alloc_request(size, align)?;
let ptr = this.allocate_ptr(
@ -614,12 +609,13 @@ pub trait EvalContextExt<'mir, 'tcx: 'mir>: crate::MiriInterpCxExt<'mir, 'tcx> {
});
}
"__rust_dealloc" | "miri_dealloc" => {
let [ptr, old_size, align] = this.check_shim(abi, Abi::Rust, link_name, args)?;
let ptr = this.read_pointer(ptr)?;
let old_size = this.read_target_usize(old_size)?;
let align = this.read_target_usize(align)?;
let default = |this: &mut MiriInterpCx<'mir, 'tcx>| {
let [ptr, old_size, align] =
this.check_shim(abi, Abi::Rust, link_name, args)?;
let ptr = this.read_pointer(ptr)?;
let old_size = this.read_target_usize(old_size)?;
let align = this.read_target_usize(align)?;
let memory_kind = match link_name.as_str() {
"__rust_dealloc" => MiriMemoryKind::Rust,
"miri_dealloc" => MiriMemoryKind::Miri,
@ -635,8 +631,9 @@ pub trait EvalContextExt<'mir, 'tcx: 'mir>: crate::MiriInterpCxExt<'mir, 'tcx> {
};
match link_name.as_str() {
"__rust_dealloc" =>
return this.emulate_allocator(Symbol::intern("__rg_dealloc"), default),
"__rust_dealloc" => {
return this.emulate_allocator(default);
}
"miri_dealloc" => {
default(this)?;
return Ok(EmulateByNameResult::NeedsJumping);
@ -645,15 +642,15 @@ pub trait EvalContextExt<'mir, 'tcx: 'mir>: crate::MiriInterpCxExt<'mir, 'tcx> {
}
}
"__rust_realloc" => {
let [ptr, old_size, align, new_size] =
this.check_shim(abi, Abi::Rust, link_name, args)?;
let ptr = this.read_pointer(ptr)?;
let old_size = this.read_target_usize(old_size)?;
let align = this.read_target_usize(align)?;
let new_size = this.read_target_usize(new_size)?;
// No need to check old_size; we anyway check that they match the allocation.
return this.emulate_allocator(|this| {
let [ptr, old_size, align, new_size] =
this.check_shim(abi, Abi::Rust, link_name, args)?;
let ptr = this.read_pointer(ptr)?;
let old_size = this.read_target_usize(old_size)?;
let align = this.read_target_usize(align)?;
let new_size = this.read_target_usize(new_size)?;
// No need to check old_size; we anyway check that they match the allocation.
return this.emulate_allocator(Symbol::intern("__rg_realloc"), |this| {
Self::check_alloc_request(new_size, align)?;
let align = Align::from_bytes(align).unwrap();