InferArguments.cpp
#include <set>
#include <string>
#include <vector>
#include "ExternFuncArgument.h"
#include "Function.h"
#include "IRVisitor.h"
#include "InferArguments.h"
namespace Halide {
namespace Internal {
using std::set;
using std::string;
using std::vector;
namespace {
class InferArguments : public IRGraphVisitor {
public:
vector<InferredArgument> &args;
InferArguments(vector<InferredArgument> &a, const vector<Function> &o, const Stmt &body)
: args(a), outputs(o) {
args.clear();
for (const Function &f : outputs) {
visit_function(f);
}
if (body.defined()) {
body.accept(this);
}
}
private:
vector<Function> outputs;
set<string> visited_functions;
using IRGraphVisitor::visit;
bool already_have(const string &name) {
// Ignore dependencies on the output buffers
for (const Function &output : outputs) {
if (name == output.name() || starts_with(name, output.name() + ".")) {
return true;
}
}
for (const InferredArgument &arg : args) {
if (arg.arg.name == name) {
return true;
}
}
return false;
}
void visit_exprs(const vector<Expr> &v) {
for (Expr i : v) {
visit_expr(i);
}
}
void visit_expr(const Expr &e) {
if (!e.defined()) return;
e.accept(this);
}
void visit_function(const Function &func) {
if (visited_functions.count(func.name())) return;
visited_functions.insert(func.name());
func.accept(this);
// Function::accept hits all the Expr children of the
// Function, but misses the buffers and images that might be
// extern arguments.
if (func.has_extern_definition()) {
for (const ExternFuncArgument &extern_arg : func.extern_arguments()) {
if (extern_arg.is_func()) {
visit_function(Function(extern_arg.func));
} else if (extern_arg.is_buffer()) {
include_buffer(extern_arg.buffer);
} else if (extern_arg.is_image_param()) {
include_parameter(extern_arg.image_param);
}
}
}
}
void include_parameter(const Parameter &p) {
if (!p.defined()) return;
if (already_have(p.name())) return;
ArgumentEstimates argument_estimates = p.get_argument_estimates();
if (!p.is_buffer()) {
argument_estimates.scalar_def = p.scalar_expr();
argument_estimates.scalar_min = p.min_value();
argument_estimates.scalar_max = p.max_value();
argument_estimates.scalar_estimate = p.estimate();
}
InferredArgument a = {
Argument(p.name(),
p.is_buffer() ? Argument::InputBuffer : Argument::InputScalar,
p.type(), p.dimensions(), argument_estimates),
p,
Buffer<>()};
args.push_back(a);
// Visit child expressions
visit_expr(argument_estimates.scalar_def);
visit_expr(argument_estimates.scalar_min);
visit_expr(argument_estimates.scalar_max);
visit_expr(argument_estimates.scalar_estimate);
for (const auto &be : argument_estimates.buffer_estimates) {
visit_expr(be.min);
visit_expr(be.extent);
}
if (p.is_buffer()) {
for (int i = 0; i < p.dimensions(); i++) {
visit_expr(p.min_constraint(i));
visit_expr(p.extent_constraint(i));
visit_expr(p.stride_constraint(i));
}
}
}
void include_buffer(const Buffer<> &b) {
if (!b.defined()) return;
if (already_have(b.name())) return;
InferredArgument a = {
Argument(b.name(), Argument::InputBuffer, b.type(), b.dimensions(), ArgumentEstimates{}),
Parameter(),
b};
args.push_back(a);
}
void visit(const Load *op) override {
IRGraphVisitor::visit(op);
include_parameter(op->param);
include_buffer(op->image);
}
void visit(const Variable *op) override {
IRGraphVisitor::visit(op);
include_parameter(op->param);
include_buffer(op->image);
}
void visit(const Call *op) override {
IRGraphVisitor::visit(op);
if (op->func.defined()) {
Function fn(op->func);
visit_function(fn);
}
include_buffer(op->image);
include_parameter(op->param);
}
};
} // namespace
vector<InferredArgument> infer_arguments(const Stmt &body, const vector<Function> &outputs) {
vector<InferredArgument> inferred_args;
// Infer an arguments vector by walking the IR
InferArguments infer_args(inferred_args,
outputs,
body);
// Sort the Arguments with all buffers first (alphabetical by name),
// followed by all non-buffers (alphabetical by name).
std::sort(inferred_args.begin(), inferred_args.end());
return inferred_args;
}
} // namespace Internal
} // namespace Halide