Viewing file:  Lower_expr_flow.cpp (1.92 KB) -rw-rw-r--
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/*
* phc -- the open source PHP compiler
* See doc/license/README.license for licensing information
*
* Lower control flow inside expressions (",", "&&", "||", "?:")
*/
#include "Lower_expr_flow.h"
#include "process_ir/General.h"
using namespace AST;
/*
* Binary operator
*
* Convert
* foo(f(), g());
* into
* f();
* foo(g());
*
* Convert
* foo(f() || g());
* into
* $TEF1 = f();
* foo((bool)($TEF1 ? $TEF1 : g()));
*
* Convert
* foo(f() && g());
* into
* $TEF1 = f();
* foo((bool)($TEF1 ? g() : $TEF1));
*
* The conditional expressions are then taken care of by post_conditional_expr
*/
Expr* Lower_expr_flow::post_bin_op(Bin_op* in)
{
Conditional_expr* result;
if(*in->op->value == ",")
{
pieces->push_back(new Eval_expr(in->left));
return in->right;
}
else if(*in->op->value == "||" || *in->op->value == "or")
{
Variable* temp = dynamic_cast<Variable*>(eval(in->left));
assert(temp);
result = new Conditional_expr(
temp->clone(),
temp->clone(),
in->right);
}
else if(*in->op->value == "&&" || *in->op->value == "and")
{
Variable* temp = dynamic_cast<Variable*>(eval(in->left));
assert(temp);
result = new Conditional_expr (
temp->clone(),
in->right,
temp->clone());
}
else
return in;
// && and || automatically turn their parameters into bools
return new Cast (new CAST (s("bool")), post_conditional_expr (result));
}
/*
* Translate
* foo(f() ? g() : h());
* into
* if(f()) $TEF2 = g ();
* else $TEF2 = h ();
* foo($TEF2);
*/
Expr* Lower_expr_flow::post_conditional_expr(Conditional_expr* in)
{
Variable* temp = fresh_var("TEF");
pieces->push_back(new If (
in->cond,
new Statement_list (
new Eval_expr (
new Assignment (
temp->clone (),
false,
in->iftrue))),
new Statement_list (
new Eval_expr (
new Assignment (
temp->clone (),
false,
in->iffalse)))));
return temp;
}
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