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Auto merge of #85546 - hyd-dev:unwind, r=RalfJung

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const-eval: disallow unwinding across functions that `!fn_can_unwind()`

Following https://github.com/rust-lang/miri/pull/1776#discussion_r633074343, so r? `@RalfJung`

This PR turns `unwind` in `StackPopCleanup::Goto` into a new enum `StackPopUnwind`, with a `NotAllowed` variant to indicate that unwinding is not allowed. This variant is chosen based on `rustc_middle::ty::layout::fn_can_unwind()` in `eval_fn_call()` when pushing the frame. A check is added in `unwind_to_block()` to report UB if unwinding happens across a `StackPopUnwind::NotAllowed` frame.

Tested with Miri `HEAD` with [minor changes](https://github.com/rust-lang/miri/compare/HEAD..9cf3c7f0d86325a586fbcbf2acdc9232b861f1d8) and the rust-lang/miri#1776 branch with [these changes](d866c1c52f..626638fbfe).
This commit is contained in:
bors 2021-05-28 08:49:48 +00:00
commit ce0d64e03e
7 changed files with 168 additions and 94 deletions
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75
compiler/rustc_middle/src/ty/layout.rs
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@ -2579,7 +2579,7 @@ where
fn adjust_for_abi(&mut self, cx: &C, abi: SpecAbi);
}
fn fn_can_unwind(
pub fn fn_can_unwind(
panic_strategy: PanicStrategy,
codegen_fn_attr_flags: CodegenFnAttrFlags,
call_conv: Conv,
@ -2641,6 +2641,43 @@ fn fn_can_unwind(
}
}
pub fn conv_from_spec_abi(tcx: TyCtxt<'_>, abi: SpecAbi) -> Conv {
use rustc_target::spec::abi::Abi::*;
match tcx.sess.target.adjust_abi(abi) {
RustIntrinsic | PlatformIntrinsic | Rust | RustCall => Conv::Rust,
// It's the ABI's job to select this, not ours.
System { .. } => bug!("system abi should be selected elsewhere"),
EfiApi => bug!("eficall abi should be selected elsewhere"),
Stdcall { .. } => Conv::X86Stdcall,
Fastcall => Conv::X86Fastcall,
Vectorcall => Conv::X86VectorCall,
Thiscall { .. } => Conv::X86ThisCall,
C { .. } => Conv::C,
Unadjusted => Conv::C,
Win64 => Conv::X86_64Win64,
SysV64 => Conv::X86_64SysV,
Aapcs => Conv::ArmAapcs,
CCmseNonSecureCall => Conv::CCmseNonSecureCall,
PtxKernel => Conv::PtxKernel,
Msp430Interrupt => Conv::Msp430Intr,
X86Interrupt => Conv::X86Intr,
AmdGpuKernel => Conv::AmdGpuKernel,
AvrInterrupt => Conv::AvrInterrupt,
AvrNonBlockingInterrupt => Conv::AvrNonBlockingInterrupt,
Wasm => Conv::C,
// These API constants ought to be more specific...
Cdecl => Conv::C,
}
}
pub fn fn_ptr_codegen_fn_attr_flags() -> CodegenFnAttrFlags {
// Assume that fn pointers may always unwind
CodegenFnAttrFlags::UNWIND
}
impl<'tcx, C> FnAbiExt<'tcx, C> for call::FnAbi<'tcx, Ty<'tcx>>
where
C: LayoutOf<Ty = Ty<'tcx>, TyAndLayout = TyAndLayout<'tcx>>
@ -2650,10 +2687,7 @@ where
+ HasParamEnv<'tcx>,
{
fn of_fn_ptr(cx: &C, sig: ty::PolyFnSig<'tcx>, extra_args: &[Ty<'tcx>]) -> Self {
// Assume that fn pointers may always unwind
let codegen_fn_attr_flags = CodegenFnAttrFlags::UNWIND;
call::FnAbi::new_internal(cx, sig, extra_args, None, codegen_fn_attr_flags, false)
call::FnAbi::new_internal(cx, sig, extra_args, None, fn_ptr_codegen_fn_attr_flags(), false)
}
fn of_instance(cx: &C, instance: ty::Instance<'tcx>, extra_args: &[Ty<'tcx>]) -> Self {
@ -2689,35 +2723,7 @@ where
let sig = cx.tcx().normalize_erasing_late_bound_regions(ty::ParamEnv::reveal_all(), sig);
use rustc_target::spec::abi::Abi::*;
let conv = match cx.tcx().sess.target.adjust_abi(sig.abi) {
RustIntrinsic | PlatformIntrinsic | Rust | RustCall => Conv::Rust,
// It's the ABI's job to select this, not ours.
System { .. } => bug!("system abi should be selected elsewhere"),
EfiApi => bug!("eficall abi should be selected elsewhere"),
Stdcall { .. } => Conv::X86Stdcall,
Fastcall => Conv::X86Fastcall,
Vectorcall => Conv::X86VectorCall,
Thiscall { .. } => Conv::X86ThisCall,
C { .. } => Conv::C,
Unadjusted => Conv::C,
Win64 => Conv::X86_64Win64,
SysV64 => Conv::X86_64SysV,
Aapcs => Conv::ArmAapcs,
CCmseNonSecureCall => Conv::CCmseNonSecureCall,
PtxKernel => Conv::PtxKernel,
Msp430Interrupt => Conv::Msp430Intr,
X86Interrupt => Conv::X86Intr,
AmdGpuKernel => Conv::AmdGpuKernel,
AvrInterrupt => Conv::AvrInterrupt,
AvrNonBlockingInterrupt => Conv::AvrNonBlockingInterrupt,
Wasm => Conv::C,
// These API constants ought to be more specific...
Cdecl => Conv::C,
};
let conv = conv_from_spec_abi(cx.tcx(), sig.abi);
let mut inputs = sig.inputs();
let extra_args = if sig.abi == RustCall {
@ -2753,6 +2759,7 @@ where
target.os == "linux" && target.arch == "sparc64" && target_env_gnu_like;
let linux_powerpc_gnu_like =
target.os == "linux" && target.arch == "powerpc" && target_env_gnu_like;
use SpecAbi::*;
let rust_abi = matches!(sig.abi, RustIntrinsic | PlatformIntrinsic | Rust | RustCall);
// Handle safe Rust thin and fat pointers.