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| 1 | +use rustc_target::abi::Size; |
| 2 | + |
| 3 | +use crate::*; |
| 4 | + |
| 5 | +// Locks are pointer-sized pieces of data, initialized to 0. |
| 6 | +// We use them to count readers, with usize::MAX representing the write-locked state. |
| 7 | + |
| 8 | +fn deref_lock<'mir, 'tcx: 'mir>( |
| 9 | + ecx: &mut MiriEvalContext<'mir, 'tcx>, |
| 10 | + lock_op: OpTy<'tcx, Tag>, |
| 11 | +) -> InterpResult<'tcx, MPlaceTy<'tcx, Tag>> { |
| 12 | + // `lock` is a pointer to `void*`; cast it to a pointer to `usize`. |
| 13 | + let lock = ecx.deref_operand(lock_op)?; |
| 14 | + let usize = ecx.machine.layouts.usize; |
| 15 | + assert_eq!(lock.layout.size, usize.size); |
| 16 | + Ok(lock.offset(Size::ZERO, MemPlaceMeta::None, usize, ecx)?) |
| 17 | +} |
| 18 | + |
| 19 | +impl<'mir, 'tcx> EvalContextExt<'mir, 'tcx> for crate::MiriEvalContext<'mir, 'tcx> {} |
| 20 | +pub trait EvalContextExt<'mir, 'tcx: 'mir>: crate::MiriEvalContextExt<'mir, 'tcx> { |
| 21 | + #[allow(non_snake_case)] |
| 22 | + fn AcquireSRWLockExclusive( |
| 23 | + &mut self, |
| 24 | + lock_op: OpTy<'tcx, Tag>, |
| 25 | + ) -> InterpResult<'tcx> { |
| 26 | + let this = self.eval_context_mut(); |
| 27 | + assert_eq!(this.get_total_thread_count(), 1, "concurrency on Windows is not supported"); |
| 28 | + |
| 29 | + let lock = deref_lock(this, lock_op)?; |
| 30 | + let lock_val = this.read_scalar(lock.into())?.to_machine_usize(this)?; |
| 31 | + if lock_val == 0 { |
| 32 | + // Currently not locked. Lock it. |
| 33 | + let new_val = Scalar::from_machine_usize(this.machine_usize_max(), this); |
| 34 | + this.write_scalar(new_val, lock.into())?; |
| 35 | + } else { |
| 36 | + // Lock is already held. This is a deadlock. |
| 37 | + throw_machine_stop!(TerminationInfo::Deadlock); |
| 38 | + } |
| 39 | + |
| 40 | + Ok(()) |
| 41 | + } |
| 42 | + |
| 43 | + #[allow(non_snake_case)] |
| 44 | + fn TryAcquireSRWLockExclusive( |
| 45 | + &mut self, |
| 46 | + lock_op: OpTy<'tcx, Tag>, |
| 47 | + ) -> InterpResult<'tcx, u8> { |
| 48 | + let this = self.eval_context_mut(); |
| 49 | + assert_eq!(this.get_total_thread_count(), 1, "concurrency on Windows is not supported"); |
| 50 | + |
| 51 | + let lock = deref_lock(this, lock_op)?; |
| 52 | + let lock_val = this.read_scalar(lock.into())?.to_machine_usize(this)?; |
| 53 | + if lock_val == 0 { |
| 54 | + // Currently not locked. Lock it. |
| 55 | + let new_val = this.machine_usize_max(); |
| 56 | + this.write_scalar(Scalar::from_machine_usize(new_val, this), lock.into())?; |
| 57 | + Ok(1) |
| 58 | + } else { |
| 59 | + // Lock is already held. |
| 60 | + Ok(0) |
| 61 | + } |
| 62 | + } |
| 63 | + |
| 64 | + #[allow(non_snake_case)] |
| 65 | + fn ReleaseSRWLockExclusive( |
| 66 | + &mut self, |
| 67 | + lock_op: OpTy<'tcx, Tag>, |
| 68 | + ) -> InterpResult<'tcx> { |
| 69 | + let this = self.eval_context_mut(); |
| 70 | + assert_eq!(this.get_total_thread_count(), 1, "concurrency on Windows is not supported"); |
| 71 | + |
| 72 | + let lock = deref_lock(this, lock_op)?; |
| 73 | + let lock_val = this.read_scalar(lock.into())?.to_machine_usize(this)?; |
| 74 | + if lock_val == this.machine_usize_max() { |
| 75 | + // Currently locked. Unlock it. |
| 76 | + let new_val = 0; |
| 77 | + this.write_scalar(Scalar::from_machine_usize(new_val, this), lock.into())?; |
| 78 | + } else { |
| 79 | + // Lock is not locked. |
| 80 | + throw_ub_format!("calling ReleaseSRWLockExclusive on an SRWLock that is not exclusively locked"); |
| 81 | + } |
| 82 | + |
| 83 | + Ok(()) |
| 84 | + } |
| 85 | + |
| 86 | + #[allow(non_snake_case)] |
| 87 | + fn AcquireSRWLockShared( |
| 88 | + &mut self, |
| 89 | + lock_op: OpTy<'tcx, Tag>, |
| 90 | + ) -> InterpResult<'tcx> { |
| 91 | + let this = self.eval_context_mut(); |
| 92 | + assert_eq!(this.get_total_thread_count(), 1, "concurrency on Windows is not supported"); |
| 93 | + |
| 94 | + let lock = deref_lock(this, lock_op)?; |
| 95 | + let lock_val = this.read_scalar(lock.into())?.to_machine_usize(this)?; |
| 96 | + if lock_val == this.machine_usize_max() { |
| 97 | + // Currently write locked. This is a deadlock. |
| 98 | + throw_machine_stop!(TerminationInfo::Deadlock); |
| 99 | + } else { |
| 100 | + // Bump up read counter (cannot overflow as we just checkd against usize::MAX); |
| 101 | + let new_val = lock_val+1; |
| 102 | + // Make sure this does not reach the "write locked" flag. |
| 103 | + if new_val == this.machine_usize_max() { |
| 104 | + throw_unsup_format!("SRWLock read-acquired too many times"); |
| 105 | + } |
| 106 | + this.write_scalar(Scalar::from_machine_usize(new_val, this), lock.into())?; |
| 107 | + } |
| 108 | + |
| 109 | + Ok(()) |
| 110 | + } |
| 111 | + |
| 112 | + #[allow(non_snake_case)] |
| 113 | + fn TryAcquireSRWLockShared( |
| 114 | + &mut self, |
| 115 | + lock_op: OpTy<'tcx, Tag>, |
| 116 | + ) -> InterpResult<'tcx, u8> { |
| 117 | + let this = self.eval_context_mut(); |
| 118 | + assert_eq!(this.get_total_thread_count(), 1, "concurrency on Windows is not supported"); |
| 119 | + |
| 120 | + let lock = deref_lock(this, lock_op)?; |
| 121 | + let lock_val = this.read_scalar(lock.into())?.to_machine_usize(this)?; |
| 122 | + if lock_val == this.machine_usize_max() { |
| 123 | + // Currently write locked. |
| 124 | + Ok(0) |
| 125 | + } else { |
| 126 | + // Bump up read counter (cannot overflow as we just checkd against usize::MAX); |
| 127 | + let new_val = lock_val+1; |
| 128 | + // Make sure this does not reach the "write locked" flag. |
| 129 | + if new_val == this.machine_usize_max() { |
| 130 | + throw_unsup_format!("SRWLock read-acquired too many times"); |
| 131 | + } |
| 132 | + this.write_scalar(Scalar::from_machine_usize(new_val, this), lock.into())?; |
| 133 | + Ok(1) |
| 134 | + } |
| 135 | + } |
| 136 | + |
| 137 | + #[allow(non_snake_case)] |
| 138 | + fn ReleaseSRWLockShared( |
| 139 | + &mut self, |
| 140 | + lock_op: OpTy<'tcx, Tag>, |
| 141 | + ) -> InterpResult<'tcx> { |
| 142 | + let this = self.eval_context_mut(); |
| 143 | + assert_eq!(this.get_total_thread_count(), 1, "concurrency on Windows is not supported"); |
| 144 | + |
| 145 | + let lock = deref_lock(this, lock_op)?; |
| 146 | + let lock_val = this.read_scalar(lock.into())?.to_machine_usize(this)?; |
| 147 | + if lock_val == this.machine_usize_max() { |
| 148 | + // Currently write locked. This is a UB. |
| 149 | + throw_ub_format!("calling ReleaseSRWLockShared on write-locked SRWLock"); |
| 150 | + } else if lock_val == 0 { |
| 151 | + // Currently not locked at all. |
| 152 | + throw_ub_format!("calling ReleaseSRWLockShared on unlocked SRWLock"); |
| 153 | + } else { |
| 154 | + // Decrement read counter (cannot overflow as we just checkd against 0); |
| 155 | + let new_val = lock_val-1; |
| 156 | + this.write_scalar(Scalar::from_machine_usize(new_val, this), lock.into())?; |
| 157 | + } |
| 158 | + |
| 159 | + Ok(()) |
| 160 | + } |
| 161 | +} |
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