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2021-11-15Stage2: wasm - Implement the MIR pass (#10153)Luuk de Gram
* wasm: Move wasm's codegen to arch/wasm/CodeGen.zig * wasm: Define Wasm's Mir This declares the initial most-used instructions for wasm as well as the data that represents them. TODO: Add binary operand opcodes. By re-using the wasm opcode values, we can emit each opcode very easily by simply using `@enumToInt()`. However, this poses a possible problem: If we use all of wasm's opcodes, it leaves us no room to use synthetic opcodes such as debugging instructions. We could use reserved opcodes, but the wasm spec may use them at some point. TODO: Check if we should perhaps use a 16bit tag where the highest bits are used for synthetic opcodes. * wasm: Define basic Emit structure * wasm: Implement corresponding Emit functions for MIR * wasm: Initial lowering to MIR - This implements lowering to MIR from AIR for storing and loading of locals as well as emitting immediates. - Relocating function indexes has been simplified a lot as well as we no longer need to patch offsets and we write a relocatable value instead. - Locals are now emitted at the beginning of the function section entry meaning all offsets we generate are stable. * wasm: Lower all AIR instructions to MIR * wasm: Implement remaining MIR instructions * wasm: Fix function relocations * wasm: Get all tests working * wasm: Make `Data` 4 bytes instead of 8. - 64bit immediates are now stored in 2 seperate u32's. - 64bit floats are now stored in 2 seperate u32's. - `mem_arg` is now stored as a seperate payload in extra.
2021-11-09Sema: implement coerce_result_ptr for optionalsAndrew Kelley
New AIR instruction: `optional_payload_ptr_set` It's like `optional_payload_ptr` except it sets the non-null bit. When storing to the payload via a result location that is an optional, `optional_payload_ptr_set` is now emitted. There is a new algorithm in `zirCoerceResultPtr` which stores a dummy value through the result pointer into a temporary block, and then pops off the AIR instructions from the temporary block in order to determine how to transform the result location pointer in case any in-between coercions need to happen. Fixes a couple of behavior tests regarding optionals.
2021-10-26stage2: implement runtime pointer access to global constantsAndrew Kelley
The main problem that motivated these changes is that global constants which are referenced by pointer would not be emitted into the binary. This happened because `semaDecl` did not add `codegen_decl` tasks for global constants, instead relying on the constant values being copied as necessary. However when the global constants are referenced by pointer, they need to be sent to the linker to be emitted. After making global const arrays, structs, and unions get emitted, this uncovered a latent issue: the anonymous decls that they referenced would get garbage collected (via `deleteUnusedDecl`) even though they would later be referenced by the global const. In order to solve this problem, I introduced `anon_work_queue` which is the same as `work_queue` except a lower priority. The `codegen_decl` task for anon decls goes into the `anon_work_queue` ensuring that the owner decl gets a chance to mark its anon decls as alive before they are possibly deleted. This caused a few regressions, which I made the judgement call to add workarounds for. Two steps forward, one step back, is still progress. The regressions were: * Two behavior tests having to do with unions. These tests were intentionally exercising the LLVM constant value lowering, however, due to the bug with garbage collection that was fixed in this commit, the LLVM code was not getting exercised, and union types/values were not implemented correctly, due to me forgetting that LLVM does not allow bitcasting aggregate values. - This is worked around by allowing those 2 test cases to regress, moving them to the "passing for stage1 only" section. * The test-stage2 test cases (in test/cases/*) for non-LLVM backends previously did not have any calls to lower struct values, but now they do. The code that was there was just `@panic("TODO")`. I replaced that code with a stub that generates the wrong value. This is an intentional miscompilation that will obviously need to get fixed before any struct behavior tests pass. None of the current tests we have exercise loading any values from these global const structs, so there is not a problem until we try to improve these backends.
2021-10-21stage2: more division supportAndrew Kelley
AIR: * div is renamed to div_trunc. * Add div_float, div_floor, div_exact. - Implemented in Sema and LLVM codegen. C backend has a stub. Improvements to std.math.big.Int: * Add `eqZero` function to `Mutable`. * Fix incorrect results for `divFloor`. Compiler-rt: * Add muloti4 to the stage2 section.
2021-10-19stage2: wasm: implement struct_field_valAndrew Kelley
2021-10-02Delete Module.Scope, move Block into SemaMartin Wickham
2021-09-24Spelling corrections (#9833)Josh Soref
Signed-off-by: Josh Soref <jsoref@users.noreply.github.com> Co-authored-by: Josh Soref <jsoref@users.noreply.github.com>
2021-08-21stage2 Air: add struct_field_ptr_index_{0..3}Jacob G-W
Since these are very common, it will save memory.
2021-08-21stage2: comptime function with the same args is memoizedAndrew Kelley
* Introduce `memoized_calls` to `Module` which stores all the comptime function calls that are cached. It is keyed on the `*Fn` and the comptime arguments, but it does not yet properly detect comptime function pointers and avoid memoizing in this case. So it will have false positives for when a comptime function call mutates data through a pointer parameter. * Sema: Add a new helper function: `resolveConstMaybeUndefVal` * Value: add `enumToInt` method and use it in `zirEnumToInt`. It is also used by the hashing function. * Value: fix representation of optionals to match error unions. Previously it would not handle nested optionals correctly. Now it matches the memory layout of error unions and supports nested optionals properly. This required changes in all the backends for generating optional constants. * TypedValue gains `eql` and `hash` methods. * Value: Implement hashing for floats, optionals, and enums. Additionally, the zig type tag is added to the hash, where it was not previously, so that values of differing types will get different hashes.
2021-08-07stage2: pass some error union testsAndrew Kelley
* Value: rename `error_union` to `eu_payload` and clarify the intended usage in the doc comments. The way error unions is represented with Value is fixed to not have ambiguous values. * Fix codegen for error union constants in all the backends. * Implement the AIR instructions having to do with error unions in the LLVM backend.
2021-08-01wasm: Resolve feedback (wrapping arbitrary int sizes)Luuk de Gram
- This ensures we honor the user's integer size when performing wrapping operations. - Also, instead of using ensureCapacity, we now use ensureUnusedCapacity.
2021-08-01wasm: Implement optionalsLuuk de Gram
This uses the same approach as error unions, meaning it's a `WValue` with its tag set to `multi_value`. The initial index of the multi_value will contain the null-tag, used to check if the value is null or not. The other values will be the payload. To support the `.?` shorthand syntax, we save the result from checking the null-tag into a new local, which can then be loaded later in the block to either hit `unreachable` or set the actual payload value. Currently, it seems `.?` and `orelse unreachable` results in different AIR structure. TODO: Is this expected?
2021-08-01wasm: Implement wrapping operands, add opcodes to wasm.zigLuuk de Gram
- Some opcodes have the incorrect value set in std. - Some opcodes were missing and have now been added to std. - Adding wrapping operands for add,sub and mul. - Implement intCast which either extends or shortens the type.
2021-07-29stage2: garbage collect unused anon declsAndrew Kelley
After this change, the frontend and backend cooperate to keep track of which Decls are actually emitted into the machine code. When any backend sees a `decl_ref` Value, it must mark the corresponding Decl `alive` field to true. This prevents unused comptime data from spilling into the output object files. For example, if you do an `inline for` loop, previously, any intermediate value calculations would have gone into the object file. Now they are garbage collected immediately after the owner Decl has its machine code generated. In the frontend, when it is time to send a Decl to the linker, if it has not been marked "alive" then it is deleted instead. Additional improvements: * Resolve type ABI layouts after successful semantic analysis of a Decl. This is needed so that the backend has access to struct fields. * Sema: fix incorrect logic in resolveMaybeUndefVal. It should return "not comptime known" instead of a compile error for global variables. * `Value.pointerDeref` now returns `null` in the case that the pointer deref cannot happen at compile-time. This is true for global variables, for example. Another example is if a comptime known pointer has a hard coded address value. * Binary arithmetic sets the requireRuntimeBlock source location to the lhs_src or rhs_src as appropriate instead of on the operator node. * Fix LLVM codegen for slice_elem_val which had the wrong logic for when the operand was not a pointer. As noted in the comment in the implementation of deleteUnusedDecl, a future improvement will be to rework the frontend/linker interface to remove the frontend's responsibility of calling allocateDeclIndexes. I discovered some issues with the plan9 linker backend that are related to this, and worked around them for now.
2021-07-29stage2: more principled approach to comptime referencesAndrew Kelley
* AIR no longer has a `variables` array. Instead of the `varptr` instruction, Sema emits a constant with a `decl_ref`. * AIR no longer has a `ref` instruction. There is no longer any instruction that takes a value and returns a pointer to it. If this is desired, Sema must either create an anynomous Decl and return a constant `decl_ref`, or in the case of a runtime value, emit an `alloc` instruction, `store` the value to it, and then return the `alloc`. * The `ref_val` Value Tag is eliminated. `decl_ref` should be used instead. Also added is `eu_payload_ptr` which points to the payload of an error union, given an error union pointer. In general, Sema should avoid calling `analyzeRef` if it can be helped. For example in the case of field_val and elem_val, there should never be a reason to create a temporary (alloc or decl). Recent previous commits made progress along that front. There is a new abstraction in Sema, which looks like this: var anon_decl = try block.startAnonDecl(); defer anon_decl.deinit(); // here 'anon_decl.arena()` may be used const decl = try anon_decl.finish(ty, val); // decl is typically now used with `decl_ref`. This pattern is used to upgrade `ref_val` usages to `decl_ref` usages. Additional improvements: * Sema: fix source location resolution for calling convention expression. * Sema: properly report "unable to resolve comptime value" for loads of global variables. There is now a set of functions which can be called if the callee wants to obtain the Value even if the tag is `variable` (indicating comptime-known address but runtime-known value). * Sema: `coerce` resolves builtin types before checking equality. * Sema: fix `u1_type` missing from `addType`, making this type have a slightly more efficient representation in AIR. * LLVM backend: fix `genTypedValue` for tags `decl_ref` and `variable` to properly do an LLVMConstBitCast. * Remove unused parameter from `Value.toEnum`. After this commit, some test cases are no longer passing. This is due to the more principled approach to comptime references causing more anonymous decls to get sent to the linker for codegen. However, in all these cases the decls are not actually referenced by the runtime machine code. A future commit in this branch will implement garbage collection of decls so that unused decls do not get sent to the linker for codegen. This will make the tests go back to passing.
2021-07-26stage2: improvements towards `zig test`Andrew Kelley
* Add AIR instruction: struct_field_val - This is part of an effort to eliminate the AIR instruction `ref`. - It's implemented for C backend and LLVM backend so far. * Rename `resolvePossiblyUndefinedValue` to `resolveMaybeUndefVal` just to save some columns on long lines. * Sema: add `fieldVal` alongside `fieldPtr` (renamed from `namedFieldPtr`). This is part of an effort to eliminate the AIR instruction `ref`. The idea is to avoid unnecessary loads, stores, stack usage, and IR instructions, by paying a DRY cost. LLVM backend improvements: * internal linkage vs exported linkage is implemented, along with aliases. There is an issue with incremental updates due to missing LLVM API for deleting aliases; see the relevant comment in this commit. - `updateDeclExports` is hooked up to the LLVM backend now. * Fix usage of `Type.tag() == .noreturn` rather than calling `isNoReturn()`. * Properly mark global variables as mutable/constant. * Fix llvm type generation of function pointers * Fix codegen for calls of function pointers * Implement llvm type generation of error unions and error sets. * Implement AIR instructions: addwrap, subwrap, mul, mulwrap, div, bit_and, bool_and, bit_or, bool_or, xor, struct_field_ptr, struct_field_val, unwrap_errunion_err, add for floats, sub for floats. After this commit, `zig test` on a file with `test "example" {}` correctly generates and executes a test binary. However the `test_functions` slice is undefined and just happens to be going into the .bss section, causing the length to be 0. The next step towards `zig test` will be replacing the `test_functions` Decl Value with the set of test function pointers, before it is sent to linker/codegen.
2021-07-24Re-enable switch test cases and fix regressionsLuuk de Gram
2021-07-24Support multi-value prongsLuuk de Gram
2021-07-24Allow negative valuesLuuk de Gram
2021-07-24switchbr: When prongs are sparse values, use if/else-chainLuuk de Gram
2021-07-24wasm: Rewrite switch_br to use `br_table` insteadLuuk de Gram
This is an initial version, todo: - Also make this work for u64 values, as the table must be indexed by u32. - Add support for signed integers. - Add support for enums.
2021-07-23stage2: improvements towards `zig test`Andrew Kelley
* There is now a main_pkg in addition to root_pkg. They are usually the same. When using `zig test`, main_pkg is the user's source file and root_pkg has the test runner. * scanDecl no longer looks for test decls outside the package being tested. honoring `--test-filter` is still TODO. * test runner main function has a void return value rather than `anyerror!void` * Sema is improved to generate better AIR for for loops on slices. * Sema: fix incorrect capacity calculation in zirBoolBr * Sema: add compile errors for trying to use slice fields as an lvalue. * Sema: fix type coercion for error unions * Sema: fix analyzeVarRef generating garbage AIR * C codegen: fix renderValue for error unions with 0 bit payload * C codegen: implement function pointer calls * CLI: fix usage text Adds 4 new AIR instructions: * slice_len, slice_ptr: to get the ptr and len fields of a slice. * slice_elem_val, ptr_slice_elem_val: to get the element value of a slice, and a pointer to a slice. AstGen gains a new functionality: * One of the unused flags of struct decls is now used to indicate structs that are known to have non-zero size based on the AST alone.
2021-07-20Sema: reimplement runtime switchAndrew Kelley
Now supports multiple items pointing to the same body. This is a common pattern even when using a jump table, with multiple cases pointing to the same block of code. In the case of a range specified, the items are moved to branches in the else body. A future improvement may make it possible to have jump table items as well as ranges pointing to the same block of code.
2021-07-20Resolve regressionsLuuk de Gram
- Get correct types in wasm backend. - `arg` is already a `Ref`, therefore simply use `@intToEnum`. - Fix regression in `zirBoolBr, where the order of insertion was incorrect.
2021-07-20wasm: Resolve regressions, add intcast supportLuuk de Gram
2021-07-20stage2: wasm backend: update to latest naming conventionAndrew Kelley
2021-07-20stage2: update LLVM backend to new AIR memory layoutAndrew Kelley
Also fix compile errors when not using -Dskip-non-native
2021-07-20Refactor entire wasm-backend to use new AIR memory layoutLuuk de Gram
2021-07-20Fix wasm-related compile errors:Luuk de Gram
- Update `fail()` to not require a `srcLoc`. This brings it in line with other backends, and we were always passing 'node_offset = 0', anyway. - Fix unused local due to change of architecture wrt function/decl generation. - Replace all old instructions to indexes within the function signatures.
2021-07-20stage2: Air and Liveness are passed ephemerallyAndrew Kelley
to the link infrastructure, instead of being stored with Module.Fn. This moves towards a strategy to make more efficient use of memory by not storing Air or Liveness data in the Fn struct, but computing it on demand, immediately sending it to the backend, and then immediately freeing it. Backends which want to defer codegen until flush() such as SPIR-V must move the Air/Liveness data upon `updateFunc` being called and keep track of that data in the backend implementation itself.
2021-07-20stage2: rework AIR memory layoutAndrew Kelley
This commit changes the AIR file and the documentation of the memory layout. The actual work of modifying the surrounding code (in Sema and codegen) is not yet done.
2021-07-07stage2: fix if expressions on error unionsAndrew Kelley
AstGen had the then-else logic backwards for if expressions on error unions. This commit fixes it. Turns out AstGen only really needs `is_non_null` and `is_non_err`, and does not need the `is_null` or `is_err` variants. So I removed the `is_null{,_ptr}` and `is_err{,_ptr}` ZIR instructions (-4) and added `is_non_err`, `is_non_err_ptr` ZIR instructions (+2) for a total of (-2) ZIR instructions, giving us a tiny bit more headroom within the 256 tag limit. This required swapping the order of then/else blocks in a handful of cases, but ultimately means the ZIR will be in the same as source order, which is convenient when debugging. AIR code on the other hand, gains the `is_non_err` and `is_non_err_ptr` instructions. Sema: fix logic in zirErrUnionCode and zirErrUnionCodePtr returning the wrong result type.
2021-06-21cleanups related to unused paramsAndrew Kelley
2021-06-21fix code broken from previous commitJacob G-W
2021-06-21std, src, doc, test: remove unused variablesJacob G-W
2021-06-03Breaking hash map changes for 0.8.0Martin Wickham
- hash/eql functions moved into a Context object - *Context functions pass an explicit context - *Adapted functions pass specialized keys and contexts - new getPtr() function returns a pointer to value - remove functions renamed to fetchRemove - new remove functions return bool - removeAssertDiscard deleted, use assert(remove(...)) instead - Keys and values are stored in separate arrays - Entry is now {*K, *V}, the new KV is {K, V} - BufSet/BufMap functions renamed to match other set/map types - fixed iterating-while-modifying bug in src/link/C.zig
2021-05-28wasm: Add stage2 tests for error unionsLuuk de Gram
2021-05-28wasm: Reverse the order of error and payloadLuuk de Gram
This will set us up to correctly retrieve the error local index and payload index depending on that of the multi_value's index. As from now, the error will always use the multi_value's index, and the payload will use the following locals.
2021-05-28wasm: Add support for error union as return typeLuuk de Gram
- This currently uses the multi-value feature to return both the possible error, and its payload. - Also genAlloc and the logic to allocate the locals itself have been seperated, so we can create more locals whenever needed, and not only when `genAlloc` is called.
2021-05-28wasm: Implement error unions and unwrappingLuuk de Gram
- Slightly refactored `Wvalue.multi_value` to also contain the amount of locals it contains, this allows us to set all fields at once.
2021-05-28wasm: Support error setsLuuk de Gram
2021-05-22stage2: Move BlockData out of ir.Inst.Blockjoachimschmidt557
2021-05-22stage2: rename ir.zig to air.zigAndrew Kelley
We've settled on the nomenclature for the artifacts the compiler pipeline produces: 1. Tokens 2. AST (Abstract Syntax Tree) 3. ZIR (Zig Intermediate Representation) 4. AIR (Analyzed Intermediate Representation) 5. Machine Code Renaming `ir` identifiers to `air` will come with the inevitable air-memory-layout branch that I plan to start after the 0.8.0 release.
2021-05-20Also support multi-prong branchesLuuk de Gram
2021-05-20stage2 wasm: Support basic switchesLuuk de Gram
- Adds support for single branches - Allows both enums and integers - Supports 'else' branch
2021-05-20wasm backend: implement `multi_value` for `WValue`Luuk de Gram
This allows us to differentiate between regular locals and variables that create multiple locals on the stack such as optionals and structs. Now `struct_a = struct_b;` works and only updates a reference, rather than update all local's values. Also created more test cases to test against this.
2021-05-19Do not create a local for the struct itself + test casesLuuk de Gram
2021-05-19Initial support for structs in wasm backendLuuk de Gram
- Creates a 'local' for the struct itself and each field - The index of the local is calculated from the struct's local index + field index
2021-05-19Explicit return & more complex wasm enum testLuuk de Gram
- When returning within a block, we must use an explicit return opcode. For now always emit the opcode when calling return, rather than using implicit return statements. - Also added a more comprehensive test case to test for enum values using conditions
2021-05-19wasm backend - Initial enum supportLuuk de Gram
- This adds support for enum values using field indexes - EmitConstant's signature was changed so it's easier to recursively call it using a different type (enum -> int type). - Implemented initial support for bitcast which for now just returns the `WValue` of the operand.