1# Irtoc tool 2 3**Irtoc**(Ir-To-Code) tool is aimed to compile a manually created IR (intermediate representation) to the target code. 4 5Building flow: 6 7 8 9## Irtoc language 10 11> WARNING: this part is still under development. Thus, some things may be changed in the final implementation. 12 13Irtoc DSL is a wrapper above the `IrConstructor`. It reads compiler's `instructions.yaml` file to get information about instructions. As output it generates c++ code, that uses `IrConstructor` to build IR. 14 15Each opcode in the IR instructions has corresponding token in the irtoc lang. For example, IR instruction `Add`: 16``` 17 - opcode: Add 18 base: BinaryOperation 19 signature: [d-number, number, number] 20 flags: [commutative, acc_write, acc_read, ifcvt] 21 description: Add two inputs. 22``` 23has keyword with the same name `Add` and with same signature: 24``` 25var = Add(input1, input2) 26``` 27 28All property setters that IrConstructor provides (`i64`, `bool`, `Pc`, `CC`, etc) are 29available in Irtoc lang. They can be set in the similar way as in the IrConstructor: 30``` 31var = Add(input1, input2).i64.CC(:CC_GE).pc(123) 32``` 33### Pseudo instructions 34Pseudo instructions are not a real IR instructions in terms of compiler, those instructions are needed only as helpers 35for Irtoc. For example, for creating a control flow: Label, Else, While. 36 37Pseudo instructions are described like regular instructions in the `instructions.yaml` file, but in the separate section `pseudo_instructions`. 38 39### Data flow 40 41In last example variable `var` holds the newly created instruction `Add` and it can be input for the further instructions. 42Thus, dataflow is constructing like in other general-purpose language: assign variable - use variable: 43``` 44var = Add(input1, input2).i64.CC(:CC_GE).pc(123) 45Return(var).i64 46``` 47Also it is possible to omit variables and create instruction in-place: 48``` 49Return(Add(input1, input2).i64.CC(:CC_GE).pc(123)).i64 50``` 51 52### Control flow 53 54Irtoc uses instruction `If` and pseudo instruction `Else` to express conditional execution. 55 56For example, add 1 to the biggest value: 57``` 58function TestIncMaxValue(params: {a: i64, b: i64}) { 59 If(a, b).CC(:CC_GE) { 60 v1 = Add(a, 1).i64 61 } Else { 62 v2 = Add(b, 1).i64 63 } 64 phi = Phi(v1, v2) 65 Return(phi).i64 66} 67``` 68 69After automatic phi insertion will be implemented: 70``` 71function TestIncMaxValue(params: {a: i64, b: i64}) { 72 If(a, b).CC(:CC_GE) { 73 v = Add(a, 1).i64 74 } Else { 75 v = Add(b, 1).i64 76 } 77 Return(v).i64 78} 79``` 80 81`While` statement has the following semantic: 82``` 83function SumSequence(params: {start: u64, end: u64}) { 84 res = 0 85 While (start, end).cc(ne) { 86 res = Add(res, start) 87 start = Add(start, 1) 88 } 89 90 Return.u32(res) 91} 92``` 93 94Using labels: 95 96``` 97function SumSequence(params: {start: u64, end: u64}) { 98 res = 0 99 100 Label(head) 101 If (start, end).cc(ne) { 102 Goto(exit) 103 } 104 105 res = Add(res, start) 106 start = Add(start, 1) 107 Goto(head) 108 109 Label(exit) 110 111 Return.u32(res) 112} 113``` 114 115## Dedicated registers 116 117Sometimes there will be need to specify target register for the input parameter or other entities within a script. 118 119For such needs, each function takes registers map as an input: 120``` 121regmap_tls = {ARM64: {tr: 28}, 122 ARM32: {tr: 12}, 123 X86_64: {tr: 15}} 124function CallEntrypoint(params: {offset: u64, tls: ptr(tr)}, regmap=regmap_tls) { 125 entry = Load(tr, offset) 126 Call(entry) 127} 128``` 129It will be transformed to the folloiwng code for Arm64 target: 130``` 131COMPILE(CallEntrypoint) { 132 GRAPH(GetGraph()) { 133 PARAMETER(0, 1).u64(); 134 PARAMETER(1, 1).ptr().DstReg(28); // for x86 will be `.DstReg(15)` 135 ... 136 } 137} 138``` 139So, 28 register will be reserved for the life interval started by the second parameter. 140
