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docs/rosette: More intro of SMT-LIB backend 

As the intro paragraph (now) says:
> This section will introduce the SMT-LIB functional backend and what changes are needed...

The example is intended to be read without prior knowledge of the SMT-LIB backend, but the previous version glossed over a lot and instead focused on *just* what was changed.
This version should now be easier to follow without prior knowledge, while still being able to learn enough about the `Smt` version to adapt it to a different s-expression target that isn't Rosette.
Also adds a few `literalinclude`s of smtlib.cc, which is now copied to `docs/source/generated` along with producing the rosette diff on the fly (which now also has up to 20 lines of context, enabling the full `Module::write()` diff to be literal included).
This commit is contained in:
Krystine Sherwin 2025-02-22 17:14:13 +13:00
parent 819c3260ec
commit c429aef60f
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3 changed files with 98 additions and 437 deletions
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14
Makefile
View File

@ -996,6 +996,18 @@ docs/source/cell/word_add.rst: $(TARGETS) $(EXTRA_TARGETS)
docs/source/generated/cells.json: docs/source/generated $(TARGETS) $(EXTRA_TARGETS)
$(Q) ./$(PROGRAM_PREFIX)yosys -p 'help -dump-cells-json $@'
docs/source/generated/%.cc: backends/%.cc
$(Q) mkdir -p $(@D)
$(Q) cp $< $@
# diff returns exit code 1 if the files are different, but it's not an error
docs/source/generated/functional/rosette.diff: backends/functional/smtlib.cc backends/functional/smtlib_rosette.cc
$(Q) mkdir -p $(@D)
$(Q) diff -U 20 $^ > $@ || exit 0
PHONY: docs/gen/functional_ir
docs/gen/functional_ir: docs/source/generated/functional/smtlib.cc docs/source/generated/functional/rosette.diff
PHONY: docs/gen docs/usage docs/reqs
docs/gen: $(TARGETS)
$(Q) $(MAKE) -C docs gen
@ -1031,7 +1043,7 @@ docs/reqs:
$(Q) $(MAKE) -C docs reqs
.PHONY: docs/prep
docs/prep: docs/source/cmd/abc.rst docs/source/generated/cells.json docs/gen docs/usage
docs/prep: docs/source/cmd/abc.rst docs/source/generated/cells.json docs/gen docs/usage docs/gen/functional_ir
DOC_TARGET ?= html
docs: docs/prep

372
docs/source/code_examples/functional/rosette.diff
View File

@ -1,372 +0,0 @@
diff --git a/backends/functional/smtlib.cc b/backends/functional/smtlib_rosette.cc
index 3eacf407c..c9e737d19 100644
--- a/backends/functional/smtlib.cc
+++ b/backends/functional/smtlib_rosette.cc
@@ -29,80 +29,86 @@ PRIVATE_NAMESPACE_BEGIN
using SExprUtil::list;
const char *reserved_keywords[] = {
- // reserved keywords from the smtlib spec
- "BINARY", "DECIMAL", "HEXADECIMAL", "NUMERAL", "STRING", "_", "!", "as", "let", "exists", "forall", "match", "par",
- "assert", "check-sat", "check-sat-assuming", "declare-const", "declare-datatype", "declare-datatypes",
- "declare-fun", "declare-sort", "define-fun", "define-fun-rec", "define-funs-rec", "define-sort",
- "exit", "get-assertions", "symbol", "sort", "get-assignment", "get-info", "get-model",
- "get-option", "get-proof", "get-unsat-assumptions", "get-unsat-core", "get-value",
- "pop", "push", "reset", "reset-assertions", "set-info", "set-logic", "set-option",
+ // reserved keywords from the racket spec
+ "struct", "lambda", "values", "extract", "concat", "bv", "let", "define", "cons", "list", "read", "write",
+ "stream", "error", "raise", "exit", "for", "begin", "when", "unless", "module", "require", "provide", "apply",
+ "if", "cond", "even", "odd", "any", "and", "or", "match", "command-line", "ffi-lib", "thread", "kill", "sync",
+ "future", "touch", "subprocess", "make-custodian", "custodian-shutdown-all", "current-custodian", "make", "tcp",
+ "connect", "prepare", "malloc", "free", "_fun", "_cprocedure", "build", "path", "file", "peek", "bytes",
+ "flush", "with", "lexer", "parser", "syntax", "interface", "send", "make-object", "new", "instantiate",
+ "define-generics", "set",
// reserved for our own purposes
- "pair", "Pair", "first", "second",
- "inputs", "state",
+ "inputs", "state", "name",
nullptr
};
-struct SmtScope : public Functional::Scope<int> {
- SmtScope() {
+struct SmtrScope : public Functional::Scope<int> {
+ SmtrScope() {
for(const char **p = reserved_keywords; *p != nullptr; p++)
reserve(*p);
}
bool is_character_legal(char c, int index) override {
- return isascii(c) && (isalpha(c) || (isdigit(c) && index > 0) || strchr("~!@$%^&*_-+=<>.?/", c));
+ return isascii(c) && (isalpha(c) || (isdigit(c) && index > 0) || strchr("@$%^&_+=.", c));
}
};
-struct SmtSort {
+struct SmtrSort {
Functional::Sort sort;
- SmtSort(Functional::Sort sort) : sort(sort) {}
+ SmtrSort(Functional::Sort sort) : sort(sort) {}
SExpr to_sexpr() const {
if(sort.is_memory()) {
- return list("Array", list("_", "BitVec", sort.addr_width()), list("_", "BitVec", sort.data_width()));
+ return list("list", list("bitvector", sort.addr_width()), list("bitvector", sort.data_width()));
} else if(sort.is_signal()) {
- return list("_", "BitVec", sort.width());
+ return list("bitvector", sort.width());
} else {
log_error("unknown sort");
}
}
};
-class SmtStruct {
+class SmtrStruct {
struct Field {
- SmtSort sort;
+ SmtrSort sort;
std::string accessor;
+ std::string name;
};
idict<IdString> field_names;
vector<Field> fields;
- SmtScope &scope;
+ SmtrScope &global_scope;
+ SmtrScope local_scope;
public:
std::string name;
- SmtStruct(std::string name, SmtScope &scope) : scope(scope), name(name) {}
- void insert(IdString field_name, SmtSort sort) {
+ SmtrStruct(std::string name, SmtrScope &scope) : global_scope(scope), local_scope(), name(name) {}
+ void insert(IdString field_name, SmtrSort sort) {
field_names(field_name);
- auto accessor = scope.unique_name("\\" + name + "_" + RTLIL::unescape_id(field_name));
- fields.emplace_back(Field{sort, accessor});
+ auto base_name = local_scope.unique_name(field_name);
+ auto accessor = name + "-" + base_name;
+ global_scope.reserve(accessor);
+ fields.emplace_back(Field{sort, accessor, base_name});
}
void write_definition(SExprWriter &w) {
- w.open(list("declare-datatype", name));
- w.open(list());
- w.open(list(name));
- for(const auto &field : fields)
- w << list(field.accessor, field.sort.to_sexpr());
- w.close(3);
+ vector<SExpr> field_list;
+ for(const auto &field : fields) {
+ field_list.emplace_back(field.name);
+ }
+ w.push();
+ w.open(list("struct", name, field_list, "#:transparent"));
+ if (field_names.size()) {
+ for (const auto &field : fields) {
+ auto bv_type = field.sort.to_sexpr();
+ w.comment(field.name + " " + bv_type.to_string());
+ }
+ }
+ w.pop();
}
template<typename Fn> void write_value(SExprWriter &w, Fn fn) {
- if(field_names.empty()) {
- // Zero-argument constructors in SMTLIB must not be called as functions.
- w << name;
- } else {
- w.open(list(name));
- for(auto field_name : field_names) {
- w << fn(field_name);
- w.comment(RTLIL::unescape_id(field_name), true);
- }
- w.close();
+ w.open(list(name));
+ for(auto field_name : field_names) {
+ w << fn(field_name);
+ w.comment(RTLIL::unescape_id(field_name), true);
}
+ w.close();
}
SExpr access(SExpr record, IdString name) {
size_t i = field_names.at(name);
@@ -117,28 +123,28 @@ std::string smt_const(RTLIL::Const const &c) {
return s;
}
-struct SmtPrintVisitor : public Functional::AbstractVisitor<SExpr> {
+struct SmtrPrintVisitor : public Functional::AbstractVisitor<SExpr> {
using Node = Functional::Node;
std::function<SExpr(Node)> n;
- SmtStruct &input_struct;
- SmtStruct &state_struct;
+ SmtrStruct &input_struct;
+ SmtrStruct &state_struct;
- SmtPrintVisitor(SmtStruct &input_struct, SmtStruct &state_struct) : input_struct(input_struct), state_struct(state_struct) {}
+ SmtrPrintVisitor(SmtrStruct &input_struct, SmtrStruct &state_struct) : input_struct(input_struct), state_struct(state_struct) {}
SExpr from_bool(SExpr &&arg) {
- return list("ite", std::move(arg), "#b1", "#b0");
+ return list("bool->bitvector", std::move(arg));
}
SExpr to_bool(SExpr &&arg) {
- return list("=", std::move(arg), "#b1");
+ return list("bitvector->bool", std::move(arg));
}
- SExpr extract(SExpr &&arg, int offset, int out_width = 1) {
- return list(list("_", "extract", offset + out_width - 1, offset), std::move(arg));
+ SExpr to_list(SExpr &&arg) {
+ return list("bitvector->bits", std::move(arg));
}
SExpr buf(Node, Node a) override { return n(a); }
- SExpr slice(Node, Node a, int offset, int out_width) override { return extract(n(a), offset, out_width); }
- SExpr zero_extend(Node, Node a, int out_width) override { return list(list("_", "zero_extend", out_width - a.width()), n(a)); }
- SExpr sign_extend(Node, Node a, int out_width) override { return list(list("_", "sign_extend", out_width - a.width()), n(a)); }
+ SExpr slice(Node, Node a, int offset, int out_width) override { return list("extract", offset + out_width - 1, offset, n(a)); }
+ SExpr zero_extend(Node, Node a, int out_width) override { return list("zero-extend", n(a), list("bitvector", out_width)); }
+ SExpr sign_extend(Node, Node a, int out_width) override { return list("sign-extend", n(a), list("bitvector", out_width)); }
SExpr concat(Node, Node a, Node b) override { return list("concat", n(b), n(a)); }
SExpr add(Node, Node a, Node b) override { return list("bvadd", n(a), n(b)); }
SExpr sub(Node, Node a, Node b) override { return list("bvsub", n(a), n(b)); }
@@ -150,16 +156,11 @@ struct SmtPrintVisitor : public Functional::AbstractVisitor<SExpr> {
SExpr bitwise_xor(Node, Node a, Node b) override { return list("bvxor", n(a), n(b)); }
SExpr bitwise_not(Node, Node a) override { return list("bvnot", n(a)); }
SExpr unary_minus(Node, Node a) override { return list("bvneg", n(a)); }
- SExpr reduce_and(Node, Node a) override { return from_bool(list("=", n(a), smt_const(RTLIL::Const(State::S1, a.width())))); }
- SExpr reduce_or(Node, Node a) override { return from_bool(list("distinct", n(a), smt_const(RTLIL::Const(State::S0, a.width())))); }
- SExpr reduce_xor(Node, Node a) override {
- vector<SExpr> s { "bvxor" };
- for(int i = 0; i < a.width(); i++)
- s.push_back(extract(n(a), i));
- return s;
- }
- SExpr equal(Node, Node a, Node b) override { return from_bool(list("=", n(a), n(b))); }
- SExpr not_equal(Node, Node a, Node b) override { return from_bool(list("distinct", n(a), n(b))); }
+ SExpr reduce_and(Node, Node a) override { return list("apply", "bvand", to_list(n(a))); }
+ SExpr reduce_or(Node, Node a) override { return list("apply", "bvor", to_list(n(a))); }
+ SExpr reduce_xor(Node, Node a) override { return list("apply", "bvxor", to_list(n(a))); }
+ SExpr equal(Node, Node a, Node b) override { return from_bool(list("bveq", n(a), n(b))); }
+ SExpr not_equal(Node, Node a, Node b) override { return from_bool(list("not", list("bveq", n(a), n(b)))); }
SExpr signed_greater_than(Node, Node a, Node b) override { return from_bool(list("bvsgt", n(a), n(b))); }
SExpr signed_greater_equal(Node, Node a, Node b) override { return from_bool(list("bvsge", n(a), n(b))); }
SExpr unsigned_greater_than(Node, Node a, Node b) override { return from_bool(list("bvugt", n(a), n(b))); }
@@ -167,32 +168,32 @@ struct SmtPrintVisitor : public Functional::AbstractVisitor<SExpr> {
SExpr extend(SExpr &&a, int in_width, int out_width) {
if(in_width < out_width)
- return list(list("_", "zero_extend", out_width - in_width), std::move(a));
+ return list("zero-extend", std::move(a), list("bitvector", out_width));
else
return std::move(a);
}
SExpr logical_shift_left(Node, Node a, Node b) override { return list("bvshl", n(a), extend(n(b), b.width(), a.width())); }
SExpr logical_shift_right(Node, Node a, Node b) override { return list("bvlshr", n(a), extend(n(b), b.width(), a.width())); }
SExpr arithmetic_shift_right(Node, Node a, Node b) override { return list("bvashr", n(a), extend(n(b), b.width(), a.width())); }
- SExpr mux(Node, Node a, Node b, Node s) override { return list("ite", to_bool(n(s)), n(b), n(a)); }
- SExpr constant(Node, RTLIL::Const const &value) override { return smt_const(value); }
- SExpr memory_read(Node, Node mem, Node addr) override { return list("select", n(mem), n(addr)); }
- SExpr memory_write(Node, Node mem, Node addr, Node data) override { return list("store", n(mem), n(addr), n(data)); }
+ SExpr mux(Node, Node a, Node b, Node s) override { return list("if", to_bool(n(s)), n(b), n(a)); }
+ SExpr constant(Node, RTLIL::Const const& value) override { return list("bv", smt_const(value), value.size()); }
+ SExpr memory_read(Node, Node mem, Node addr) override { return list("list-ref-bv", n(mem), n(addr)); }
+ SExpr memory_write(Node, Node mem, Node addr, Node data) override { return list("list-set-bv", n(mem), n(addr), n(data)); }
SExpr input(Node, IdString name, IdString kind) override { log_assert(kind == ID($input)); return input_struct.access("inputs", name); }
SExpr state(Node, IdString name, IdString kind) override { log_assert(kind == ID($state)); return state_struct.access("state", name); }
};
-struct SmtModule {
+struct SmtrModule {
Functional::IR ir;
- SmtScope scope;
+ SmtrScope scope;
std::string name;
- SmtStruct input_struct;
- SmtStruct output_struct;
- SmtStruct state_struct;
+ SmtrStruct input_struct;
+ SmtrStruct output_struct;
+ SmtrStruct state_struct;
- SmtModule(Module *module)
+ SmtrModule(Module *module)
: ir(Functional::IR::from_module(module))
, scope()
, name(scope.unique_name(module->name))
@@ -200,7 +201,7 @@ struct SmtModule {
, output_struct(scope.unique_name(module->name.str() + "_Outputs"), scope)
, state_struct(scope.unique_name(module->name.str() + "_State"), scope)
{
- scope.reserve(name + "-initial");
+ scope.reserve(name + "_initial");
for (auto input : ir.inputs())
input_struct.insert(input->name, input->sort);
for (auto output : ir.outputs())
@@ -212,14 +213,11 @@ struct SmtModule {
void write_eval(SExprWriter &w)
{
w.push();
- w.open(list("define-fun", name,
- list(list("inputs", input_struct.name),
- list("state", state_struct.name)),
- list("Pair", output_struct.name, state_struct.name)));
+ w.open(list("define", list(name, "inputs", "state")));
auto inlined = [&](Functional::Node n) {
return n.fn() == Functional::Fn::constant;
};
- SmtPrintVisitor visitor(input_struct, state_struct);
+ SmtrPrintVisitor visitor(input_struct, state_struct);
auto node_to_sexpr = [&](Functional::Node n) -> SExpr {
if(inlined(n))
return n.visit(visitor);
@@ -230,9 +228,9 @@ struct SmtModule {
for(auto n : ir)
if(!inlined(n)) {
w.open(list("let", list(list(node_to_sexpr(n), n.visit(visitor)))), false);
- w.comment(SmtSort(n.sort()).to_sexpr().to_string(), true);
+ w.comment(SmtrSort(n.sort()).to_sexpr().to_string(), true);
}
- w.open(list("pair"));
+ w.open(list("cons"));
output_struct.write_value(w, [&](IdString name) { return node_to_sexpr(ir.output(name).value()); });
state_struct.write_value(w, [&](IdString name) { return node_to_sexpr(ir.state(name).next_value()); });
w.pop();
@@ -240,19 +238,23 @@ struct SmtModule {
void write_initial(SExprWriter &w)
{
- std::string initial = name + "-initial";
- w << list("declare-const", initial, state_struct.name);
+ w.push();
+ auto initial = name + "_initial";
+ w.open(list("define", initial));
+ w.open(list(state_struct.name));
for (auto state : ir.states()) {
- if(state->sort.is_signal())
- w << list("assert", list("=", state_struct.access(initial, state->name), smt_const(state->initial_value_signal())));
- else if(state->sort.is_memory()) {
+ if (state->sort.is_signal())
+ w << list("bv", smt_const(state->initial_value_signal()), state->sort.width());
+ else if (state->sort.is_memory()) {
const auto &contents = state->initial_value_memory();
+ w.open(list("list"));
for(int i = 0; i < 1<<state->sort.addr_width(); i++) {
- auto addr = smt_const(RTLIL::Const(i, state->sort.addr_width()));
- w << list("assert", list("=", list("select", state_struct.access(initial, state->name), addr), smt_const(contents[i])));
+ w << list("bv", smt_const(contents[i]), state->sort.data_width());
}
+ w.close();
}
}
+ w.pop();
}
void write(std::ostream &out)
@@ -263,33 +265,53 @@ struct SmtModule {
output_struct.write_definition(w);
state_struct.write_definition(w);
- w << list("declare-datatypes",
- list(list("Pair", 2)),
- list(list("par", list("X", "Y"), list(list("pair", list("first", "X"), list("second", "Y"))))));
-
write_eval(w);
write_initial(w);
}
};
-struct FunctionalSmtBackend : public Backend {
- FunctionalSmtBackend() : Backend("functional_smt2", "Generate SMT-LIB from Functional IR") {}
+struct FunctionalSmtrBackend : public Backend {
+ FunctionalSmtrBackend() : Backend("functional_rosette", "Generate Rosette compatible Racket from Functional IR") {}
- void help() override { log("\nFunctional SMT Backend.\n\n"); }
+ void help() override {
+ // |---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|
+ log("\n");
+ log(" write_functional_rosette [options] [filename]\n");
+ log("\n");
+ log("Functional Rosette Backend.\n");
+ log("\n");
+ log(" -provides\n");
+ log(" include 'provide' statement(s) for loading output as a module\n");
+ log("\n");
+ }
void execute(std::ostream *&f, std::string filename, std::vector<std::string> args, RTLIL::Design *design) override
{
- log_header(design, "Executing Functional SMT Backend.\n");
+ auto provides = false;
+
+ log_header(design, "Executing Functional Rosette Backend.\n");
- size_t argidx = 1;
- extra_args(f, filename, args, argidx, design);
+ size_t argidx;
+ for (argidx = 1; argidx < args.size(); argidx++)
+ {
+ if (args[argidx] == "-provides")
+ provides = true;
+ else
+ break;
+ }
+ extra_args(f, filename, args, argidx);
+
+ *f << "#lang rosette/safe\n";
+ if (provides) {
+ *f << "(provide (all-defined-out))\n";
+ }
for (auto module : design->selected_modules()) {
log("Processing module `%s`.\n", module->name.c_str());
- SmtModule smt(module);
- smt.write(*f);
+ SmtrModule smtr(module);
+ smtr.write(*f);
}
}
-} FunctionalSmtBackend;
+} FunctionalSmtrBackend;
PRIVATE_NAMESPACE_END

149
docs/source/yosys_internals/extending_yosys/functional_ir.rst
View File

@ -147,9 +147,9 @@ S-expressions can be constructed with ``SExpr::list``, for example ``SExpr expr
Example: Adapting SMT-LIB backend for Rosette
---------------------------------------------
This section will walk through the process of adapting the SMT-LIB functional
backend (`write_functional_smt2`) to work with another s-expression target,
`Rosette`_ (`write_functional_rosette`).
This section will introduce the SMT-LIB functional backend
(`write_functional_smt2`) and what changes are needed to work with another
s-expression target, `Rosette`_ (`write_functional_rosette`).
.. _Rosette: http://emina.github.io/rosette/
@ -177,12 +177,19 @@ Scope
~~~~~
As described above, the ``Functional::Scope`` class is derived in order to avoid
collisions between identifiers in the generated output. We switch out ``Smt``
in the class name for ``Smtr`` for ``smtlib_rosette``; which will happen through
the rest of the code too. We also update the ``is_character_legal`` method to
reject ascii characters which are not allowed in Racket variable names.
collisions between identifiers in the generated output. In the SMT-LIB version
the ``SmtScope`` class implements ``Scope<int>``; provides a constructor that
iterates over a list of reserved keywords, calling ``reserve`` on each; and
defines the ``is_character_legal`` method to reject any characters which are not
allowed in SMT-LIB variable names to then be replaced with underscores in the
output.
.. literalinclude:: /code_examples/functional/rosette.diff
In the Rosette version we switch out ``Smt`` in the class name for ``Smtr`` to
mean ``smtlib_rosette``; this will happen through the rest of the code too. We
also update list of legal ascii characters in the ``is_character_legal`` method
to only those allowed in Racket variable names.
.. literalinclude:: /generated/functional/rosette.diff
:language: diff
:caption: diff of ``Scope`` class
:start-at: -struct SmtScope : public Functional::Scope<int> {
@ -218,13 +225,13 @@ and racket specifications to save on space in this document.
Sort
~~~~
The ``Sort`` class is a wrapper for the ``Functional::Sort`` class, providing
the additional functionality of mapping variable declarations to s-expressions
with the ``to_sexpr()`` method. The main change from ``SmtSort`` to
``SmtrSort`` is a syntactical one with signals represented as ``bitvector``\
s, and memories as ``list``\ s of signals.
Next up in `write_functional_smt2` we see the ``Sort`` class. This is a wrapper
for the ``Functional::Sort`` class, providing the additional functionality of
mapping variable declarations to s-expressions with the ``to_sexpr()`` method.
The main change from ``SmtSort`` to ``SmtrSort`` is a syntactical one with
signals represented as ``bitvector``\ s, and memories as ``list``\ s of signals.
.. literalinclude:: /code_examples/functional/rosette.diff
.. literalinclude:: /generated/functional/rosette.diff
:language: diff
:caption: diff of ``Sort`` wrapper
:start-at: SExpr to_sexpr() const {
@ -233,37 +240,56 @@ s, and memories as ``list``\ s of signals.
Struct
~~~~~~
The SMT-LIB backend uses a class, ``SmtStruct``, to help with describing the
input, output, and state data structs. Where each struct in the SMT-LIB output
is a new ``datatype`` with each element having its type declared using the
`Sort`_ above, in Rosette we use the native ``struct`` with each field only
being referred to by name. For ease of use, we include comments for each field
to indicate the expected type.
The ``Functional::IR`` class tracks the set of inputs, the set of outputs, and
the set of "state" variables. The SMT-LIB backend maps each of these sets into
its own ``SmtStruct``, with each variable getting a corresponding field in the
struct and a specified `Sort`_. `write_functional_smt2` then defines each of
these structs as a new ``datatype``, with each element being strongly-typed.
.. literalinclude:: /code_examples/functional/rosette.diff
In Rosette, rather than defining new datatypes for our structs, we use the
native ``struct``. We also only declare each field by name because Racket is
not as strongly-typed. For ease of use, we provide the expected type for each
field as comments.
.. literalinclude:: /generated/functional/rosette.diff
:language: diff
:caption: diff of ``write_definition`` method
:start-at: void write_definition
:end-before: template<typename Fn> void write_value
Struct fields in Rosette are accessed as ``<struct_name>-<field_name>``, where
field names only need to be unique within the struct, while accessors are unique
within the module. We thus modify the class constructor and ``insert`` method
to support this; providing one scope that is local to the struct
(``local_scope``) and one which is shared across the whole module
(``global_scope``).
Each field is added to the ``SmtStruct`` with the ``insert`` method, which also
reserves a unique name (or accessor) within the `Scope`_. These accessors
combine the struct name and field name and are globally unique, being used in
the ``access`` method for reading values from the input/current state.
.. literalinclude:: /code_examples/functional/rosette.diff
.. literalinclude:: /generated/functional/smtlib.cc
:language: c++
:caption: ``Struct::access()`` method
:start-at: SExpr access(
:end-before: };
In Rosette, struct fields are accessed as ``<struct_name>-<field_name>`` so
including the struct name in the field name would be redundant. For
`write_functional_rosette` we instead choose to make field names unique only
within the struct, while accessors are unique across the whole module. We thus
modify the class constructor and ``insert`` method to support this; providing
one scope that is local to the struct (``local_scope``) and one which is shared
across the whole module (``global_scope``), leaving the ``access`` method
unchanged.
.. literalinclude:: /generated/functional/rosette.diff
:language: diff
:caption: diff of struct constructor
:start-at: SmtStruct(std::string name, SmtScope &scope)
:end-before: void write_definition
For writing outputs/next state (the ``write_value`` method), the only change is
to remove the check for zero-argument constructors since this is not necessary
with Rosette ``struct``\ s.
Finally, ``SmtStruct`` also provides a ``write_value`` template method which
calls a provided function on each element in the struct. This is used later for
assigning values to the output/next state pair. The only change here is to
remove the check for zero-argument constructors since this is not necessary with
Rosette ``struct``\ s.
.. literalinclude:: /code_examples/functional/rosette.diff
.. literalinclude:: /generated/functional/rosette.diff
:language: diff
:caption: diff of ``write_value`` method
:start-at: template<typename Fn> void write_value
@ -273,11 +299,13 @@ PrintVisitor
~~~~~~~~~~~~
The ``PrintVisitor`` implements the abstract ``Functional::AbstractVisitor``
class for converting FunctionalIR functions into s-expressions, including
reading inputs/current state. For most functions, the Rosette output is very
similar to the corresponding SMT-LIB function with minor adjustments for syntax.
class, described above in `What is FunctionalIR`_, with a return type of
``SExpr``. This class converts FunctionalIR functions into s-expressions,
including reading inputs/current state with the ``access`` method from the
`Struct`_. For most functions, the Rosette output is very similar to the
corresponding SMT-LIB function with minor adjustments for syntax.
.. literalinclude:: /code_examples/functional/rosette.diff
.. literalinclude:: /generated/functional/rosette.diff
:language: diff
:caption: portion of ``Functional::AbstractVisitor`` implementation diff showing similarities
:start-at: SExpr logical_shift_left
@ -286,7 +314,7 @@ similar to the corresponding SMT-LIB function with minor adjustments for syntax.
However there are some differences in the two formats with regards to how
booleans are handled, with Rosette providing built-in functions for conversion.
.. literalinclude:: /code_examples/functional/rosette.diff
.. literalinclude:: /generated/functional/rosette.diff
:language: diff
:caption: portion of ``Functional::AbstractVisitor`` implementation diff showing differences
:start-at: SExpr from_bool
@ -295,14 +323,21 @@ booleans are handled, with Rosette providing built-in functions for conversion.
Module
~~~~~~
The ``Functional::IR`` is wrapped in the ``Module`` class, with the mapping from
RTLIL module to FunctionalIR happening in the constructor. Each of the three
structs; inputs, outputs, and state; are then created from the corresponding
lists in the IR. The only change here is rename the initial state to use ``_``
instead of ``-``, since the ``-`` in Rosette can be used to access struct
fields.
The ``Functional::IR`` is wrapped in the ``SmtModule`` class, with the mapping
from RTLIL module to FunctionalIR happening in the constructor. Each of the
three ``SmtStruct``\ s; inputs, outputs, and state; are created, with each value
in the corresponding lists in the IR being ``insert``\ ed.
.. literalinclude:: /code_examples/functional/rosette.diff
.. literalinclude:: /generated/functional/smtlib.cc
:language: c++
:caption: ``SmtModule`` constructor
:start-at: SmtModule(Module
:end-at: }
Since Racket uses the ``-`` to access struct fields, the ``SmtrModule`` instead
uses an underscore for the name of the initial state.
.. literalinclude:: /generated/functional/rosette.diff
:language: diff
:caption: diff of ``Module`` constructor
:start-at: scope.reserve(name
@ -316,25 +351,11 @@ current_state) -> (outputs, next_state)`` with ``write_eval``, and declaring the
initial state with ``write_initial``. The only change for the ``SmtrModule`` is
that the ``pair`` declaration isn't needed.
.. inlined diff to show the complete function
.. code-block:: diff
.. literalinclude:: /generated/functional/rosette.diff
:language: diff
:caption: diff of ``Module::write()`` method
void write(std::ostream &out)
{
SExprWriter w(out);
input_struct.write_definition(w);
output_struct.write_definition(w);
state_struct.write_definition(w);
- w << list("declare-datatypes",
- list(list("Pair", 2)),
- list(list("par", list("X", "Y"), list(list("pair", list("first", "X"), list("second", "Y"))))));
-
write_eval(w);
write_initial(w);
}
:start-at: void write(std::ostream &out)
:end-at: }
For the ``write_eval`` method, the main differences are syntactical. First we
change the function declaration line for the Rosette style which drops the
@ -371,7 +392,7 @@ variable, ``[name]_initial``, can then be used in the ``[name]`` function call;
allowing the Rosette code to be used in the generation of the ``next_state``,
whereas the SMT-LIB code can only verify that a given ``next_state`` is correct.
.. literalinclude:: /code_examples/functional/rosette.diff
.. literalinclude:: /generated/functional/rosette.diff
:language: diff
:caption: diff of ``Module::write_initial()`` method
:start-at: void write_initial
@ -396,7 +417,7 @@ an additional line declaring that everything in the file should be exported for
use; allowing the file to be treated as a Racket package with structs and
mapping function available for use externally.
.. literalinclude:: /code_examples/functional/rosette.diff
.. literalinclude:: /generated/functional/rosette.diff
:language: diff
:caption: relevant portion of diff of ``Backend::execute()`` method
:start-at: lang rosette/safe