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#ifndef PHC_HSSA
#define PHC_HSSA
class CFG;
class SSA_name;
class Basic_block;
class Whole_program;
#include "process_ir/General.h"
class HSSA : virtual public GC_obj
{
protected:
Whole_program* wp;
CFG* cfg;
bool check_ssi;
/*
* Following the example of GCC, we give each SSA_NAME a distinct number.
* So instead of x_0, y_0, x_1, y_1, as in textbooks, we use x_0, y_1, x_2,
* y_3. This allows us to use the version as an index into a bitvector (which
* we may or may not do in the future).
*/
int counter;
Map<std::string, Stack<int> > var_stacks;
public:
HSSA(Whole_program* wp, CFG* cfg);
void convert_to_hssa_form ();
void convert_out_of_hssa_form ();
protected:
/*
* Generic interface to insert nodes. SSA will insert phi nodes, while SSI
* variants will insert both phi and sigma nodes.
*/
virtual void insert_nodes ();
/*
* Insertion of phi nodes.
*/
bool insert_phi_nodes();
/*
* Renaming (Cooper/Torczon, section 9.3.4).
* Given a BB, this will perform recursively perform SSA renaming,
* descending the dominator tree. COUNTER is the version of the next
* SSA_NAME. VAR_STACKS is the stack of versions used by a named variable.
* When returning from recursing, the stack is popped to reveal the version
* used on the previous level.
*/
void rename_vars (Basic_block* bb);
void push_to_var_stack (SSA_name* name);
int read_var_stack (SSA_name* name);
void pop_var_stack (SSA_name* name);
// Rename the variable into SSA, giving it a version.
void create_new_ssa_name (SSA_name* name);
void debug_top_var_stack (SSA_name* var, std::string type);
};
#endif // PHC_HSSA
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