diff options
Diffstat (limited to 'gcc/ipa-prop.h')
| -rw-r--r-- | gcc/ipa-prop.h | 77 |
1 files changed, 48 insertions, 29 deletions
diff --git a/gcc/ipa-prop.h b/gcc/ipa-prop.h index 5a293d9..0f9b5f3 100644 --- a/gcc/ipa-prop.h +++ b/gcc/ipa-prop.h @@ -39,38 +39,40 @@ along with GCC; see the file COPYING3. If not see argument. Unknown - neither of the above. - IPA_JF_CONST_MEMBER_PTR stands for C++ member pointers, other constants are - represented with IPA_JF_CONST. + IPA_JF_CONST_MEMBER_PTR stands for C++ member pointers, it is a special + constant in this regard. Other constants are represented with IPA_JF_CONST. + + IPA_JF_ANCESTOR is a special pass-through jump function, which means that + the result is an address of a part of the object pointed to by the formal + parameter to which the function refers. It is mainly intended to represent + getting addresses of of ancestor fields in C++ + (e.g. &this_1(D)->D.1766.D.1756). Note that if the original pointer is + NULL, ancestor jump function must behave like a simple pass-through. + + Other pass-through functions can either simply pass on an unchanged formal + parameter or can apply one simple binary operation to it (such jump + functions are called polynomial). + + IPA_JF_KNOWN_TYPE is a special type of an "unknown" function that applies + only to pointer parameters. It means that even though we cannot prove that + the passed value is an interprocedural constant, we still know the exact + type of the containing object which may be valuable for devirtualization. + + Jump functions are computed in ipa-prop.c by function + update_call_notes_after_inlining. Some information can be lost and jump + functions degraded accordingly when inlining, see + update_call_notes_after_inlining in the same file. */ - In addition to "ordinary" pass through functions represented by - IPA_JF_PASS_THROUGH, IPA_JF_ANCESTOR represents getting addresses of of - ancestor fields in C++ (e.g. &this_1(D)->D.1766.D.1756). */ enum jump_func_type { IPA_JF_UNKNOWN = 0, /* newly allocated and zeroed jump functions default */ - IPA_JF_CONST, - IPA_JF_CONST_MEMBER_PTR, - IPA_JF_PASS_THROUGH, - IPA_JF_ANCESTOR + IPA_JF_KNOWN_TYPE, /* represented by field base_binfo */ + IPA_JF_CONST, /* represented by field costant */ + IPA_JF_CONST_MEMBER_PTR, /* represented by field member_cst */ + IPA_JF_PASS_THROUGH, /* represented by field pass_through */ + IPA_JF_ANCESTOR /* represented by field ancestor */ }; -/* All formal parameters in the program have a lattice associated with it - computed by the interprocedural stage of IPCP. - There are three main values of the lattice: - IPA_TOP - unknown, - IPA_BOTTOM - non constant, - IPA_CONST_VALUE - simple scalar constant, - Cval of formal f will have a constant value if all callsites to this - function have the same constant value passed to f. - Integer and real constants are represented as IPA_CONST_VALUE. */ -enum ipa_lattice_type -{ - IPA_BOTTOM, - IPA_CONST_VALUE, - IPA_TOP -}; - - /* Structure holding data required to describe a pass-through jump function. */ struct GTY(()) ipa_pass_through_data @@ -87,8 +89,8 @@ struct GTY(()) ipa_pass_through_data enum tree_code operation; }; -/* Structure holding data required to describe and ancestor pass throu - funkci. */ +/* Structure holding data required to describe an ancestor pass-through + jump function. */ struct GTY(()) ipa_ancestor_jf_data { @@ -119,13 +121,30 @@ struct GTY (()) ipa_jump_func functions and member_cst holds constant c++ member functions. */ union jump_func_value { + tree GTY ((tag ("IPA_JF_KNOWN_TYPE"))) base_binfo; tree GTY ((tag ("IPA_JF_CONST"))) constant; + struct ipa_member_ptr_cst GTY ((tag ("IPA_JF_CONST_MEMBER_PTR"))) member_cst; struct ipa_pass_through_data GTY ((tag ("IPA_JF_PASS_THROUGH"))) pass_through; struct ipa_ancestor_jf_data GTY ((tag ("IPA_JF_ANCESTOR"))) ancestor; - struct ipa_member_ptr_cst GTY ((tag ("IPA_JF_CONST_MEMBER_PTR"))) member_cst; } GTY ((desc ("%1.type"))) value; }; +/* All formal parameters in the program have a lattice associated with it + computed by the interprocedural stage of IPCP. + There are three main values of the lattice: + IPA_TOP - unknown, + IPA_BOTTOM - non constant, + IPA_CONST_VALUE - simple scalar constant, + Cval of formal f will have a constant value if all callsites to this + function have the same constant value passed to f. + Integer and real constants are represented as IPA_CONST_VALUE. */ +enum ipa_lattice_type +{ + IPA_BOTTOM, + IPA_CONST_VALUE, + IPA_TOP +}; + /* All formal parameters in the program have a cval computed by the interprocedural stage of IPCP. See enum ipa_lattice_type for the various types of lattices supported */ |