diff options
Diffstat (limited to 'yjit/src')
-rw-r--r-- | yjit/src/core.rs | 115 |
1 files changed, 95 insertions, 20 deletions
diff --git a/yjit/src/core.rs b/yjit/src/core.rs index 75585d67a0..0ec5a0adca 100644 --- a/yjit/src/core.rs +++ b/yjit/src/core.rs @@ -461,15 +461,20 @@ pub struct Context { /// ([Self::is_return_landing]) chain_depth_return_landing: u8, + // Type we track for self + self_type: Type, + // Local variable types we keep track of // We store 8 local types, requiring 4 bits each, for a total of 32 bits local_types: u32, - // Type we track for self - self_type: Type, + // Temp mapping kinds we track + // 8 temp mappings * 2 bits, total 16 bits + temp_mapping_kind: u16, - // Mapping of temp stack entries to types we track - temp_mapping: [TempMapping; MAX_TEMP_TYPES], + // Stack slot type/local_idx we track + // 8 temp types * 4 bits, total 32 bits + temp_payload: u32, } /// Tuple of (iseq, idx) used to identify basic blocks @@ -1698,7 +1703,7 @@ impl Context { return Type::Unknown; } - let mapping = self.temp_mapping[stack_idx]; + let mapping = self.get_temp_mapping(stack_idx); match mapping.get_kind() { MapToSelf => self.self_type, @@ -1724,6 +1729,75 @@ impl Context { } } + /// Get the current temp mapping for a given stack slot + fn get_temp_mapping(&self, temp_idx: usize) -> TempMapping { + assert!(temp_idx < MAX_TEMP_TYPES); + + // Extract the temp mapping kind + let kind_bits = (self.temp_mapping_kind >> (2 * temp_idx)) & 0b11; + let temp_kind = unsafe { transmute::<u8, TempMappingKind>(kind_bits as u8) }; + + // Extract the payload bits (temp type or local idx) + let payload_bits = (self.temp_payload >> (4 * temp_idx)) & 0b1111; + + match temp_kind { + MapToSelf => TempMapping::map_to_self(), + + MapToStack => { + TempMapping::map_to_stack( + unsafe { transmute::<u8, Type>(payload_bits as u8) } + ) + } + + MapToLocal => { + TempMapping::map_to_local( + payload_bits as u8 + ) + } + } + } + + /// Get the current temp mapping for a given stack slot + fn set_temp_mapping(&mut self, temp_idx: usize, mapping: TempMapping) { + assert!(temp_idx < MAX_TEMP_TYPES); + + // Extract the kind bits + let mapping_kind = mapping.get_kind(); + let kind_bits = unsafe { transmute::<TempMappingKind, u8>(mapping_kind) }; + assert!(kind_bits <= 0b11); + + // Extract the payload bits + let payload_bits = match mapping_kind { + MapToSelf => 0, + + MapToStack => { + let t = mapping.get_type(); + unsafe { transmute::<Type, u8>(t) } + } + + MapToLocal => { + mapping.get_local_idx() + } + }; + assert!(payload_bits <= 0b1111); + + // Update the kind bits + { + let mask_bits = 0b11_u16 << (2 * temp_idx); + let shifted_bits = (kind_bits as u16) << (2 * temp_idx); + let all_kind_bits = self.temp_mapping_kind as u16; + self.temp_mapping_kind = (all_kind_bits & !mask_bits) | shifted_bits; + } + + // Update the payload bits + { + let mask_bits = 0b1111_u32 << (4 * temp_idx); + let shifted_bits = (payload_bits as u32) << (4 * temp_idx); + let all_payload_bits = self.temp_payload as u32; + self.temp_payload = (all_payload_bits & !mask_bits) | shifted_bits; + } + } + /// Upgrade (or "learn") the type of an instruction operand /// This value must be compatible and at least as specific as the previously known type. /// If this value originated from self, or an lvar, the learned type will be @@ -1745,14 +1819,14 @@ impl Context { return; } - let mapping = self.temp_mapping[stack_idx]; + let mapping = self.get_temp_mapping(stack_idx); match mapping.get_kind() { MapToSelf => self.self_type.upgrade(opnd_type), MapToStack => { let mut temp_type = mapping.get_type(); temp_type.upgrade(opnd_type); - self.temp_mapping[stack_idx] = TempMapping::map_to_stack(temp_type); + self.set_temp_mapping(stack_idx, TempMapping::map_to_stack(temp_type)); } MapToLocal => { let idx = mapping.get_local_idx() as usize; @@ -1781,7 +1855,7 @@ impl Context { let stack_idx = (self.stack_size - 1 - idx) as usize; if stack_idx < MAX_TEMP_TYPES { - self.temp_mapping[stack_idx] + self.get_temp_mapping(stack_idx) } else { // We can't know the source of this stack operand, so we assume it is // a stack-only temporary. type will be UNKNOWN @@ -1810,7 +1884,7 @@ impl Context { return; } - self.temp_mapping[stack_idx] = mapping; + self.set_temp_mapping(stack_idx, mapping); } } } @@ -1827,9 +1901,9 @@ impl Context { } // If any values on the stack map to this local we must detach them - for mapping_idx in 0..self.temp_mapping.len() { - let mapping = self.temp_mapping[mapping_idx]; - self.temp_mapping[mapping_idx] = match mapping.get_kind() { + for mapping_idx in 0..MAX_TEMP_TYPES { + let mapping = self.get_temp_mapping(mapping_idx); + let tm = match mapping.get_kind() { MapToStack => mapping, MapToSelf => mapping, MapToLocal => { @@ -1841,7 +1915,8 @@ impl Context { TempMapping::map_to_local(idx) } } - } + }; + self.set_temp_mapping(mapping_idx, tm); } // Update the type bits @@ -1858,11 +1933,11 @@ impl Context { // When clearing local types we must detach any stack mappings to those // locals. Even if local values may have changed, stack values will not. - for mapping_idx in 0..self.temp_mapping.len() { - let mapping = self.temp_mapping[mapping_idx]; + for mapping_idx in 0..MAX_TEMP_TYPES { + let mapping = self.get_temp_mapping(mapping_idx); if mapping.get_kind() == MapToLocal { let local_idx = mapping.get_local_idx() as usize; - self.temp_mapping[mapping_idx] = TempMapping::map_to_stack(self.get_local_type(local_idx)); + self.set_temp_mapping(mapping_idx, TempMapping::map_to_stack(self.get_local_type(local_idx))); } } @@ -1979,7 +2054,7 @@ impl Assembler { // Keep track of the type and mapping of the value if stack_size < MAX_TEMP_TYPES { - self.ctx.temp_mapping[stack_size] = mapping; + self.ctx.set_temp_mapping(stack_size, mapping); if mapping.get_kind() == MapToLocal { let idx = mapping.get_local_idx(); @@ -2030,7 +2105,7 @@ impl Assembler { let idx: usize = (self.ctx.stack_size as usize) - i - 1; if idx < MAX_TEMP_TYPES { - self.ctx.temp_mapping[idx] = TempMapping::map_to_stack(Type::Unknown); + self.ctx.set_temp_mapping(idx, TempMapping::map_to_stack(Type::Unknown)); } } @@ -2048,7 +2123,7 @@ impl Assembler { for i in method_name_index..(self.ctx.stack_size - 1) as usize { if i + 1 < MAX_TEMP_TYPES { - self.ctx.temp_mapping[i] = self.ctx.temp_mapping[i + 1]; + self.ctx.set_temp_mapping(i, self.ctx.get_temp_mapping(i + 1)); } } self.stack_pop(1); @@ -3297,7 +3372,7 @@ mod tests { #[test] fn context_size() { - assert_eq!(mem::size_of::<Context>(), 17); + assert_eq!(mem::size_of::<Context>(), 15); } #[test] |