blob: 41c22de1186ebc12d2d27afb4fe3445a35ab0e06 [file] [log] [blame]
use super::{RawConst, Pointer, CheckInAllocMsg, ScalarMaybeUndef};
use crate::hir;
use crate::hir::map::definitions::DefPathData;
use crate::mir;
use crate::ty::{self, Ty, layout};
use crate::ty::layout::{Size, Align, LayoutError};
use crate::ty::query::TyCtxtAt;
use backtrace::Backtrace;
use errors::DiagnosticBuilder;
use rustc_macros::HashStable;
use rustc_target::spec::abi::Abi;
use syntax_pos::{Pos, Span};
use syntax::symbol::Symbol;
use hir::GeneratorKind;
use std::{fmt, env};
use rustc_error_codes::*;
#[derive(Debug, Copy, Clone, PartialEq, Eq, HashStable, RustcEncodable, RustcDecodable)]
pub enum ErrorHandled {
/// Already reported a lint or an error for this evaluation.
Reported,
/// Don't emit an error, the evaluation failed because the MIR was generic
/// and the substs didn't fully monomorphize it.
TooGeneric,
}
impl ErrorHandled {
pub fn assert_reported(self) {
match self {
ErrorHandled::Reported => {},
ErrorHandled::TooGeneric => bug!("MIR interpretation failed without reporting an error \
even though it was fully monomorphized"),
}
}
}
CloneTypeFoldableImpls! {
ErrorHandled,
}
pub type ConstEvalRawResult<'tcx> = Result<RawConst<'tcx>, ErrorHandled>;
pub type ConstEvalResult<'tcx> = Result<&'tcx ty::Const<'tcx>, ErrorHandled>;
#[derive(Clone, Debug)]
pub struct ConstEvalErr<'tcx> {
pub span: Span,
pub error: crate::mir::interpret::InterpError<'tcx>,
pub stacktrace: Vec<FrameInfo<'tcx>>,
}
#[derive(Clone, Debug)]
pub struct FrameInfo<'tcx> {
/// This span is in the caller.
pub call_site: Span,
pub instance: ty::Instance<'tcx>,
pub lint_root: Option<hir::HirId>,
}
impl<'tcx> fmt::Display for FrameInfo<'tcx> {
fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
ty::tls::with(|tcx| {
if tcx.def_key(self.instance.def_id()).disambiguated_data.data
== DefPathData::ClosureExpr
{
write!(f, "inside call to closure")?;
} else {
write!(f, "inside call to `{}`", self.instance)?;
}
if !self.call_site.is_dummy() {
let lo = tcx.sess.source_map().lookup_char_pos(self.call_site.lo());
write!(f, " at {}:{}:{}", lo.file.name, lo.line, lo.col.to_usize() + 1)?;
}
Ok(())
})
}
}
impl<'tcx> ConstEvalErr<'tcx> {
pub fn struct_error(
&self,
tcx: TyCtxtAt<'tcx>,
message: &str,
) -> Result<DiagnosticBuilder<'tcx>, ErrorHandled> {
self.struct_generic(tcx, message, None)
}
pub fn report_as_error(&self, tcx: TyCtxtAt<'tcx>, message: &str) -> ErrorHandled {
let err = self.struct_error(tcx, message);
match err {
Ok(mut err) => {
err.emit();
ErrorHandled::Reported
},
Err(err) => err,
}
}
pub fn report_as_lint(
&self,
tcx: TyCtxtAt<'tcx>,
message: &str,
lint_root: hir::HirId,
span: Option<Span>,
) -> ErrorHandled {
let lint = self.struct_generic(
tcx,
message,
Some(lint_root),
);
match lint {
Ok(mut lint) => {
if let Some(span) = span {
let primary_spans = lint.span.primary_spans().to_vec();
// point at the actual error as the primary span
lint.replace_span_with(span);
// point to the `const` statement as a secondary span
// they don't have any label
for sp in primary_spans {
if sp != span {
lint.span_label(sp, "");
}
}
}
lint.emit();
ErrorHandled::Reported
},
Err(err) => err,
}
}
fn struct_generic(
&self,
tcx: TyCtxtAt<'tcx>,
message: &str,
lint_root: Option<hir::HirId>,
) -> Result<DiagnosticBuilder<'tcx>, ErrorHandled> {
let must_error = match self.error {
err_inval!(Layout(LayoutError::Unknown(_))) |
err_inval!(TooGeneric) =>
return Err(ErrorHandled::TooGeneric),
err_inval!(TypeckError) =>
return Err(ErrorHandled::Reported),
err_inval!(Layout(LayoutError::SizeOverflow(_))) => true,
_ => false,
};
trace!("reporting const eval failure at {:?}", self.span);
let mut err = if let (Some(lint_root), false) = (lint_root, must_error) {
let hir_id = self.stacktrace
.iter()
.rev()
.filter_map(|frame| frame.lint_root)
.next()
.unwrap_or(lint_root);
tcx.struct_span_lint_hir(
crate::rustc::lint::builtin::CONST_ERR,
hir_id,
tcx.span,
message,
)
} else if must_error {
struct_error(tcx, &self.error.to_string())
} else {
struct_error(tcx, message)
};
if !must_error {
err.span_label(self.span, self.error.to_string());
}
// Skip the last, which is just the environment of the constant. The stacktrace
// is sometimes empty because we create "fake" eval contexts in CTFE to do work
// on constant values.
if self.stacktrace.len() > 0 {
for frame_info in &self.stacktrace[..self.stacktrace.len()-1] {
err.span_label(frame_info.call_site, frame_info.to_string());
}
}
Ok(err)
}
}
pub fn struct_error<'tcx>(tcx: TyCtxtAt<'tcx>, msg: &str) -> DiagnosticBuilder<'tcx> {
struct_span_err!(tcx.sess, tcx.span, E0080, "{}", msg)
}
/// Packages the kind of error we got from the const code interpreter
/// up with a Rust-level backtrace of where the error occurred.
/// Thsese should always be constructed by calling `.into()` on
/// a `InterpError`. In `librustc_mir::interpret`, we have `throw_err_*`
/// macros for this.
#[derive(Debug, Clone)]
pub struct InterpErrorInfo<'tcx> {
pub kind: InterpError<'tcx>,
backtrace: Option<Box<Backtrace>>,
}
impl fmt::Display for InterpErrorInfo<'_> {
fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
write!(f, "{}", self.kind)
}
}
impl InterpErrorInfo<'_> {
pub fn print_backtrace(&mut self) {
if let Some(ref mut backtrace) = self.backtrace {
print_backtrace(&mut *backtrace);
}
}
}
fn print_backtrace(backtrace: &mut Backtrace) {
backtrace.resolve();
eprintln!("\n\nAn error occurred in miri:\n{:?}", backtrace);
}
impl From<ErrorHandled> for InterpErrorInfo<'tcx> {
fn from(err: ErrorHandled) -> Self {
match err {
ErrorHandled::Reported => err_inval!(ReferencedConstant),
ErrorHandled::TooGeneric => err_inval!(TooGeneric),
}.into()
}
}
impl<'tcx> From<InterpError<'tcx>> for InterpErrorInfo<'tcx> {
fn from(kind: InterpError<'tcx>) -> Self {
let backtrace = match env::var("RUSTC_CTFE_BACKTRACE") {
// Matching `RUST_BACKTRACE` -- we treat "0" the same as "not present".
Ok(ref val) if val != "0" => {
let mut backtrace = Backtrace::new_unresolved();
if val == "immediate" {
// Print it now.
print_backtrace(&mut backtrace);
None
} else {
Some(Box::new(backtrace))
}
},
_ => None,
};
InterpErrorInfo {
kind,
backtrace,
}
}
}
#[derive(Clone, RustcEncodable, RustcDecodable, HashStable, PartialEq)]
pub enum PanicInfo<O> {
Panic {
msg: Symbol,
line: u32,
col: u32,
file: Symbol,
},
BoundsCheck {
len: O,
index: O,
},
Overflow(mir::BinOp),
OverflowNeg,
DivisionByZero,
RemainderByZero,
ResumedAfterReturn(GeneratorKind),
ResumedAfterPanic(GeneratorKind),
}
/// Type for MIR `Assert` terminator error messages.
pub type AssertMessage<'tcx> = PanicInfo<mir::Operand<'tcx>>;
impl<O> PanicInfo<O> {
/// Getting a description does not require `O` to be printable, and does not
/// require allocation.
/// The caller is expected to handle `Panic` and `BoundsCheck` separately.
pub fn description(&self) -> &'static str {
use PanicInfo::*;
match self {
Overflow(mir::BinOp::Add) =>
"attempt to add with overflow",
Overflow(mir::BinOp::Sub) =>
"attempt to subtract with overflow",
Overflow(mir::BinOp::Mul) =>
"attempt to multiply with overflow",
Overflow(mir::BinOp::Div) =>
"attempt to divide with overflow",
Overflow(mir::BinOp::Rem) =>
"attempt to calculate the remainder with overflow",
OverflowNeg =>
"attempt to negate with overflow",
Overflow(mir::BinOp::Shr) =>
"attempt to shift right with overflow",
Overflow(mir::BinOp::Shl) =>
"attempt to shift left with overflow",
Overflow(op) =>
bug!("{:?} cannot overflow", op),
DivisionByZero =>
"attempt to divide by zero",
RemainderByZero =>
"attempt to calculate the remainder with a divisor of zero",
ResumedAfterReturn(GeneratorKind::Gen) =>
"generator resumed after completion",
ResumedAfterReturn(GeneratorKind::Async(_)) =>
"`async fn` resumed after completion",
ResumedAfterPanic(GeneratorKind::Gen) =>
"generator resumed after panicking",
ResumedAfterPanic(GeneratorKind::Async(_)) =>
"`async fn` resumed after panicking",
Panic { .. } | BoundsCheck { .. } =>
bug!("Unexpected PanicInfo"),
}
}
}
impl<O: fmt::Debug> fmt::Debug for PanicInfo<O> {
fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
use PanicInfo::*;
match self {
Panic { ref msg, line, col, ref file } =>
write!(f, "the evaluated program panicked at '{}', {}:{}:{}", msg, file, line, col),
BoundsCheck { ref len, ref index } =>
write!(f, "index out of bounds: the len is {:?} but the index is {:?}", len, index),
_ =>
write!(f, "{}", self.description()),
}
}
}
/// Error information for when the program we executed turned out not to actually be a valid
/// program. This cannot happen in stand-alone Miri, but it can happen during CTFE/ConstProp
/// where we work on generic code or execution does not have all information available.
#[derive(Clone, HashStable)]
pub enum InvalidProgramInfo<'tcx> {
/// Resolution can fail if we are in a too generic context.
TooGeneric,
/// Cannot compute this constant because it depends on another one
/// which already produced an error.
ReferencedConstant,
/// Abort in case type errors are reached.
TypeckError,
/// An error occurred during layout computation.
Layout(layout::LayoutError<'tcx>),
}
impl fmt::Debug for InvalidProgramInfo<'tcx> {
fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
use InvalidProgramInfo::*;
match self {
TooGeneric =>
write!(f, "encountered overly generic constant"),
ReferencedConstant =>
write!(f, "referenced constant has errors"),
TypeckError =>
write!(f, "encountered constants with type errors, stopping evaluation"),
Layout(ref err) =>
write!(f, "{}", err),
}
}
}
/// Error information for when the program caused Undefined Behavior.
#[derive(Clone, HashStable)]
pub enum UndefinedBehaviorInfo {
/// Free-form case. Only for errors that are never caught!
Ub(String),
/// Free-form case for experimental UB. Only for errors that are never caught!
UbExperimental(String),
/// Unreachable code was executed.
Unreachable,
/// An enum discriminant was set to a value which was outside the range of valid values.
InvalidDiscriminant(ScalarMaybeUndef),
/// A slice/array index projection went out-of-bounds.
BoundsCheckFailed { len: u64, index: u64 },
/// Something was divided by 0 (x / 0).
DivisionByZero,
/// Something was "remainded" by 0 (x % 0).
RemainderByZero,
/// Overflowing inbounds pointer arithmetic.
PointerArithOverflow,
}
impl fmt::Debug for UndefinedBehaviorInfo {
fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
use UndefinedBehaviorInfo::*;
match self {
Ub(msg) | UbExperimental(msg) =>
write!(f, "{}", msg),
Unreachable =>
write!(f, "entering unreachable code"),
InvalidDiscriminant(val) =>
write!(f, "encountering invalid enum discriminant {}", val),
BoundsCheckFailed { ref len, ref index } =>
write!(f, "indexing out of bounds: the len is {:?} but the index is {:?}",
len, index),
DivisionByZero =>
write!(f, "dividing by zero"),
RemainderByZero =>
write!(f, "calculating the remainder with a divisor of zero"),
PointerArithOverflow =>
write!(f, "overflowing in-bounds pointer arithmetic"),
}
}
}
/// Error information for when the program did something that might (or might not) be correct
/// to do according to the Rust spec, but due to limitations in the interpreter, the
/// operation could not be carried out. These limitations can differ between CTFE and the
/// Miri engine, e.g., CTFE does not support casting pointers to "real" integers.
///
/// Currently, we also use this as fall-back error kind for errors that have not been
/// categorized yet.
#[derive(Clone, HashStable)]
pub enum UnsupportedOpInfo<'tcx> {
/// Free-form case. Only for errors that are never caught!
Unsupported(String),
/// When const-prop encounters a situation it does not support, it raises this error.
/// This must not allocate for performance reasons.
ConstPropUnsupported(&'tcx str),
// -- Everything below is not categorized yet --
FunctionAbiMismatch(Abi, Abi),
FunctionArgMismatch(Ty<'tcx>, Ty<'tcx>),
FunctionRetMismatch(Ty<'tcx>, Ty<'tcx>),
FunctionArgCountMismatch,
UnterminatedCString(Pointer),
DanglingPointerDeref,
DoubleFree,
InvalidMemoryAccess,
InvalidFunctionPointer,
InvalidBool,
PointerOutOfBounds {
ptr: Pointer,
msg: CheckInAllocMsg,
allocation_size: Size,
},
InvalidNullPointerUsage,
ReadPointerAsBytes,
ReadBytesAsPointer,
ReadForeignStatic,
InvalidPointerMath,
ReadUndefBytes(Size),
DeadLocal,
InvalidBoolOp(mir::BinOp),
UnimplementedTraitSelection,
CalledClosureAsFunction,
NoMirFor(String),
DerefFunctionPointer,
ExecuteMemory,
InvalidChar(u128),
OutOfTls,
TlsOutOfBounds,
AlignmentCheckFailed {
required: Align,
has: Align,
},
ValidationFailure(String),
VtableForArgumentlessMethod,
ModifiedConstantMemory,
ModifiedStatic,
TypeNotPrimitive(Ty<'tcx>),
ReallocatedWrongMemoryKind(String, String),
DeallocatedWrongMemoryKind(String, String),
ReallocateNonBasePtr,
DeallocateNonBasePtr,
IncorrectAllocationInformation(Size, Size, Align, Align),
HeapAllocZeroBytes,
HeapAllocNonPowerOfTwoAlignment(u64),
ReadFromReturnPointer,
PathNotFound(Vec<String>),
}
impl fmt::Debug for UnsupportedOpInfo<'tcx> {
fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
use UnsupportedOpInfo::*;
match self {
PointerOutOfBounds { ptr, msg, allocation_size } => {
write!(f, "{} failed: pointer must be in-bounds at offset {}, \
but is outside bounds of allocation {} which has size {}",
msg, ptr.offset.bytes(), ptr.alloc_id, allocation_size.bytes())
},
ValidationFailure(ref err) => {
write!(f, "type validation failed: {}", err)
}
NoMirFor(ref func) => write!(f, "no MIR for `{}`", func),
FunctionAbiMismatch(caller_abi, callee_abi) =>
write!(f, "tried to call a function with ABI {:?} using caller ABI {:?}",
callee_abi, caller_abi),
FunctionArgMismatch(caller_ty, callee_ty) =>
write!(f, "tried to call a function with argument of type {:?} \
passing data of type {:?}",
callee_ty, caller_ty),
FunctionRetMismatch(caller_ty, callee_ty) =>
write!(f, "tried to call a function with return type {:?} \
passing return place of type {:?}",
callee_ty, caller_ty),
FunctionArgCountMismatch =>
write!(f, "tried to call a function with incorrect number of arguments"),
ReallocatedWrongMemoryKind(ref old, ref new) =>
write!(f, "tried to reallocate memory from `{}` to `{}`", old, new),
DeallocatedWrongMemoryKind(ref old, ref new) =>
write!(f, "tried to deallocate `{}` memory but gave `{}` as the kind", old, new),
InvalidChar(c) =>
write!(f, "tried to interpret an invalid 32-bit value as a char: {}", c),
AlignmentCheckFailed { required, has } =>
write!(f, "tried to access memory with alignment {}, but alignment {} is required",
has.bytes(), required.bytes()),
TypeNotPrimitive(ty) =>
write!(f, "expected primitive type, got {}", ty),
PathNotFound(ref path) =>
write!(f, "cannot find path {:?}", path),
IncorrectAllocationInformation(size, size2, align, align2) =>
write!(f, "incorrect alloc info: expected size {} and align {}, \
got size {} and align {}",
size.bytes(), align.bytes(), size2.bytes(), align2.bytes()),
InvalidMemoryAccess =>
write!(f, "tried to access memory through an invalid pointer"),
DanglingPointerDeref =>
write!(f, "dangling pointer was dereferenced"),
DoubleFree =>
write!(f, "tried to deallocate dangling pointer"),
InvalidFunctionPointer =>
write!(f, "tried to use a function pointer after offsetting it"),
InvalidBool =>
write!(f, "invalid boolean value read"),
InvalidNullPointerUsage =>
write!(f, "invalid use of NULL pointer"),
ReadPointerAsBytes =>
write!(f, "a raw memory access tried to access part of a pointer value as raw \
bytes"),
ReadBytesAsPointer =>
write!(f, "a memory access tried to interpret some bytes as a pointer"),
ReadForeignStatic =>
write!(f, "tried to read from foreign (extern) static"),
InvalidPointerMath =>
write!(f, "attempted to do invalid arithmetic on pointers that would leak base \
addresses, e.g., comparing pointers into different allocations"),
DeadLocal =>
write!(f, "tried to access a dead local variable"),
DerefFunctionPointer =>
write!(f, "tried to dereference a function pointer"),
ExecuteMemory =>
write!(f, "tried to treat a memory pointer as a function pointer"),
OutOfTls =>
write!(f, "reached the maximum number of representable TLS keys"),
TlsOutOfBounds =>
write!(f, "accessed an invalid (unallocated) TLS key"),
CalledClosureAsFunction =>
write!(f, "tried to call a closure through a function pointer"),
VtableForArgumentlessMethod =>
write!(f, "tried to call a vtable function without arguments"),
ModifiedConstantMemory =>
write!(f, "tried to modify constant memory"),
ModifiedStatic =>
write!(f, "tried to modify a static's initial value from another static's \
initializer"),
ReallocateNonBasePtr =>
write!(f, "tried to reallocate with a pointer not to the beginning of an \
existing object"),
DeallocateNonBasePtr =>
write!(f, "tried to deallocate with a pointer not to the beginning of an \
existing object"),
HeapAllocZeroBytes =>
write!(f, "tried to re-, de- or allocate zero bytes on the heap"),
ReadFromReturnPointer =>
write!(f, "tried to read from the return pointer"),
UnimplementedTraitSelection =>
write!(f, "there were unresolved type arguments during trait selection"),
InvalidBoolOp(_) =>
write!(f, "invalid boolean operation"),
UnterminatedCString(_) =>
write!(f, "attempted to get length of a null-terminated string, but no null \
found before end of allocation"),
ReadUndefBytes(_) =>
write!(f, "attempted to read undefined bytes"),
HeapAllocNonPowerOfTwoAlignment(_) =>
write!(f, "tried to re-, de-, or allocate heap memory with alignment that is \
not a power of two"),
Unsupported(ref msg) =>
write!(f, "{}", msg),
ConstPropUnsupported(ref msg) =>
write!(f, "Constant propagation encountered an unsupported situation: {}", msg),
}
}
}
/// Error information for when the program exhausted the resources granted to it
/// by the interpreter.
#[derive(Clone, HashStable)]
pub enum ResourceExhaustionInfo {
/// The stack grew too big.
StackFrameLimitReached,
/// The program ran into an infinite loop.
InfiniteLoop,
}
impl fmt::Debug for ResourceExhaustionInfo {
fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
use ResourceExhaustionInfo::*;
match self {
StackFrameLimitReached =>
write!(f, "reached the configured maximum number of stack frames"),
InfiniteLoop =>
write!(f, "duplicate interpreter state observed here, const evaluation will never \
terminate"),
}
}
}
#[derive(Clone, HashStable)]
pub enum InterpError<'tcx> {
/// The program panicked.
Panic(PanicInfo<u64>),
/// The program caused undefined behavior.
UndefinedBehavior(UndefinedBehaviorInfo),
/// The program did something the interpreter does not support (some of these *might* be UB
/// but the interpreter is not sure).
Unsupported(UnsupportedOpInfo<'tcx>),
/// The program was invalid (ill-typed, not sufficiently monomorphized, ...).
InvalidProgram(InvalidProgramInfo<'tcx>),
/// The program exhausted the interpreter's resources (stack/heap too big,
/// execution takes too long, ..).
ResourceExhaustion(ResourceExhaustionInfo),
/// Not actually an interpreter error -- used to signal that execution has exited
/// with the given status code. Used by Miri, but not by CTFE.
Exit(i32),
}
pub type InterpResult<'tcx, T = ()> = Result<T, InterpErrorInfo<'tcx>>;
impl fmt::Display for InterpError<'_> {
fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
// Forward `Display` to `Debug`.
write!(f, "{:?}", self)
}
}
impl fmt::Debug for InterpError<'_> {
fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
use InterpError::*;
match *self {
Unsupported(ref msg) =>
write!(f, "{:?}", msg),
InvalidProgram(ref msg) =>
write!(f, "{:?}", msg),
UndefinedBehavior(ref msg) =>
write!(f, "{:?}", msg),
ResourceExhaustion(ref msg) =>
write!(f, "{:?}", msg),
Panic(ref msg) =>
write!(f, "{:?}", msg),
Exit(code) =>
write!(f, "exited with status code {}", code),
}
}
}