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C-Breeze C Compiler Infrastructure [ Project home page] |
constantFoldingChanger Class Reference
[phases defined in c-breeze (some of which are available from the command line).]
Folds constants in binary expressions.
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#include <constprop.h>
Inheritance diagram for constantFoldingChanger:
"at_" methods | |
| These methods define the functions that should be performed when different classes of Nodes are encountered in the AST. The most specific "at_" method that matches a given Node's class will be called. | |
| virtual Node * | at_node (Node *the_node, Order ord) |
| virtual Node * | at_unit (unitNode *the_unit, Order ord) |
| virtual Node * | at_def (defNode *the_def, Order ord) |
| virtual Node * | at_decl (declNode *the_decl, Order ord) |
| virtual Node * | at_subdecl (subdeclNode *the_subdecl, Order ord) |
| virtual Node * | at_proc (procNode *the_proc, Order ord) |
| virtual Node * | at_type (typeNode *the_type, Order ord) |
| virtual Node * | at_prim (primNode *the_prim, Order ord) |
| virtual Node * | at_tdef (tdefNode *the_tdef, Order ord) |
| virtual Node * | at_ptr (ptrNode *the_ptr, Order ord) |
| virtual Node * | at_array (arrayNode *the_array, Order ord) |
| virtual Node * | at_func (funcNode *the_func, Order ord) |
| virtual Node * | at_sue (sueNode *the_sue, Order ord) |
| virtual Node * | at_struct (structNode *the_struct, Order ord) |
| virtual Node * | at_union (unionNode *the_union, Order ord) |
| virtual Node * | at_enum (enumNode *the_enum, Order ord) |
| virtual Node * | at_suespec (suespecNode *the_suespec, Order ord) |
| virtual Node * | at_expr (exprNode *the_expr, Order ord) |
| virtual Node * | at_index (indexNode *the_index, Order ord) |
| virtual Node * | at_const (constNode *the_const, Order ord) |
| virtual Node * | at_id (idNode *the_id, Order ord) |
| virtual Node * | at_binary (binaryNode *the_binary, Order ord) |
| virtual Node * | at_unary (unaryNode *the_unary, Order ord) |
| virtual Node * | at_cast (castNode *the_cast, Order ord) |
| virtual Node * | at_comma (commaNode *the_comma, Order ord) |
| virtual Node * | at_ternary (ternaryNode *the_ternary, Order ord) |
| virtual Node * | at_call (callNode *the_call, Order ord) |
| virtual Node * | at_initializer (initializerNode *the_initializer, Order ord) |
| virtual Node * | at_stmt (stmtNode *the_stmt, Order ord) |
| virtual Node * | at_block (blockNode *the_block, Order ord) |
| virtual Node * | at_exprstmt (exprstmtNode *the_exprstmt, Order ord) |
| virtual Node * | at_target (targetNode *the_target, Order ord) |
| virtual Node * | at_label (labelNode *the_label, Order ord) |
| virtual Node * | at_case (caseNode *the_case, Order ord) |
| virtual Node * | at_selection (selectionNode *the_selection, Order ord) |
| virtual Node * | at_if (ifNode *the_if, Order ord) |
| virtual Node * | at_switch (switchNode *the_switch, Order ord) |
| virtual Node * | at_loop (loopNode *the_loop, Order ord) |
| virtual Node * | at_while (whileNode *the_while, Order ord) |
| virtual Node * | at_do (doNode *the_do, Order ord) |
| virtual Node * | at_for (forNode *the_for, Order ord) |
| virtual Node * | at_jump (jumpNode *the_jump, Order ord) |
| virtual Node * | at_goto (gotoNode *the_goto, Order ord) |
| virtual Node * | at_continue (continueNode *the_continue, Order ord) |
| virtual Node * | at_break (breakNode *the_break, Order ord) |
| virtual Node * | at_return (returnNode *the_return, Order ord) |
| virtual Node * | at_attrib (attribNode *the_attrib, Order ord) |
| virtual Node * | at_operand (operandNode *the_oper, Order ord) |
| virtual Node * | at_text (textNode *the_text, Order ord) |
Public Types | |
| enum | Order { Preorder, Postorder, Both } |
| enum | Depth { Subtree, NodeOnly } |
Static Public Member Functions | |
| void | change () |
| Constant propagation on entire program. | |
| void | change (unitNode *) |
| Constant propagation on one unit. | |
| void | change (procNode *) |
| Constant propagation on one procedure. | |
Private Member Functions | |
| constantFoldingChanger () | |
| void | reset () |
| Reset the _changed flag. | |
| Node * | at_threeAddr (threeAddrNode *, Order) |
| Performs constant folding on an threeAddrNode. | |
| Node * | at_conditiongoto (conditiongotoNode *, Order) |
| Node * | at_basicblock (basicblockNode *, Order) |
Private Attributes | |
| bool | _changed |
| Flag to indicate if any code is changed by this optimization. | |
| bool | _cfg_changed |
| Flag to indicate if cfg is changed by this optimization. | |
| basicblockNode * | _current_block |
| Current basic block. | |
Friends | |
| class | constantPropChanger |
Detailed Description
Folds constants in binary expressions.This class performs the constant folding. The program must already be dismantled. The three public static change() functions allow the optimization to be performed on the entire program, on one unit, or on a single procedure. The ud chain of the relevant part of the program must be provided.
Constant folding is performed at threeAddrNode's and conditiongotoNode's. At a threeAddrNode, if there are two right-hand-side constants, they are folded into one. At a conditiongotoNode, if the two operands are constants, the value of the condition is evaluated. If the value is non-zero, the conditiongotoNode is replaced with a goto to the true branch; otherwise, the conditiongotoNode is eliminated.
As a result of constant folding on conditions, some branches may become unreachable code. The cfg phase can be used to eliminate the dead code.
Definition at line 112 of file constprop.h.
Member Enumeration Documentation
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Constructor & Destructor Documentation
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Definition at line 126 of file constprop.h. References _cfg_changed, _changed, _current_block, Changer::Preorder, and Changer::Subtree. |
Member Function Documentation
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Reimplemented in AllocSizeChanger. Definition at line 253 of file changer.h. References Changer::at_type(). Referenced by arrayNode::change(). |
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Definition at line 364 of file changer.h. References Changer::at_stmt(). Referenced by attribNode::change(). |
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Reimplemented from Changer. Definition at line 335 of file constprop.cc. References _current_block. |
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Reimplemented in SelectionDismantle, ArrowDismantle, and ExpressionDismantle. Definition at line 286 of file changer.h. References Changer::at_expr(). Referenced by binaryNode::change(). |
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Reimplemented in StaticToGlobalDismantle, and InitializerDismantle. Definition at line 310 of file changer.h. References Changer::at_stmt(). Referenced by Changer::at_basicblock(), and blockNode::change(). |
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Reimplemented in BreakContinueChanger. Definition at line 358 of file changer.h. References Changer::at_jump(). Referenced by breakNode::change(). |
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Reimplemented in ExpressionDismantle. Definition at line 301 of file changer.h. References Changer::at_expr(). Referenced by callNode::change(). |
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Definition at line 325 of file changer.h. References Changer::at_target(). Referenced by caseNode::change(). |
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Reimplemented in ExpressionDismantle, and CastRemover. Definition at line 292 of file changer.h. References Changer::at_expr(). Referenced by castNode::change(). |
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Reimplemented in ExpressionDismantle. Definition at line 295 of file changer.h. References Changer::at_expr(). Referenced by commaNode::change(). |
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Reimplemented from Changer. Definition at line 341 of file constprop.cc. References _cfg_changed, _changed, _current_block, basicblock_list, basicblock_list_p, constant::Boolean(), Const, constant::eval(), gotoNode::label(), conditiongotoNode::left(), constant::no_val(), conditiongotoNode::op(), conditiongotoNode::right(), basicblockNode::succs(), Node::typ(), and exprNode::value(). |
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Definition at line 280 of file changer.h. References Changer::at_index(). Referenced by constNode::change(). |
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Reimplemented in BreakContinueChanger. Definition at line 355 of file changer.h. References Changer::at_jump(). Referenced by continueNode::change(). |
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Reimplemented in AllocSizeChanger, StaticToGlobalDismantle, InitializerDismantle, FlattenDismantle, ref_clone_changer, and TreeFixer. Definition at line 232 of file changer.h. References Changer::at_def(). Referenced by Changer::at_subdecl(), and declNode::change(). |
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Definition at line 229 of file changer.h. References Changer::at_node(). Referenced by Changer::at_decl(), and Changer::at_proc(). |
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Reimplemented in LoopDismantle. Definition at line 343 of file changer.h. References Changer::at_loop(). Referenced by doNode::change(). |
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Reimplemented in AllocSizeChanger. Definition at line 268 of file changer.h. References Changer::at_sue(). Referenced by enumNode::change(). |
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Reimplemented in ipConstantsChanger. Definition at line 274 of file changer.h. References Changer::at_node(). Referenced by Changer::at_binary(), Changer::at_call(), Changer::at_cast(), Changer::at_comma(), Changer::at_index(), Changer::at_initializer(), Changer::at_operand(), Changer::at_ternary(), Changer::at_unary(), and metaexprNode::change(). |
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Reimplemented in SelectionDismantle, ExpressionDismantle, and FlattenDismantle. Definition at line 316 of file changer.h. References Changer::at_stmt(). Referenced by exprstmtNode::change(). |
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Reimplemented in LoopDismantle. Definition at line 346 of file changer.h. References Changer::at_loop(). Referenced by forNode::change(). |
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Definition at line 256 of file changer.h. References Changer::at_type(). Referenced by funcNode::change(). |
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Reimplemented in FlattenDismantle. Definition at line 352 of file changer.h. References Changer::at_jump(). Referenced by Changer::at_conditiongoto(), and gotoNode::change(). |
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Reimplemented in UnusedDeclarationCleanupChanger, and constantsChanger. Definition at line 283 of file changer.h. References Changer::at_index(). Referenced by idNode::change(). |
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Reimplemented in SelectionDismantle, and CFS_Changer. Definition at line 331 of file changer.h. References Changer::at_selection(). Referenced by ifNode::change(). |
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Definition at line 277 of file changer.h. References Changer::at_expr(). Referenced by Changer::at_const(), and Changer::at_id(). |
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Definition at line 304 of file changer.h. References Changer::at_expr(). Referenced by initializerNode::change(). |
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Definition at line 349 of file changer.h. References Changer::at_stmt(). Referenced by Changer::at_break(), Changer::at_continue(), Changer::at_goto(), and Changer::at_return(). |
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Reimplemented in LabelDismantle, FlattenDismantle, and ref_clone_changer. Definition at line 322 of file changer.h. References Changer::at_target(). Referenced by labelNode::change(). |
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Definition at line 337 of file changer.h. References Changer::at_stmt(). Referenced by Changer::at_do(), Changer::at_for(), and Changer::at_while(). |
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Reimplemented in ref_clone_changer. Definition at line 223 of file changer.h. Referenced by Changer::at_def(), Changer::at_expr(), Changer::at_stmt(), Changer::at_text(), Changer::at_type(), and Changer::at_unit(). |
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Definition at line 367 of file changer.h. References Changer::at_expr(). Referenced by operandNode::change(). |
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Reimplemented in AllocSizeChanger. Definition at line 244 of file changer.h. References Changer::at_type(). Referenced by primNode::change(). |
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Reimplemented in Dismantle, StaticToGlobalDismantle, ControlDismantle, ReturnDismantle, FlattenDismantle, function_inline, cfg_changer, copyPropChanger, deadCodeEliminationChanger, UnusedDeclarationCleanupChanger, LocalCopyPropChanger, CFS_Changer, and Optimizer. Definition at line 238 of file changer.h. References Changer::at_def(). Referenced by procNode::change(). |
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Reimplemented in AllocSizeChanger. Definition at line 250 of file changer.h. References Changer::at_type(). Referenced by ptrNode::change(). |
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Reimplemented in SelectionDismantle, ReturnDismantle, FlattenDismantle, and constantPropChanger. Definition at line 361 of file changer.h. References Changer::at_jump(). Referenced by returnNode::change(). |
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Definition at line 328 of file changer.h. References Changer::at_stmt(). Referenced by Changer::at_if(), and Changer::at_switch(). |
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Reimplemented in TernaryDismantle, and SelectionDismantle. Definition at line 307 of file changer.h. References Changer::at_node(). Referenced by Changer::at_attrib(), Changer::at_block(), Changer::at_exprstmt(), Changer::at_jump(), Changer::at_loop(), Changer::at_selection(), Changer::at_target(), Changer::at_threeAddr(), and metastmtNode::change(). |
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Reimplemented in AllocSizeChanger. Definition at line 262 of file changer.h. References Changer::at_sue(). Referenced by structNode::change(). |
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Definition at line 235 of file changer.h. References Changer::at_decl(). Referenced by subdeclNode::change(). |
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Definition at line 259 of file changer.h. References Changer::at_type(). Referenced by Changer::at_enum(), Changer::at_struct(), and Changer::at_union(). |
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Definition at line 271 of file changer.h. References Changer::at_type(). Referenced by suespecNode::change(). |
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Reimplemented in SelectionDismantle, and ref_clone_changer. Definition at line 334 of file changer.h. References Changer::at_selection(). Referenced by switchNode::change(). |
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Definition at line 319 of file changer.h. References Changer::at_stmt(). Referenced by Changer::at_case(), and Changer::at_label(). |
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Reimplemented in AllocSizeChanger, and UpdateTdefChanger. Definition at line 247 of file changer.h. References Changer::at_type(). Referenced by tdefNode::change(). |
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Reimplemented in TernaryDismantle. Definition at line 298 of file changer.h. References Changer::at_expr(). Referenced by ternaryNode::change(). |
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Definition at line 376 of file changer.h. References Changer::at_node(). Referenced by textNode::change(). |
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Performs constant folding on an threeAddrNode.
Reimplemented from Changer. Definition at line 212 of file constprop.cc. References _changed, operandNode::addr(), constant::basic(), Const, Operator::EQ, constant::eval(), operandNode::fields(), Operator::GE, operandNode::index(), constant::Integer(), constant::is_zero(), Operator::LE, Operator::LS, Operator::NE, constant::no_val(), threeAddrNode::op(), threeAddrNode::rhs1(), threeAddrNode::rhs2(), Operator::RS, operandNode::star(), Operator::UMINUS, Operator::UPLUS, exprNode::value(), and operandNode::var(). |
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Reimplemented in TernaryDismantle, and ExpressionDismantle. Definition at line 241 of file changer.h. References Changer::at_node(). Referenced by Changer::at_array(), Changer::at_func(), Changer::at_prim(), Changer::at_ptr(), Changer::at_sue(), Changer::at_suespec(), and Changer::at_tdef(). |
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Reimplemented in AllocSizeChanger, and ExpressionDismantle. Definition at line 289 of file changer.h. References Changer::at_expr(). Referenced by unaryNode::change(). |
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Reimplemented in AllocSizeChanger. Definition at line 265 of file changer.h. References Changer::at_sue(). Referenced by unionNode::change(). |
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Reimplemented in Dismantle, StaticToGlobalDismantle, and Optimizer. Definition at line 226 of file changer.h. References Changer::at_node(). Referenced by unitNode::change(). |
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Reimplemented in LoopDismantle. Definition at line 340 of file changer.h. References Changer::at_loop(). Referenced by whileNode::change(). |
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Constant propagation on one procedure.
Definition at line 476 of file constprop.cc. References procNode::change(). |
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Constant propagation on one unit.
Definition at line 470 of file constprop.cc. References change(), def_list_p, unitNode::defs(), and Proc. |
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Constant propagation on entire program.
Definition at line 465 of file constprop.cc. References CBZ::Program, and unit_list_p. Referenced by change(). |
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Return whether this Changer deletes Nodes which are removed from the AST by "at_" methods.
Definition at line 209 of file changer.h. Referenced by subdeclNode::change(), change_list(), and Changer::Changer(). |
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Return which Nodes of an AST should be visited. A value of SubTree specifies that the entire AST should be traversed. A value of NodeOnly specifies that only the root Node in the AST should be visited. |
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Reset the _changed flag.
Definition at line 131 of file constprop.h. References _cfg_changed, and _changed. Referenced by constantPropChanger::change(). |
Friends And Related Function Documentation
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Definition at line 113 of file constprop.h. |
Member Data Documentation
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Flag to indicate if cfg is changed by this optimization.
Definition at line 137 of file constprop.h. Referenced by at_conditiongoto(), constantPropChanger::change(), constantFoldingChanger(), and reset(). |
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Flag to indicate if any code is changed by this optimization.
Definition at line 134 of file constprop.h. Referenced by at_conditiongoto(), at_threeAddr(), constantPropChanger::change(), constantFoldingChanger(), and reset(). |
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Current basic block.
Definition at line 140 of file constprop.h. Referenced by at_basicblock(), at_conditiongoto(), and constantFoldingChanger(). |
The documentation for this class was generated from the following files: