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ton/tolk/pipe-find-unused-symbols.cpp

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[Tolk] Compilation pipeline, register global symbols in advance Since I've implemented AST, now I can drop forward declarations. Instead, I traverse AST of all files and register global symbols (functions, constants, global vars) as a separate step, in advance. That's why, while converting AST to Expr/Op, all available symbols are already registered. This greatly simplifies "intermediate state" of yet unknown functions and checking them afterward. Redeclaration of local variables (inside the same scope) is now also prohibited.
2024-10-31 07:04:58 +00:00
/*
This file is part of TON Blockchain source code.
TON Blockchain is free software; you can redistribute it and/or
modify it under the terms of the GNU General Public License
as published by the Free Software Foundation; either version 2
of the License, or (at your option) any later version.
TON Blockchain is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with TON Blockchain. If not, see <http://www.gnu.org/licenses/>.
In addition, as a special exception, the copyright holders give permission
to link the code of portions of this program with the OpenSSL library.
You must obey the GNU General Public License in all respects for all
of the code used other than OpenSSL. If you modify file(s) with this
exception, you may extend this exception to your version of the file(s),
but you are not obligated to do so. If you do not wish to do so, delete this
exception statement from your version. If you delete this exception statement
from all source files in the program, then also delete it here.
*/
#include "tolk.h"
#include "compiler-state.h"
/*
[Tolk] AST-based semantic analysis, get rid of Expr This is a huge refactoring focusing on untangling compiler internals (previously forked from FunC). The goal is to convert AST directly to Op (a kind of IR representation), doing all code analysis at AST level. Noteable changes: - AST-based semantic kernel includes: registering global symbols, scope handling and resolving local/global identifiers, lvalue/rvalue calc and check, implicit return detection, mutability analysis, pure/impure validity checks, simple constant folding - values of `const` variables are calculated NOT based on CodeBlob, but via a newly-introduced AST-based constant evaluator - AST vertices are now inherited from expression/statement/other; expression vertices have common properties (TypeExpr, lvalue/rvalue) - symbol table is rewritten completely, SymDef/SymVal no longer exist, lexer now doesn't need to register identifiers - AST vertices have references to symbols, filled at different stages of pipeline - the remaining "FunC legacy part" is almost unchanged besides Expr which was fully dropped; AST is converted to Ops (IR) directly
2024-12-16 18:19:45 +00:00
* This pipe finds unused symbols (global functions and variables) to strip them off codegen.
* It happens after converting AST to Op, so it does not traverse AST.
* In the future, when control flow graph is introduced, this should be done at AST level.
[Tolk] Compilation pipeline, register global symbols in advance Since I've implemented AST, now I can drop forward declarations. Instead, I traverse AST of all files and register global symbols (functions, constants, global vars) as a separate step, in advance. That's why, while converting AST to Expr/Op, all available symbols are already registered. This greatly simplifies "intermediate state" of yet unknown functions and checking them afterward. Redeclaration of local variables (inside the same scope) is now also prohibited.
2024-10-31 07:04:58 +00:00
*/
namespace tolk {
static void mark_function_used_dfs(const std::unique_ptr<Op>& op);
[Tolk] AST-based semantic analysis, get rid of Expr This is a huge refactoring focusing on untangling compiler internals (previously forked from FunC). The goal is to convert AST directly to Op (a kind of IR representation), doing all code analysis at AST level. Noteable changes: - AST-based semantic kernel includes: registering global symbols, scope handling and resolving local/global identifiers, lvalue/rvalue calc and check, implicit return detection, mutability analysis, pure/impure validity checks, simple constant folding - values of `const` variables are calculated NOT based on CodeBlob, but via a newly-introduced AST-based constant evaluator - AST vertices are now inherited from expression/statement/other; expression vertices have common properties (TypeExpr, lvalue/rvalue) - symbol table is rewritten completely, SymDef/SymVal no longer exist, lexer now doesn't need to register identifiers - AST vertices have references to symbols, filled at different stages of pipeline - the remaining "FunC legacy part" is almost unchanged besides Expr which was fully dropped; AST is converted to Ops (IR) directly
2024-12-16 18:19:45 +00:00
static void mark_function_used(const FunctionData* fun_ref) {
[Tolk] Rewrite the type system from Hindley-Milner to static typing FunC's (and Tolk's before this PR) type system is based on Hindley-Milner. This is a common approach for functional languages, where types are inferred from usage through unification. As a result, type declarations are not necessary: () f(a,b) { return a+b; } // a and b now int, since `+` (int, int) While this approach works for now, problems arise with the introduction of new types like bool, where `!x` must handle both int and bool. It will also become incompatible with int32 and other strict integers. This will clash with structure methods, struggle with proper generics, and become entirely impractical for union types. This PR completely rewrites the type system targeting the future. 1) type of any expression is inferred and never changed 2) this is available because dependent expressions already inferred 3) forall completely removed, generic functions introduced (they work like template functions actually, instantiated while inferring) 4) instantiation `<...>` syntax, example: `t.tupleAt<int>(0)` 5) `as` keyword, for example `t.tupleAt(0) as int` 6) methods binding is done along with type inferring, not before ("before", as worked previously, was always a wrong approach)
2024-12-30 15:31:27 +00:00
if (!fun_ref->is_code_function() || fun_ref->is_really_used()) { // already handled
[Tolk] Compilation pipeline, register global symbols in advance Since I've implemented AST, now I can drop forward declarations. Instead, I traverse AST of all files and register global symbols (functions, constants, global vars) as a separate step, in advance. That's why, while converting AST to Expr/Op, all available symbols are already registered. This greatly simplifies "intermediate state" of yet unknown functions and checking them afterward. Redeclaration of local variables (inside the same scope) is now also prohibited.
2024-10-31 07:04:58 +00:00
return;
}
[Tolk] AST-based semantic analysis, get rid of Expr This is a huge refactoring focusing on untangling compiler internals (previously forked from FunC). The goal is to convert AST directly to Op (a kind of IR representation), doing all code analysis at AST level. Noteable changes: - AST-based semantic kernel includes: registering global symbols, scope handling and resolving local/global identifiers, lvalue/rvalue calc and check, implicit return detection, mutability analysis, pure/impure validity checks, simple constant folding - values of `const` variables are calculated NOT based on CodeBlob, but via a newly-introduced AST-based constant evaluator - AST vertices are now inherited from expression/statement/other; expression vertices have common properties (TypeExpr, lvalue/rvalue) - symbol table is rewritten completely, SymDef/SymVal no longer exist, lexer now doesn't need to register identifiers - AST vertices have references to symbols, filled at different stages of pipeline - the remaining "FunC legacy part" is almost unchanged besides Expr which was fully dropped; AST is converted to Ops (IR) directly
2024-12-16 18:19:45 +00:00
fun_ref->mutate()->assign_is_really_used();
mark_function_used_dfs(std::get<FunctionBodyCode*>(fun_ref->body)->code->ops);
[Tolk] Compilation pipeline, register global symbols in advance Since I've implemented AST, now I can drop forward declarations. Instead, I traverse AST of all files and register global symbols (functions, constants, global vars) as a separate step, in advance. That's why, while converting AST to Expr/Op, all available symbols are already registered. This greatly simplifies "intermediate state" of yet unknown functions and checking them afterward. Redeclaration of local variables (inside the same scope) is now also prohibited.
2024-10-31 07:04:58 +00:00
}
[Tolk] AST-based semantic analysis, get rid of Expr This is a huge refactoring focusing on untangling compiler internals (previously forked from FunC). The goal is to convert AST directly to Op (a kind of IR representation), doing all code analysis at AST level. Noteable changes: - AST-based semantic kernel includes: registering global symbols, scope handling and resolving local/global identifiers, lvalue/rvalue calc and check, implicit return detection, mutability analysis, pure/impure validity checks, simple constant folding - values of `const` variables are calculated NOT based on CodeBlob, but via a newly-introduced AST-based constant evaluator - AST vertices are now inherited from expression/statement/other; expression vertices have common properties (TypeExpr, lvalue/rvalue) - symbol table is rewritten completely, SymDef/SymVal no longer exist, lexer now doesn't need to register identifiers - AST vertices have references to symbols, filled at different stages of pipeline - the remaining "FunC legacy part" is almost unchanged besides Expr which was fully dropped; AST is converted to Ops (IR) directly
2024-12-16 18:19:45 +00:00
static void mark_global_var_used(const GlobalVarData* glob_ref) {
glob_ref->mutate()->assign_is_really_used();
[Tolk] Compilation pipeline, register global symbols in advance Since I've implemented AST, now I can drop forward declarations. Instead, I traverse AST of all files and register global symbols (functions, constants, global vars) as a separate step, in advance. That's why, while converting AST to Expr/Op, all available symbols are already registered. This greatly simplifies "intermediate state" of yet unknown functions and checking them afterward. Redeclaration of local variables (inside the same scope) is now also prohibited.
2024-10-31 07:04:58 +00:00
}
static void mark_function_used_dfs(const std::unique_ptr<Op>& op) {
if (!op) {
return;
}
[Tolk] AST-based semantic analysis, get rid of Expr This is a huge refactoring focusing on untangling compiler internals (previously forked from FunC). The goal is to convert AST directly to Op (a kind of IR representation), doing all code analysis at AST level. Noteable changes: - AST-based semantic kernel includes: registering global symbols, scope handling and resolving local/global identifiers, lvalue/rvalue calc and check, implicit return detection, mutability analysis, pure/impure validity checks, simple constant folding - values of `const` variables are calculated NOT based on CodeBlob, but via a newly-introduced AST-based constant evaluator - AST vertices are now inherited from expression/statement/other; expression vertices have common properties (TypeExpr, lvalue/rvalue) - symbol table is rewritten completely, SymDef/SymVal no longer exist, lexer now doesn't need to register identifiers - AST vertices have references to symbols, filled at different stages of pipeline - the remaining "FunC legacy part" is almost unchanged besides Expr which was fully dropped; AST is converted to Ops (IR) directly
2024-12-16 18:19:45 +00:00
if (op->f_sym) { // for Op::_Call
mark_function_used(op->f_sym);
}
if (op->g_sym) { // for Op::_GlobVar
mark_global_var_used(op->g_sym);
[Tolk] Compilation pipeline, register global symbols in advance Since I've implemented AST, now I can drop forward declarations. Instead, I traverse AST of all files and register global symbols (functions, constants, global vars) as a separate step, in advance. That's why, while converting AST to Expr/Op, all available symbols are already registered. This greatly simplifies "intermediate state" of yet unknown functions and checking them afterward. Redeclaration of local variables (inside the same scope) is now also prohibited.
2024-10-31 07:04:58 +00:00
}
mark_function_used_dfs(op->next);
mark_function_used_dfs(op->block0);
mark_function_used_dfs(op->block1);
}
void pipeline_find_unused_symbols() {
[Tolk] Rewrite the type system from Hindley-Milner to static typing FunC's (and Tolk's before this PR) type system is based on Hindley-Milner. This is a common approach for functional languages, where types are inferred from usage through unification. As a result, type declarations are not necessary: () f(a,b) { return a+b; } // a and b now int, since `+` (int, int) While this approach works for now, problems arise with the introduction of new types like bool, where `!x` must handle both int and bool. It will also become incompatible with int32 and other strict integers. This will clash with structure methods, struggle with proper generics, and become entirely impractical for union types. This PR completely rewrites the type system targeting the future. 1) type of any expression is inferred and never changed 2) this is available because dependent expressions already inferred 3) forall completely removed, generic functions introduced (they work like template functions actually, instantiated while inferring) 4) instantiation `<...>` syntax, example: `t.tupleAt<int>(0)` 5) `as` keyword, for example `t.tupleAt(0) as int` 6) methods binding is done along with type inferring, not before ("before", as worked previously, was always a wrong approach)
2024-12-30 15:31:27 +00:00
for (const FunctionData* fun_ref : G.all_functions) {
[Tolk] AST-based semantic analysis, get rid of Expr This is a huge refactoring focusing on untangling compiler internals (previously forked from FunC). The goal is to convert AST directly to Op (a kind of IR representation), doing all code analysis at AST level. Noteable changes: - AST-based semantic kernel includes: registering global symbols, scope handling and resolving local/global identifiers, lvalue/rvalue calc and check, implicit return detection, mutability analysis, pure/impure validity checks, simple constant folding - values of `const` variables are calculated NOT based on CodeBlob, but via a newly-introduced AST-based constant evaluator - AST vertices are now inherited from expression/statement/other; expression vertices have common properties (TypeExpr, lvalue/rvalue) - symbol table is rewritten completely, SymDef/SymVal no longer exist, lexer now doesn't need to register identifiers - AST vertices have references to symbols, filled at different stages of pipeline - the remaining "FunC legacy part" is almost unchanged besides Expr which was fully dropped; AST is converted to Ops (IR) directly
2024-12-16 18:19:45 +00:00
if (fun_ref->is_method_id_not_empty()) { // get methods, main and other entrypoints, regular functions with @method_id
mark_function_used(fun_ref);
[Tolk] Compilation pipeline, register global symbols in advance Since I've implemented AST, now I can drop forward declarations. Instead, I traverse AST of all files and register global symbols (functions, constants, global vars) as a separate step, in advance. That's why, while converting AST to Expr/Op, all available symbols are already registered. This greatly simplifies "intermediate state" of yet unknown functions and checking them afterward. Redeclaration of local variables (inside the same scope) is now also prohibited.
2024-10-31 07:04:58 +00:00
}
}
}
} // namespace tolk
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