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Diffstat (limited to 'contrib/perl5/ext/B/ramblings/cc.notes')
| -rw-r--r-- | contrib/perl5/ext/B/ramblings/cc.notes | 32 |
1 files changed, 32 insertions, 0 deletions
diff --git a/contrib/perl5/ext/B/ramblings/cc.notes b/contrib/perl5/ext/B/ramblings/cc.notes new file mode 100644 index 0000000..47bd65a --- /dev/null +++ b/contrib/perl5/ext/B/ramblings/cc.notes @@ -0,0 +1,32 @@ +At entry to each basic block, the following can be assumed (and hence +must be forced where necessary at the end of each basic block): + +The shadow stack @stack is empty. +For each lexical object in @pad, VALID_IV holds for each T_INT, +VALID_DOUBLE holds for each T_DOUBLE and VALID_SV holds otherwise. +The C shadow variable sp holds the stack pointer (not necessarily stack_sp). + +write_back_stack + Writes the contents of the shadow stack @stack back to the real stack. + A write-back of each object in the stack is forced so that its + backing SV contains the right value and that SV is then pushed onto the + real stack. On return, @stack is empty. + +write_back_lexicals + Forces a write-back (i.e. achieves VALID_SV), where necessary, for each + lexical object in @pad. Objects with the TEMPORARY flag are skipped. If + write_back_lexicals is called with an (optional) argument, then it is + taken to be a bitmask of more flags: any lexical object with one of those + flags set is also skipped and not written back to its SV. + +invalidate_lexicals($avoid) + The VALID_INT and VALID_DOUBLE flags are turned off for each lexical + object in @pad whose flags field doesn't overlap with $avoid. + +reload_lexicals + For each necessary lexical object in @pad, makes sure that VALID_IV + holds for objects of type T_INT, VALID_DOUBLE holds for objects for + type T_DOUBLE, and VALID_SV holds for other objects. An object is + considered for reloading if its flags field does not overlap with the + (optional) argument passed to reload_lexicals. + |
