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2019-04-09SMT: Refactor Jib values to make inlining workAlasdair Armstrong
Had to change the hundreds and hundreds of places such values were used. However this now lets us automatically prove cheri-concentrate properties. Such as showing function prop_cap_round_trip(cap: bits(128)) -> bool = { let cap_rt = capToBits(capBitsToCapability(true, cap)); cap == cap_rt } is always true.
2019-04-06Various bugfixes and improvementsAlasdair
- Rename DeIid to Operator. It corresponds to operator <string> in the syntax. The previous name is from when it was called deinfix in sail1. - Removed things that weren't actually common from pretty_print_common.ml, e.g. printing identifiers is backend specific. The doc_id function here was only used for a very specific use case in pretty_print_lem, so I simplified it and renamed it to doc_sia_id, as it is always used for a SIA.Id whatever that is. - There is some support for anonymous records in constructors, e.g. union Foo ('a : Type) = { MkFoo : { field1 : 'a, field2 : int } } somewhat similar to the enum syntax in Rust. I'm not sure when this was added, but there were a few odd things about it. It was desugared in the preprocessor, rather than initial_check, and the desugaring generated incorrect code for polymorphic anonymous records as above. I moved the code to initial_check, so the pre-processor now just deals with pre-processor things and not generating types, and I fixed the code to work with polymorphic types. This revealed some issues in the C backend w.r.t. polymorphic structs, which is the bulk of this commit. I also added some tests for this feature. - OCaml backend can now generate a valid string_of function for polymorphic structs, previously this would cause the ocaml to fail to compile. - Some cleanup in the Sail ott definition - Add support for E_var in interpreter previously this would just cause the interpreter to fail
2019-04-01C: Add identifier to end instructionAlasdair
Allows us to track the last version of the return variable when the AST in in SSA form.
2019-03-27C: Generate C from sliced specificationsAlasdair Armstrong
2019-03-19C: Some simplificationAlasdair Armstrong
Remove unused experimental optimizations
2019-03-15C: Wrap Jib identifiersAlasdair
Avoids duplication between l-expressions and expressions. Also means that special variables like current_exception and have_exception are treated normally by functions such as instr_reads and instr_writes etc. Furthermore we can now easily annotate Jib identifiers in ways that were not previously possible with plain sail ids.
2019-03-13C: Improve Jib IR, add SSA representationAlasdair Armstrong
Add a CL_void l-expression so we don't have redundant unit-typed variables everywhere, and add an optimization in Jib_optimize called optimize_unit which introduces these. Remove the basic control-flow graph in Jib_util and add a new mutable control-flow graph type in Jib_ssa which allows the IR to be converted into SSA form. The mutable graph allows for more efficient updates, and includes both back and forwards references making it much more convenient to traverse. Having an SSA representation should make some optimizations much simpler, and is also probably more natural for SMT generation where variables have to be defined once using declare-const anyway. Debug option -ddump_flow_graphs now outputs SSA'd graphs of the functions in a specification.
2019-03-08Rewriter: Cleanup old sizeof rewritesAlasdair Armstrong
Shouldn't affect anything as this is done by the typechecker now. Also remove some unfinished tracing code from c_backend.ml
2019-03-08C: Refactor C backendAlasdair Armstrong
Main change is splitting apart the Sail->IR compilation stage and the C code generation and optimization phase. Rather than variously calling the intermediate language either bytecode (when it's not really) or simply IR, we give it a name: Jib (a type of Sail). Most of the types are still prefixed by c/C, and I don't think it's worth changing this. The various parts of the C backend are now in the src/jib/ subdirectory src/jib/anf.ml - Sail->ANF translation src/jib/jib_util.ml - various Jib AST processing and helper functions (formerly bytecode_util) src/jib/jib_compile.ml - Sail->Jib translation (using Sail->ANF) src/jib/c_backend.ml - Jib->C code generator and optimizations Further, bytecode.ott is now jib.ott and generates jib.ml (which still lives in src/ for now) The optimizations in c_backend.ml should eventually be moved in a separate jib_optimization file. The Sail->Jib compilation can be parameterised by two functions - one is a custom ANF->ANF optimization pass that can be specified on a per Jib backend basis, and the other is the rule for translating Sail types in Jib types. This can be more or less precise depending on how precise we want to be about bit-widths etc, i.e. we only care about <64 and >64 for C, but for SMT generation we would want to be as precise as possible. Additional improvements: The Jib IR is now agnostic about whether arguments are allocated on the heap vs the stack and this is handled by the C code generator. jib.ott now has some more comments explaining various parts of the Jib AST. A Set module and comparison function for ctyps is defined, and some functions now return ctyp sets rather than lists to avoid repeated work.