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https://github.com/Zenithsiz/ftmemsim-valgrind.git
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This optimisation divides by 2.5 the time (user+sys) needed to read
the inlined info of a big executable. On a slow pentium, reading the inline info now takes 5.5 seconds. The optimisation consists in having per dw3 abbreviation a structure allowing to skip efficiently the non interesting DIEs (i.e. the DIEs the parse_inl_DIE is not interested in). Mostly, the idea is to avoid calling the image abstraction, and replace this by just advancing the cursor (i.e. addition rather than a bunch of function calls to read the data). git-svn-id: svn://svn.valgrind.org/valgrind/trunk@14075
This commit is contained in:
Philippe Waroquiers
parent
083986d244
commit
cdfd3be6b7
@ -217,6 +217,10 @@ static inline void set_position_of_Cursor ( Cursor* c, ULong pos ) {
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c->sli_next = c->sli.ioff + pos;
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vg_assert(is_sane_Cursor(c));
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}
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static inline void advance_position_of_Cursor ( Cursor* c, ULong delta ) {
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c->sli_next += delta;
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vg_assert(is_sane_Cursor(c));
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}
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static /*signed*/Long get_remaining_length_Cursor ( Cursor* c ) {
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vg_assert(is_sane_Cursor(c));
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@ -380,9 +384,24 @@ static ULong get_Initial_Length ( /*OUT*/Bool* is64,
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typedef
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struct _name_form {
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ULong at_name;
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ULong at_form;
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ULong at_name; // Dwarf Attribute name
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ULong at_form; // Dward Attribute form
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UInt skip_szB; // Nr of bytes skippable from here ...
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UInt next_nf; // ... to reach this attr/form index in the g_abbv.nf
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} name_form;
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/* skip_szB and n_nf are used to optimise the skipping of uninteresting DIEs.
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Each name_form maintains how many (fixed) nr of bytes can be skipped from
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the beginning of this form till the next attr/form to look at.
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The next form to look can be:
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an 'interesting' attr/form to read while skipping a DIE
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(currently, this is only DW_AT_sibling)
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or
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a variable length form which must be read to be skipped.
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For a variable length form, the skip_szB will be equal to VARSZ_FORM.
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Note: this technique could also be used to speed up the parsing
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of DIEs : for each parser kind, we could have the nr of bytes
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to skip to directly reach the interesting form(s) for the parser. */
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typedef
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struct _g_abbv {
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@ -392,7 +411,9 @@ typedef
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ULong has_children;
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name_form nf[0];
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/* Variable-length array of name/form pairs, terminated
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by a 0/0 pair. */
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by a 0/0 pair.
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The skip_szB/next_nf allows to skip efficiently a DIE
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described by this g_abbv; */
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} g_abbv;
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/* Holds information that is constant through the parsing of a
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@ -865,6 +886,9 @@ static XArray* /* of AddrRange */
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return xa;
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}
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#define VARSZ_FORM 0xffffffff
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static UInt get_Form_szB (CUConst* cc, DW_FORM form );
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/* Initialises the hash table of abbreviations.
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We do a single scan of the abbv slice to parse and
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build all abbreviations, for the following reasons:
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@ -880,7 +904,8 @@ static void init_ht_abbvs (CUConst* cc,
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g_abbv *ta; // temporary abbreviation, reallocated if needed.
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UInt ta_nf_maxE; // max nr of pairs in ta.nf[], doubled when reallocated.
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UInt ta_nf_n; // nr of pairs in ta->nf that are initialised.
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g_abbv *ht_ta; // abbv to insert in hash table.
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g_abbv *ht_ta; // abbv to insert in hash table.
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Int i;
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#define SZ_G_ABBV(_nf_szE) (sizeof(g_abbv) + _nf_szE * sizeof(name_form))
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@ -914,13 +939,42 @@ static void init_ht_abbvs (CUConst* cc,
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}
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ta_nf_n++;
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}
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// Initialises the skip_szB/next_nf elements : an element at position
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// i must contain the sum of its own size + the sizes of all elements
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// following i till either the next variable size element, the next
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// sibling element or the end of the DIE.
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ta->nf[ta_nf_n - 1].skip_szB = 0;
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ta->nf[ta_nf_n - 1].next_nf = 0;
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for (i = ta_nf_n - 2; i >= 0; i--) {
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const UInt form_szB = get_Form_szB (cc, (DW_FORM)ta->nf[i].at_form);
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if (ta->nf[i+1].at_name == DW_AT_sibling
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|| ta->nf[i+1].skip_szB == VARSZ_FORM) {
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ta->nf[i].skip_szB = form_szB;
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ta->nf[i].next_nf = i+1;
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} else if (form_szB == VARSZ_FORM) {
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ta->nf[i].skip_szB = form_szB;
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ta->nf[i].next_nf = i+1;
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} else {
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ta->nf[i].skip_szB = ta->nf[i+1].skip_szB + form_szB;
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ta->nf[i].next_nf = ta->nf[i+1].next_nf;
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}
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}
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ht_ta = ML_(dinfo_zalloc) ("di.readdwarf3.ht_ta", SZ_G_ABBV(ta_nf_n));
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VG_(memcpy) (ht_ta, ta, SZ_G_ABBV(ta_nf_n));
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VG_(HT_add_node) ( cc->ht_abbvs, ht_ta );
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TRACE_D3(" Adding abbv_code %llu TAG %s [%s] nf %d\n",
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(ULong) ht_ta->abbv_code, ML_(pp_DW_TAG)(ht_ta->atag),
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ML_(pp_DW_children)(ht_ta->has_children),
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ta_nf_n);
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if (TD3) {
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TRACE_D3(" Adding abbv_code %llu TAG %s [%s] nf %d ",
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(ULong) ht_ta->abbv_code, ML_(pp_DW_TAG)(ht_ta->atag),
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ML_(pp_DW_children)(ht_ta->has_children),
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ta_nf_n);
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TRACE_D3(" ");
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for (i = 0; i < ta_nf_n; i++)
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TRACE_D3("[%u,%u] ", ta->nf[i].skip_szB, ta->nf[i].next_nf);
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TRACE_D3("\n");
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}
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}
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ML_(dinfo_free) (ta);
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@ -1082,6 +1136,9 @@ void get_Form_contents ( /*OUT*/FormContents* cts,
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Bool td3, DW_FORM form )
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{
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VG_(bzero_inline)(cts, sizeof(*cts));
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// !!! keep switch in sync with get_Form_szB. The nr of characters read below
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// must be computed similarly in get_Form_szB.
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// The consistency is verified in trace_DIE.
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switch (form) {
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case DW_FORM_data1:
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cts->u.val = (ULong)(UChar)get_UChar(c);
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@ -1372,6 +1429,119 @@ void get_Form_contents ( /*OUT*/FormContents* cts,
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}
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}
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static inline UInt sizeof_Dwarfish_UWord (Bool is_dw64)
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{
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if (is_dw64)
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return sizeof(ULong);
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else
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return sizeof(UInt);
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}
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#define VARSZ_FORM 0xffffffff
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/* If the form is a fixed length form, return the nr of bytes for this form.
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If the form is a variable length form, return VARSZ_FORM. */
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static
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UInt get_Form_szB (CUConst* cc, DW_FORM form )
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{
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// !!! keep switch in sync with get_Form_contents : the nr of bytes
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// read from a cursor by get_Form_contents must be returned by
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// the below switch.
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// The consistency is verified in trace_DIE.
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switch (form) {
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case DW_FORM_data1: return 1;
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case DW_FORM_data2: return 2;
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case DW_FORM_data4: return 4;
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case DW_FORM_data8: return 8;
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case DW_FORM_sec_offset:
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if (cc->is_dw64)
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return 8;
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else
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return 4;
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case DW_FORM_sdata:
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return VARSZ_FORM;
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case DW_FORM_udata:
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return VARSZ_FORM;
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case DW_FORM_addr: // See hack in get_Form_contents
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return sizeof(UWord);
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case DW_FORM_ref_addr: // See hack in get_Form_contents
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if (cc->version == 2)
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return sizeof(UWord);
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else
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return sizeof_Dwarfish_UWord (cc->is_dw64);
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case DW_FORM_strp:
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return sizeof_Dwarfish_UWord (cc->is_dw64);
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case DW_FORM_string:
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return VARSZ_FORM;
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case DW_FORM_ref1:
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return 1;
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case DW_FORM_ref2:
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return 2;
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case DW_FORM_ref4:
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return 4;
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case DW_FORM_ref8:
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return 8;
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case DW_FORM_ref_udata:
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return VARSZ_FORM;
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case DW_FORM_flag:
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return 1;
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case DW_FORM_flag_present:
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return 0; // !!! special case, no data.
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case DW_FORM_block1:
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return VARSZ_FORM;
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case DW_FORM_block2:
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return VARSZ_FORM;
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case DW_FORM_block4:
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return VARSZ_FORM;
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case DW_FORM_exprloc:
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case DW_FORM_block:
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return VARSZ_FORM;
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case DW_FORM_ref_sig8:
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return 8 + 8;
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case DW_FORM_indirect:
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return VARSZ_FORM;
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case DW_FORM_GNU_ref_alt:
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return sizeof_Dwarfish_UWord(cc->is_dw64);
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case DW_FORM_GNU_strp_alt:
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return sizeof_Dwarfish_UWord(cc->is_dw64);
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default:
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VG_(printf)(
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"get_Form_szB: unhandled %d (%s)\n",
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form, ML_(pp_DW_FORM)(form));
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cc->barf("get_Form_contents: unhandled DW_FORM");
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}
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}
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/* Skip a DIE as described by abbv.
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If the DIE has a sibling, *sibling is set to the skipped DIE sibling value. */
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static
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void skip_DIE (UWord *sibling,
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Cursor* c_die,
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g_abbv *abbv,
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CUConst* cc)
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{
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UInt nf_i;
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FormContents cts;
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nf_i = 0;
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while (True) {
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if (abbv->nf[nf_i].at_name == DW_AT_sibling) {
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get_Form_contents( &cts, cc, c_die, False /*td3*/,
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(DW_FORM)abbv->nf[nf_i].at_form );
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if ( cts.szB > 0 )
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*sibling = cts.u.val;
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nf_i++;
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} else if (abbv->nf[nf_i].skip_szB == VARSZ_FORM) {
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get_Form_contents( &cts, cc, c_die, False /*td3*/,
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(DW_FORM)abbv->nf[nf_i].at_form );
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nf_i++;
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} else {
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advance_position_of_Cursor (c_die, (ULong)abbv->nf[nf_i].skip_szB);
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nf_i = abbv->nf[nf_i].next_nf;
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}
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if (nf_i == 0)
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break;
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}
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}
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/*------------------------------------------------------------*/
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/*--- ---*/
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@ -1586,8 +1756,8 @@ void read_filename_table( /*MOD*/XArray* /* of UChar* */ filenameTable,
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"Overrun whilst reading .debug_line section(1)" );
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/* unit_length = */
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get_Initial_Length( &is_dw64, &c,
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"read_filename_table: invalid initial-length field" );
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get_Initial_Length( &is_dw64, &c,
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"read_filename_table: invalid initial-length field" );
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version = get_UShort( &c );
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if (version != 2 && version != 3 && version != 4)
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cc->barf("read_filename_table: Only DWARF version 2, 3 and 4 line info "
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@ -1685,9 +1855,12 @@ static void trace_DIE(
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{
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Cursor c;
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FormContents cts;
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UWord sibling = 0;
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UInt nf_i;
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Bool debug_types_flag;
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Bool alt_flag;
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Cursor check_skip;
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UWord check_sibling = 0;
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posn = uncook_die( cc, posn, &debug_types_flag, &alt_flag );
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init_Cursor (&c,
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@ -1695,6 +1868,7 @@ static void trace_DIE(
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alt_flag ? cc->escn_debug_info_alt : cc->escn_debug_info,
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saved_die_c_offset, cc->barf,
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"Overrun trace_DIE");
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check_skip = c;
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VG_(printf)(" <%d><%lx>: Abbrev Number: %llu (%s)%s%s\n",
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level, posn, (ULong) abbv->abbv_code, ML_(pp_DW_TAG)( dtag ),
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debug_types_flag ? " (in .debug_types)" : "",
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@ -1708,8 +1882,22 @@ static void trace_DIE(
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VG_(printf)(" %18s: ", ML_(pp_DW_AT)(attr));
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/* Get the form contents, so as to print them */
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get_Form_contents( &cts, cc, &c, True, form );
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if (attr == DW_AT_sibling && cts.szB > 0) {
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sibling = cts.u.val;
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}
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VG_(printf)("\t\n");
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}
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/* Verify that skipping a DIE gives the same displacement as
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tracing (i.e. reading) a DIE. If there is an inconsistency in
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the nr of bytes read by get_Form_contents and get_Form_szB, this
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should be detected by the below. Using --trace-symtab=yes
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--read-var-info=yes will ensure all DIEs are systematically
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verified. */
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skip_DIE (&check_sibling, &check_skip, abbv, cc);
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vg_assert (check_sibling == sibling);
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vg_assert (get_position_of_Cursor (&check_skip)
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== get_position_of_Cursor (&c));
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}
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__attribute__((noreturn))
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@ -3823,26 +4011,11 @@ static void read_DIE (
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// DIE was read by a parser above, so we know where the DIE ends.
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set_position_of_Cursor( c, after_die_c_offset );
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} else {
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/* No parser has parsed this DIE. So, we need to read the DIE
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to skip its data, in order to read the next DIE.
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/* No parser has parsed this DIE. So, we need to skip the DIE,
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in order to read the next DIE.
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At the same time, establish sibling value if the DIE has one. */
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UInt nf_i;
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TRACE_D3(" (skipped DIE)\n");
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nf_i = 0;
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while (True) {
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FormContents cts;
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ULong at_name = abbv->nf[nf_i].at_name;
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ULong at_form = abbv->nf[nf_i].at_form;
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nf_i++;
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if (at_name == 0 && at_form == 0) break;
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/* Get the form contents, but ignore them; the only purpose is
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to skip the data or get the DIE sibling, if it has one. */
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get_Form_contents( &cts, cc, c, False /*td3*/, (DW_FORM)at_form );
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if (UNLIKELY(at_name == DW_AT_sibling && cts.szB > 0)) {
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sibling = cts.u.val;
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}
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}
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TRACE_D3(" uninteresting DIE -> skipping ...\n");
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skip_DIE (&sibling, c, abbv, cc);
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}
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/* --- Now recurse into its children, if any
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