Data Fields | |
| tree | addr |
| basic_block | entry_block |
| gimple_vec | stmts |
| tree | save_var |
Detailed Description
Instead of instrumenting thread private memory, we save the addresses in a log which we later use to save/restore the addresses upon transaction start/restart.
The log is keyed by address, where each element contains individual statements among different code paths that perform the store.
This log is later used to generate either plain save/restore of the addresses upon transaction start/restart, or calls to the ITM_L* logging functions.
So for something like:
struct large { int x[1000]; };
struct large lala = { 0 };
__transaction {
lala.x[i] = 123;
...
}
We can either save/restore:
lala = { 0 };
trxn = _ITM_startTransaction ();
if (trxn & a_saveLiveVariables)
tmp_lala1 = lala.x[i];
else if (a & a_restoreLiveVariables)
lala.x[i] = tmp_lala1;
or use the logging functions:
lala = { 0 };
trxn = _ITM_startTransaction ();
_ITM_LU4 (&lala.x[i]);
Obviously, if we use _ITM_L* to log, we prefer to call _ITM_L* as far up the dominator tree to shadow all of the writes to a given location (thus reducing the total number of logging calls), but not so high as to be called on a path that does not perform a write. One individual log entry. We may have multiple statements for the same location if neither dominate each other (on different execution paths).
Field Documentation
| tree tm_log_entry::addr |
Address to save.
Referenced by make_pass_diagnose_tm_blocks(), tm_log_emit(), tm_log_emit_stmt(), and tm_log_init().
| basic_block tm_log_entry::entry_block |
Entry block for the transaction this address occurs in.
Referenced by make_pass_diagnose_tm_blocks(), and tm_log_emit().
| tree tm_log_entry::save_var |
Initially, while we are building the log, we place a nonzero value here to mean that this address will be saved with a save/restore sequence. Later, when generating the save sequence we place the SSA temp generated here.
Referenced by make_pass_diagnose_tm_blocks(), and tm_log_emit().
| gimple_vec tm_log_entry::stmts |
Dominating statements the store occurs in.
Referenced by make_pass_diagnose_tm_blocks().
The documentation for this struct was generated from the following file:
