From 13531e867aedbfed5bedf5c463b63994d6dedfe2 Mon Sep 17 00:00:00 2001 From: theraven Date: Tue, 29 Dec 2015 16:29:42 +0000 Subject: Improvements to BSD-licensed DTC. - Added an expression parser so that expressions from headers are now working - Fixed missing null terminators on cross references - Disabled exceptions / RTTI in the build for smaller binaries - Changed phandle order generation to be identical to GPL'd dtc --- usr.bin/dtc/Makefile | 2 +- usr.bin/dtc/checking.cc | 4 +- usr.bin/dtc/checking.hh | 12 +- usr.bin/dtc/dtb.hh | 4 +- usr.bin/dtc/fdt.cc | 258 +++++++++++--------- usr.bin/dtc/fdt.hh | 61 ++++- usr.bin/dtc/input_buffer.cc | 564 +++++++++++++++++++++++++++++++++++++++++++- usr.bin/dtc/input_buffer.hh | 23 ++ 8 files changed, 792 insertions(+), 136 deletions(-) (limited to 'usr.bin') diff --git a/usr.bin/dtc/Makefile b/usr.bin/dtc/Makefile index a6c722a..a834f62 100644 --- a/usr.bin/dtc/Makefile +++ b/usr.bin/dtc/Makefile @@ -6,7 +6,7 @@ MAN= dtc.1 WARNS?= 3 -CXXFLAGS+= -std=c++11 +CXXFLAGS+= -std=c++11 -fno-rtti -fno-exceptions NO_SHARED?=NO diff --git a/usr.bin/dtc/checking.cc b/usr.bin/dtc/checking.cc index 70731ce..26cbbe2 100644 --- a/usr.bin/dtc/checking.cc +++ b/usr.bin/dtc/checking.cc @@ -51,7 +51,7 @@ namespace struct address_cells_checker : public checker { address_cells_checker(const char *name) : checker(name) {} - virtual bool check_node(device_tree *tree, const node_ptr &n) + virtual bool check_node(device_tree *, const node_ptr &n) { // If this has no children, it trivially meets the // conditions. @@ -151,7 +151,7 @@ property_checker::check_property(device_tree *tree, const node_ptr &n, property_ } bool -property_size_checker::check(device_tree *tree, const node_ptr &n, property_ptr p) +property_size_checker::check(device_tree *, const node_ptr &, property_ptr p) { uint32_t psize = 0; for (property::value_iterator i=p->begin(),e=p->end() ; i!=e ; ++i) diff --git a/usr.bin/dtc/checking.hh b/usr.bin/dtc/checking.hh index 34d28c3..e3b3d45 100644 --- a/usr.bin/dtc/checking.hh +++ b/usr.bin/dtc/checking.hh @@ -86,7 +86,7 @@ class checker * Method for checking that a node is valid. The root class version * does nothing, subclasses should override this. */ - virtual bool check_node(device_tree *tree, const node_ptr &n) + virtual bool check_node(device_tree *, const node_ptr &) { return true; } @@ -94,7 +94,7 @@ class checker * Method for checking that a property is valid. The root class * version does nothing, subclasses should override this. */ - virtual bool check_property(device_tree *tree, const node_ptr &n, property_ptr p) + virtual bool check_property(device_tree *, const node_ptr &, property_ptr ) { return true; } @@ -160,7 +160,7 @@ struct property_type_checker : public property_checker { property_type_checker(const char* name, string property_name) : property_checker(name, property_name) {} - virtual bool check(device_tree *tree, const node_ptr &n, property_ptr p) + virtual bool check(device_tree *, const node_ptr &, property_ptr p) { return p->begin() == p->end(); } @@ -175,7 +175,7 @@ struct property_type_checker : public property_checker { property_type_checker(const char* name, string property_name) : property_checker(name, property_name) {} - virtual bool check(device_tree *tree, const node_ptr &n, property_ptr p) + virtual bool check(device_tree *, const node_ptr &, property_ptr p) { return (p->begin() + 1 == p->end()) && p->begin()->is_string(); } @@ -190,7 +190,7 @@ struct property_type_checker : { property_type_checker(const char* name, string property_name) : property_checker(name, property_name) {} - virtual bool check(device_tree *tree, const node_ptr &n, property_ptr p) + virtual bool check(device_tree *, const node_ptr &, property_ptr p) { for (property::value_iterator i=p->begin(),e=p->end() ; i!=e ; ++i) @@ -213,7 +213,7 @@ struct property_type_checker : public property_checker { property_type_checker(const char* name, string property_name) : property_checker(name, property_name) {} - virtual bool check(device_tree *tree, const node_ptr &n, property_ptr p) + virtual bool check(device_tree *tree, const node_ptr &, property_ptr p) { return (p->begin() + 1 == p->end()) && (tree->referenced_node(*p->begin()) != 0); diff --git a/usr.bin/dtc/dtb.hh b/usr.bin/dtc/dtb.hh index a246e96..184369b 100644 --- a/usr.bin/dtc/dtb.hh +++ b/usr.bin/dtc/dtb.hh @@ -186,11 +186,11 @@ class binary_writer : public output_writer * The binary format does not support labels, so this method * does nothing. */ - virtual void write_label(string name) {} + virtual void write_label(string) {} /** * Comments are ignored by the binary writer. */ - virtual void write_comment(string name) {} + virtual void write_comment(string) {} virtual void write_string(string name); virtual void write_data(uint8_t v); virtual void write_data(uint32_t v); diff --git a/usr.bin/dtc/fdt.cc b/usr.bin/dtc/fdt.cc index 3908e0e..23476ae 100644 --- a/usr.bin/dtc/fdt.cc +++ b/usr.bin/dtc/fdt.cc @@ -264,24 +264,6 @@ property::parse_string(input_buffer &input) void property::parse_cells(input_buffer &input, int cell_size) { - unsigned long long cell_max; - switch (cell_size) - { - case 8: - cell_max = UINT8_MAX; - break; - case 16: - cell_max = UINT16_MAX; - break; - case 32: - cell_max = UINT32_MAX; - break; - case 64: - cell_max = UINT64_MAX; - break; - default: - assert(0 && "Invalid cell size!"); - } assert(input[0] == '<'); ++input; property_value v; @@ -327,19 +309,12 @@ property::parse_cells(input_buffer &input, int cell_size) //FIXME: We should support labels in the middle //of these, but we don't. unsigned long long val; - if (!input.consume_integer(val)) + if (!input.consume_integer_expression(val)) { input.parse_error("Expected numbers in array of cells"); valid = false; return; } - if (val > cell_max) - { - fprintf(stderr, "%lld > %lld\n", val, cell_max); - input.parse_error("Value out of range"); - valid = false; - return; - } switch (cell_size) { case 8: @@ -685,6 +660,16 @@ node::parse_name(input_buffer &input, bool &is_property, const char *error) return n; } +void +node::visit(std::function fn) +{ + fn(*this); + for (auto &&c : children) + { + c->visit(fn); + } +} + node::node(input_buffer &structs, input_buffer &strings) : valid(true) { const char *name_start = (const char*)structs; @@ -742,7 +727,7 @@ node::node(input_buffer &structs, input_buffer &strings) : valid(true) valid = false; return; } - properties.push_back(prop); + props.push_back(prop); break; } break; @@ -806,7 +791,7 @@ node::node(input_buffer &input, string n, string l, string a, define_map *define } else { - properties.push_back(p); + props.push_back(p); } } else if (!is_property && input[0] == ('{')) @@ -824,7 +809,7 @@ node::node(input_buffer &input, string n, string l, string a, define_map *define } else if (input.consume(';')) { - properties.push_back(property_ptr(new property(child_name, child_label))); + props.push_back(property_ptr(new property(child_name, child_label))); } else { @@ -857,9 +842,9 @@ node::sort() { std::sort(property_begin(), property_end(), cmp_properties); std::sort(child_begin(), child_end(), cmp_children); - for (child_iterator i=child_begin(), e=child_end() ; i!=e ; ++i) + for (auto &c : child_nodes()) { - (*i)->sort(); + c->sort(); } } @@ -892,7 +877,7 @@ node::parse_dtb(input_buffer &structs, input_buffer &strings) property_ptr node::get_property(string key) { - for (auto &i : properties) + for (auto &i : props) { if (i->get_key() == key) { @@ -914,14 +899,14 @@ node::merge_node(node_ptr other) // large numbers of properties, but for typical usage the // entire vector will fit (easily) into cache, so iterating // over it repeatedly isn't that expensive. - for (auto &p : other->properties) + for (auto &p : other->properties()) { bool found = false; - for (auto i=property_begin(), e=property_end() ; i!=e ; ++i) + for (auto &mp : properties()) { - if ((*i)->get_key() == p->get_key()) + if (mp->get_key() == p->get_key()) { - *i = p; + mp = p; found = true; break; } @@ -964,13 +949,13 @@ node::write(dtb::output_writer &writer, dtb::string_table &strings) writer.write_comment(name); writer.write_data(name_buffer); writer.write_data((uint8_t)0); - for (auto i=property_begin(), e=property_end() ; i!=e ; ++i) + for (auto p : properties()) { - (*i)->write(writer, strings); + p->write(writer, strings); } - for (child_iterator i=child_begin(), e=child_end() ; i!=e ; ++i) + for (auto &c : child_nodes()) { - (*i)->write(writer, strings); + c->write(writer, strings); } writer.write_token(dtb::FDT_END_NODE); } @@ -999,13 +984,13 @@ node::write_dts(FILE *file, int indent) unit_address.print(file); } fputs(" {\n\n", file); - for (auto i=property_begin(), e=property_end() ; i!=e ; ++i) + for (auto p : properties()) { - (*i)->write_dts(file, indent+1); + p->write_dts(file, indent+1); } - for (child_iterator i=child_begin(), e=child_end() ; i!=e ; ++i) + for (auto &c : child_nodes()) { - (*i)->write_dts(file, indent+1); + c->write_dts(file, indent+1); } for (int i=0 ; ichild_begin(), e=n->child_end() ; i!=e ; ++i) + for (auto &c : n->child_nodes()) { - collect_names_recursive(*i, path); + collect_names_recursive(c, path); } path.pop_back(); // Now we collect the phandles and properties that reference // other nodes. - for (auto i=n->property_begin(), e=n->property_end() ; i!=e ; ++i) + for (auto &p : n->properties()) { - for (property::value_iterator p=(*i)->begin(),pe=(*i)->end() ; p!=pe ; ++p) + for (auto &v : *p) { - if (p->is_phandle()) + if (v.is_phandle()) { - phandles.push_back(&*p); + phandles.push_back(&v); } - if (p->is_cross_reference()) + if (v.is_cross_reference()) { - cross_references.push_back(&*p); + cross_references.push_back(&v); } } - if ((*i)->get_key() == string("phandle") || - (*i)->get_key() == string("linux,phandle")) + if (p->get_key() == string("phandle") || + p->get_key() == string("linux,phandle")) { - if ((*i)->begin()->byte_data.size() != 4) + if (p->begin()->byte_data.size() != 4) { fprintf(stderr, "Invalid phandle value for node "); n->name.dump(); @@ -1071,7 +1056,7 @@ device_tree::collect_names_recursive(node_ptr &n, node_path &path) } else { - uint32_t phandle = (*i)->begin()->get_as_uint32(); + uint32_t phandle = p->begin()->get_as_uint32(); used_phandles.insert(std::make_pair(phandle, n.get())); } } @@ -1104,12 +1089,33 @@ device_tree::resolve_cross_references() { pv->byte_data.push_back('@'); p->second.push_to_buffer(pv->byte_data); + pv->byte_data.push_back(0); } } } - uint32_t phandle = 1; + std::unordered_set phandle_set; for (auto &i : phandles) { + phandle_set.insert(i); + } + std::vector sorted_phandles; + root->visit([&](node &n) { + for (auto &p : n.properties()) + { + for (auto &v : *p) + { + if (phandle_set.count(&v)) + { + sorted_phandles.push_back(&v); + } + } + } + }); + assert(sorted_phandles.size() == phandles.size()); + + uint32_t phandle = 1; + for (auto &i : sorted_phandles) + { string target_name = i->string_data; node *target = node_names[target_name]; if (target == 0) @@ -1163,94 +1169,111 @@ device_tree::resolve_cross_references() } } -void -device_tree::parse_file(input_buffer &input, +bool +device_tree::parse_include(input_buffer &input, const std::string &dir, std::vector &roots, FILE *depfile, bool &read_header) { - input.next_token(); - // Read the header - if (input.consume("/dts-v1/;")) + if (!input.consume("/include/")) { - read_header = true; + return false; } - input.next_token(); - while(input.consume("/include/")) + bool reallyInclude = true; + if (input.consume("if ")) { - bool reallyInclude = true; - if (input.consume("if ")) - { - input.next_token(); - string name = string::parse_property_name(input); - // XXX: Error handling - if (defines.find(name) == defines.end()) - { - reallyInclude = false; - } - input.consume('/'); - } input.next_token(); - if (!input.consume('"')) + string name = string::parse_property_name(input); + // XXX: Error handling + if (defines.find(name) == defines.end()) { - input.parse_error("Expected quoted filename"); - valid = false; - return; + reallyInclude = false; } - int length = 0; - while (input[length] != '"') length++; + input.consume('/'); + } + input.next_token(); + if (!input.consume('"')) + { + input.parse_error("Expected quoted filename"); + valid = false; + return false; + } + int length = 0; + while (input[length] != '"') length++; - std::string file((const char*)input, length); - std::string include_file = dir + '/' + file; - assert(input.consume(file.c_str())); + std::string file((const char*)input, length); + std::string include_file = dir + '/' + file; + input.consume(file.c_str()); + if (!reallyInclude) + { input.consume('"'); input.next_token(); - if (!reallyInclude) - { - continue; - } + return true; + } - input_buffer *include_buffer = buffer_for_file(include_file.c_str()); + input_buffer *include_buffer = buffer_for_file(include_file.c_str(), false); - if (include_buffer == 0) + if (include_buffer == 0) + { + for (auto i : include_paths) { - for (auto i : include_paths) + include_file = i + '/' + file; + include_buffer = buffer_for_file(include_file.c_str()); + if (include_buffer != 0) { - include_file = i + '/' + file; - include_buffer = buffer_for_file(include_file.c_str()); - if (include_buffer != 0) - { - break; - } + break; } } - if (depfile != 0) - { - putc(' ', depfile); - fputs(include_file.c_str(), depfile); - } - if (include_buffer == 0) - { - valid = false; - return; - } - parse_file(*include_buffer, dir, roots, depfile, read_header); } + if (depfile != 0) + { + putc(' ', depfile); + fputs(include_file.c_str(), depfile); + } + if (include_buffer == 0) + { + input.parse_error("Unable to locate input file"); + input.consume('"'); + input.next_token(); + valid = false; + return true; + } + input.consume('"'); + input.next_token(); + parse_file(*include_buffer, dir, roots, depfile, read_header); + return true; +} + +void +device_tree::parse_file(input_buffer &input, + const std::string &dir, + std::vector &roots, + FILE *depfile, + bool &read_header) +{ + input.next_token(); + // Read the header + if (input.consume("/dts-v1/;")) + { + read_header = true; + } + input.next_token(); input.next_token(); if (!read_header) { input.parse_error("Expected /dts-v1/; version string"); } + while(parse_include(input, dir, roots, depfile, read_header)) {} // Read any memory reservations while(input.consume("/memreserve/")) { unsigned long long start, len; input.next_token(); // Read the start and length. - if (!(input.consume_integer(start) && + if (!(input.consume_integer_expression(start) && (input.next_token(), - input.consume_integer(len)))) + input.consume_integer_expression(len)))) { input.parse_error("Expected size on /memreserve/ node."); } @@ -1259,6 +1282,7 @@ device_tree::parse_file(input_buffer &input, reservations.push_back(reservation(start, len)); } input.next_token(); + while(parse_include(input, dir, roots, depfile, read_header)) {} while (valid && !input.finished()) { node_ptr n; @@ -1287,11 +1311,12 @@ device_tree::parse_file(input_buffer &input, valid = false; } input.next_token(); + while(parse_include(input, dir, roots, depfile, read_header)) {} } } input_buffer* -device_tree::buffer_for_file(const char *path) +device_tree::buffer_for_file(const char *path, bool warn) { if (string(path) == string("-")) { @@ -1306,7 +1331,10 @@ device_tree::buffer_for_file(const char *path) int source = open(path, O_RDONLY); if (source == -1) { - fprintf(stderr, "Unable to open file '%s'. %s\n", path, strerror(errno)); + if (warn) + { + fprintf(stderr, "Unable to open file '%s'. %s\n", path, strerror(errno)); + } return 0; } struct stat st; @@ -1447,7 +1475,7 @@ device_tree::write_dts(int fd) } void -device_tree::parse_dtb(const char *fn, FILE *depfile) +device_tree::parse_dtb(const char *fn, FILE *) { input_buffer *in = buffer_for_file(fn); if (in == 0) diff --git a/usr.bin/dtc/fdt.hh b/usr.bin/dtc/fdt.hh index 7340a73..5f53f5a 100644 --- a/usr.bin/dtc/fdt.hh +++ b/usr.bin/dtc/fdt.hh @@ -36,6 +36,7 @@ #include #include #include +#include #include "util.hh" #include "string.hh" @@ -402,11 +403,37 @@ class node * The type for the property vector. */ typedef std::vector property_vector; + /** + * Iterator type for child nodes. + */ + typedef std::vector::iterator child_iterator; private: /** + * Adaptor to use children in range-based for loops. + */ + struct child_range + { + child_range(node &nd) : n(nd) {} + child_iterator begin() { return n.child_begin(); } + child_iterator end() { return n.child_end(); } + private: + node &n; + }; + /** + * Adaptor to use properties in range-based for loops. + */ + struct property_range + { + property_range(node &nd) : n(nd) {} + property_vector::iterator begin() { return n.property_begin(); } + property_vector::iterator end() { return n.property_end(); } + private: + node &n; + }; + /** * The properties contained within this node. */ - property_vector properties; + property_vector props; /** * The children of this node. */ @@ -458,10 +485,6 @@ class node */ void sort(); /** - * Iterator type for child nodes. - */ - typedef std::vector::iterator child_iterator; - /** * Returns an iterator for the first child of this node. */ inline child_iterator child_begin() @@ -475,19 +498,27 @@ class node { return children.end(); } + inline child_range child_nodes() + { + return child_range(*this); + } + inline property_range properties() + { + return property_range(*this); + } /** * Returns an iterator after the last property of this node. */ inline property_vector::iterator property_begin() { - return properties.begin(); + return props.begin(); } /** * Returns an iterator for the first property of this node. */ inline property_vector::iterator property_end() { - return properties.end(); + return props.end(); } /** * Factory method for constructing a new node. Attempts to parse a @@ -519,7 +550,7 @@ class node */ inline void add_property(property_ptr &p) { - properties.push_back(p); + props.push_back(p); } /** * Merges a node into this one. Any properties present in both are @@ -539,6 +570,10 @@ class node * with this number of tabs. */ void write_dts(FILE *file, int indent); + /** + * Recursively visit this node and then its children. + */ + void visit(std::function); }; /** @@ -683,6 +718,14 @@ class device_tree */ void resolve_cross_references(); /** + * Parse a top-level include directive. + */ + bool parse_include(input_buffer &input, + const std::string &dir, + std::vector &roots, + FILE *depfile, + bool &read_header); + /** * Parses a dts file in the given buffer and adds the roots to the parsed * set. The `read_header` argument indicates whether the header has * already been read. Some dts files place the header in an include, @@ -698,7 +741,7 @@ class device_tree * object then keeps a reference to it, ensuring that it is not * deallocated until the device tree is destroyed. */ - input_buffer *buffer_for_file(const char *path); + input_buffer *buffer_for_file(const char *path, bool warn=true); /** * Template function that writes a dtb blob using the specified writer. * The writer defines the output format (assembly, blob). diff --git a/usr.bin/dtc/input_buffer.cc b/usr.bin/dtc/input_buffer.cc index fe8c402..6d48adc 100644 --- a/usr.bin/dtc/input_buffer.cc +++ b/usr.bin/dtc/input_buffer.cc @@ -37,6 +37,10 @@ #include #include #include +#include +#ifndef NDEBUG +#include +#endif #include @@ -49,7 +53,6 @@ namespace dtc { - void input_buffer::skip_spaces() { @@ -131,6 +134,563 @@ input_buffer::consume_integer(unsigned long long &outInt) return true; } +namespace { + +/** + * Convenience typedef for the type that we use for all values. + */ +typedef unsigned long long valty; + +/** + * Expression tree currently being parsed. + */ +struct expression +{ + /** + * Evaluate this node, taking into account operator precedence. + */ + virtual valty operator()() = 0; + /** + * Returns the precedence of this node. Lower values indicate higher + * precedence. + */ + virtual int precedence() = 0; + virtual ~expression() {} +#ifndef NDEBUG + /** + * Dumps this expression to `std::cerr`, appending a newline if `nl` is + * `true`. + */ + void dump(bool nl=false) + { + if (this == nullptr) + { + std::cerr << "{nullptr}\n"; + return; + } + dump_impl(); + if (nl) + { + std::cerr << '\n'; + } + } + private: + /** + * Method that sublcasses override to implement the behaviour of `dump()`. + */ + virtual void dump_impl() = 0; +#endif +}; + +/** + * Expression wrapping a single integer. Leaf nodes in the expression tree. + */ +class terminal_expr : public expression +{ + /** + * The value that this wraps. + */ + valty val; + /** + * Evaluate. Trivially returns the value that this class wraps. + */ + valty operator()() override + { + return val; + } + int precedence() override + { + return 0; + } + public: + /** + * Constructor. + */ + terminal_expr(valty v) : val(v) {} +#ifndef NDEBUG + void dump_impl() override { std::cerr << val; } +#endif +}; + +/** + * Parenthetical expression. Exists to make the contents opaque. + */ +struct paren_expression : public expression +{ + /** + * The expression within the parentheses. + */ + expression_ptr subexpr; + /** + * Constructor. Takes the child expression as the only argument. + */ + paren_expression(expression_ptr p) : subexpr(std::move(p)) {} + int precedence() override + { + return 0; + } + /** + * Evaluate - just forwards to the underlying expression. + */ + valty operator()() override + { + return (*subexpr)(); + } +#ifndef NDEBUG + void dump_impl() override + { + std::cerr << " ("; + subexpr->dump(); + std::cerr << ") "; + } +#endif +}; + +/** + * Template class for unary operators. The `OpChar` template parameter is + * solely for debugging and makes it easy to print the expression. The `Op` + * template parameter is a function object that implements the operator that + * this class provides. Most of these are provided by the `` + * header. + */ +template +class unary_operator : public expression +{ + /** + * The subexpression for this unary operator. + */ + expression_ptr subexpr; + valty operator()() override + { + Op op; + return op((*subexpr)()); + } + /** + * All unary operators have the same precedence. They are all evaluated + * before binary expressions, but after parentheses. + */ + int precedence() override + { + return 3; + } + public: + unary_operator(expression_ptr p) : subexpr(std::move(p)) {} +#ifndef NDEBUG + void dump_impl() override + { + std::cerr << OpChar; + subexpr->dump(); + } +#endif +}; + +/** + * Abstract base class for binary operators. Allows the tree to be modified + * without knowing what the operations actually are. + */ +struct binary_operator_base : public expression +{ + /** + * The left side of the expression. + */ + expression_ptr lhs; + /** + * The right side of the expression. + */ + expression_ptr rhs; + /** + * Insert a node somewhere down the path of left children, until it would + * be preempting something that should execute first. + */ + void insert_left(binary_operator_base *new_left) + { + if (lhs->precedence() < new_left->precedence()) + { + new_left->rhs = std::move(lhs); + lhs.reset(new_left); + } + else + { + static_cast(lhs.get())->insert_left(new_left); + } + } +}; + +/** + * Template class for binary operators. The precedence and the operation are + * provided as template parameters. + */ +template +struct binary_operator : public binary_operator_base +{ + valty operator()() override + { + Op op; + return op((*lhs)(), (*rhs)()); + } + int precedence() override + { + return Precedence; + } +#ifdef NDEBUG + /** + * Constructor. Takes the name of the operator as an argument, for + * debugging. Only stores it in debug mode. + */ + binary_operator(const char *) {} +#else + const char *opName; + binary_operator(const char *o) : opName(o) {} + void dump_impl() override + { + lhs->dump(); + std::cerr << opName; + rhs->dump(); + } +#endif +}; + +/** + * Ternary conditional operators (`cond ? true : false`) are a special case - + * there are no other ternary operators. + */ +class ternary_conditional_operator : public expression +{ + /** + * The condition for the clause. + */ + expression_ptr cond; + /** + * The expression that this evaluates to if the condition is true. + */ + expression_ptr lhs; + /** + * The expression that this evaluates to if the condition is false. + */ + expression_ptr rhs; + valty operator()() override + { + return (*cond)() ? (*lhs)() : (*rhs)(); + } + int precedence() override + { + // The actual precedence of a ternary conditional operator is 15, but + // its associativity is the opposite way around to the other operators, + // so we fudge it slightly. + return 3; + } +#ifndef NDEBUG + void dump_impl() override + { + cond->dump(); + std::cerr << " ? "; + lhs->dump(); + std::cerr << " : "; + rhs->dump(); + } +#endif + public: + ternary_conditional_operator(expression_ptr c, + expression_ptr l, + expression_ptr r) : + cond(std::move(c)), lhs(std::move(l)), rhs(std::move(r)) {} +}; + +template +struct lshift +{ + constexpr T operator()(const T &lhs, const T &rhs) const + { + return lhs << rhs; + } +}; +template +struct rshift +{ + constexpr T operator()(const T &lhs, const T &rhs) const + { + return lhs >> rhs; + } +}; +template +struct unary_plus +{ + constexpr T operator()(const T &val) const + { + return +val; + } +}; +// TODO: Replace with std::bit_not once we can guarantee C++14 as a baseline. +template +struct bit_not +{ + constexpr T operator()(const T &val) const + { + return ~val; + } +}; + +} // anonymous namespace + + +expression_ptr input_buffer::parse_binary_expression(expression_ptr lhs) +{ + next_token(); + binary_operator_base *expr = nullptr; + char op = ((*this)[0]); + switch (op) + { + default: + return lhs; + case '+': + expr = new binary_operator<6, std::plus>("+"); + break; + case '-': + expr = new binary_operator<6, std::minus>("-"); + break; + case '%': + expr = new binary_operator<5, std::modulus>("%"); + break; + case '*': + expr = new binary_operator<5, std::multiplies>("*"); + break; + case '/': + expr = new binary_operator<5, std::divides>("/"); + break; + case '<': + cursor++; + switch ((*this)[0]) + { + default: + parse_error("Invalid operator"); + return nullptr; + case ' ': + case '(': + case '0'...'9': + cursor--; + expr = new binary_operator<8, std::less>("<"); + break; + case '=': + expr = new binary_operator<8, std::less_equal>("<="); + break; + case '<': + expr = new binary_operator<7, lshift>("<<"); + break; + } + break; + case '>': + cursor++; + switch ((*this)[0]) + { + default: + parse_error("Invalid operator"); + return nullptr; + case '(': + case ' ': + case '0'...'9': + cursor--; + expr = new binary_operator<8, std::greater>(">"); + break; + case '=': + expr = new binary_operator<8, std::greater_equal>(">="); + break; + case '>': + expr = new binary_operator<7, rshift>(">>"); + break; + return lhs; + } + break; + case '=': + if ((*this)[1] != '=') + { + parse_error("Invalid operator"); + return nullptr; + } + consume('='); + expr = new binary_operator<9, std::equal_to>("=="); + break; + case '!': + if ((*this)[1] != '=') + { + parse_error("Invalid operator"); + return nullptr; + } + cursor++; + expr = new binary_operator<9, std::not_equal_to>("!="); + break; + case '&': + if ((*this)[1] == '&') + { + expr = new binary_operator<13, std::logical_and>("&&"); + } + else + { + expr = new binary_operator<10, std::bit_and>("&"); + } + break; + case '|': + if ((*this)[1] == '|') + { + expr = new binary_operator<12, std::logical_or>("||"); + } + else + { + expr = new binary_operator<14, std::bit_or>("|"); + } + break; + case '?': + { + consume('?'); + expression_ptr true_case = parse_expression(); + next_token(); + if (!true_case || !consume(':')) + { + parse_error("Expected : in ternary conditional operator"); + return nullptr; + } + expression_ptr false_case = parse_expression(); + if (!false_case) + { + parse_error("Expected false condition for ternary operator"); + return nullptr; + } + return expression_ptr(new ternary_conditional_operator(std::move(lhs), + std::move(true_case), std::move(false_case))); + } + } + cursor++; + next_token(); + expression_ptr e(expr); + expression_ptr rhs(parse_expression()); + if (!rhs) + { + return nullptr; + } + expr->lhs = std::move(lhs); + if (rhs->precedence() < expr->precedence()) + { + expr->rhs = std::move(rhs); + } + else + { + // If we're a normal left-to-right expression, then we need to insert + // this as the far-left child node of the rhs expression + binary_operator_base *rhs_op = + static_cast(rhs.get()); + rhs_op->insert_left(expr); + e.release(); + return rhs; + } + return e; +} + +expression_ptr input_buffer::parse_expression(bool stopAtParen) +{ + next_token(); + unsigned long long leftVal; + expression_ptr lhs; + switch ((*this)[0]) + { + case '0'...'9': + if (!consume_integer(leftVal)) + { + return nullptr; + } + lhs.reset(new terminal_expr(leftVal)); + break; + case '(': + { + consume('('); + expression_ptr &&subexpr = parse_expression(); + if (!subexpr) + { + return nullptr; + } + lhs.reset(new paren_expression(std::move(subexpr))); + if (!consume(')')) + { + return nullptr; + } + if (stopAtParen) + { + return lhs; + } + break; + } + case '+': + { + consume('+'); + expression_ptr &&subexpr = parse_expression(); + if (!subexpr) + { + return nullptr; + } + lhs.reset(new unary_operator<'+', unary_plus>(std::move(subexpr))); + break; + } + case '-': + { + consume('-'); + expression_ptr &&subexpr = parse_expression(); + if (!subexpr) + { + return nullptr; + } + lhs.reset(new unary_operator<'-', std::negate>(std::move(subexpr))); + break; + } + case '!': + { + consume('!'); + expression_ptr &&subexpr = parse_expression(); + if (!subexpr) + { + return nullptr; + } + lhs.reset(new unary_operator<'!', std::logical_not>(std::move(subexpr))); + break; + } + case '~': + { + consume('~'); + expression_ptr &&subexpr = parse_expression(); + if (!subexpr) + { + return nullptr; + } + lhs.reset(new unary_operator<'~', bit_not>(std::move(subexpr))); + break; + } + } + if (!lhs) + { + return nullptr; + } + return parse_binary_expression(std::move(lhs)); +} + +bool +input_buffer::consume_integer_expression(unsigned long long &outInt) +{ + switch ((*this)[0]) + { + case '(': + { + expression_ptr e(parse_expression(true)); + if (!e) + { + return false; + } + outInt = (*e)(); + return true; + } + case '0'...'9': + return consume_integer(outInt); + default: + return false; + } +} + bool input_buffer::consume_hex_byte(uint8_t &outByte) { @@ -222,12 +782,14 @@ input_buffer::parse_error(const char *msg) putc('^', stderr); putc('\n', stderr); } +#ifndef NDEBUG void input_buffer::dump() { fprintf(stderr, "Current cursor: %d\n", cursor); fwrite(&buffer[cursor], size-cursor, 1, stderr); } +#endif mmap_input_buffer::mmap_input_buffer(int fd) : input_buffer(0, 0) { diff --git a/usr.bin/dtc/input_buffer.hh b/usr.bin/dtc/input_buffer.hh index 5b1f5d6..1a87911 100644 --- a/usr.bin/dtc/input_buffer.hh +++ b/usr.bin/dtc/input_buffer.hh @@ -38,6 +38,11 @@ namespace dtc { +namespace { +struct expression; +typedef std::unique_ptr expression_ptr; +} + /** * Class encapsulating the input file. Can be used as a const char*, but has * range checking. Attempting to access anything out of range will return a 0 @@ -62,6 +67,17 @@ class input_buffer int size; private: /** + * Parse an expression. If `stopAtParen` is set, then only parse a number + * or a parenthetical expression, otherwise assume that either is the + * left-hand side of a binary expression and try to parse the right-hand + * side. + */ + expression_ptr parse_expression(bool stopAtParen=false); + /** + * Parse a binary expression, having already parsed the right-hand side. + */ + expression_ptr parse_binary_expression(expression_ptr lhs); + /** * The current place in the buffer where we are reading. This class * keeps a separate size, pointer, and cursor so that we can move * forwards and backwards and still have checks that we haven't fallen @@ -187,6 +203,11 @@ class input_buffer */ bool consume_integer(unsigned long long &outInt); /** + * Reads an arithmetic expression (containing any of the normal C + * operators), evaluates it, and returns the result. + */ + bool consume_integer_expression(unsigned long long &outInt); + /** * Template function that consumes a binary value in big-endian format * from the input stream. Returns true and advances the cursor if * there is a value of the correct size. This function assumes that @@ -233,12 +254,14 @@ class input_buffer * Prints a message indicating the location of a parse error. */ void parse_error(const char *msg); +#ifndef NDEBUG /** * Dumps the current cursor value and the unconsumed values in the * input buffer to the standard error. This method is intended solely * for debugging. */ void dump(); +#endif }; /** * Explicit specialisation for reading a single byte. -- cgit v1.1