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abg-reader: optimize if construction
In 'build_enum_type_decl' function of 'src/abg-reader.cc', the 'for loop' walk through all the child nodes of the '<enum-decl>' for seeking '<underlying-type>' and '<enumerator>': /* original src/abg-reader.cc begin */ static enum_type_decl_sptr build_enum_type_decl(read_context& ctxt, const xmlNodePtr node, bool add_to_current_scope) { ... for (xmlNodePtr n = xmlFirstElementChild(node); n; n = xmlNextElementSibling(n)) { if (xmlStrEqual(n->name, BAD_CAST("underlying-type"))) { ... } if (xmlStrEqual(n->name, BAD_CAST("enumerator"))) { ... } } ... } /* original src/abg-reader.cc end */ Here uses 2 separate 'if' statements for seeking, that is, for any child node of the '<enum-decl>', there involves 2 'if' comparations. Because the child node of the '<enum-decl>' is either '<underlying-type>' or '<enumerator>', there would be a slight optimization when use 'if-else if' construction instead, like below: /* optimized src/abg-reader.cc begin */ for (xmlNodePtr n = xmlFirstElementChild(node); n; n = xmlNextElementSibling(n)) { if (xmlStrEqual(n->name, BAD_CAST("underlying-type"))) { ... } else if (xmlStrEqual(n->name, BAD_CAST("enumerator"))) { ... } } /* optimized src/abg-reader.cc end */ Supposing there has the test case: /* test case begin */ <abi-instr version='1.0'> <enum-decl name='E' filepath='../../abitests/test-enum0-v0.cc' line='1' column='6' id='type-id-2'> <underlying-type type-id='type-id-1'/> <enumerator name='e0' value='0'/> <enumerator name='e2' value='1'/> </enum-decl> </abi-instr> /* test case end */ When parsing the '<underlying-type>' xml tag, for the original 'src/abg-reader.cc', there involves 2 'if' comparations. But involves only 1 'if' comparation for the optimized 'src/abg-reader.cc'. Signed-off-by: Xiaole He <hexiaole@kylinos.cn> Tested-by: Xiaole He <hexiaole@kylinos.cn> Signed-off-by: Dodji Seketeli <dodji@redhat.com>
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@ -4602,8 +4602,7 @@ build_enum_type_decl(read_context& ctxt,
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base_type_id = CHAR_STR(a);
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continue;
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}
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if (xmlStrEqual(n->name, BAD_CAST("enumerator")))
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else if (xmlStrEqual(n->name, BAD_CAST("enumerator")))
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{
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string name;
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int64_t value = 0;
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