/* Compute look-ahead criteria for bison,
- Copyright (C) 1984, 1986, 1989 Free Software Foundation, Inc.
+ Copyright 1984, 1986, 1989, 2000, 2001 Free Software Foundation, Inc.
-This file is part of Bison, the GNU Compiler Compiler.
+ This file is part of Bison, the GNU Compiler Compiler.
-Bison is free software; you can redistribute it and/or modify
-it under the terms of the GNU General Public License as published by
-the Free Software Foundation; either version 2, or (at your option)
-any later version.
+ Bison is free software; you can redistribute it and/or modify
+ it under the terms of the GNU General Public License as published by
+ the Free Software Foundation; either version 2, or (at your option)
+ any later version.
-Bison is distributed in the hope that it will be useful,
-but WITHOUT ANY WARRANTY; without even the implied warranty of
-MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
-GNU General Public License for more details.
+ Bison is distributed in the hope that it will be useful,
+ but WITHOUT ANY WARRANTY; without even the implied warranty of
+ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ GNU General Public License for more details.
-You should have received a copy of the GNU General Public License
-along with Bison; see the file COPYING. If not, write to
-the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
-Boston, MA 02111-1307, USA. */
+ You should have received a copy of the GNU General Public License
+ along with Bison; see the file COPYING. If not, write to
+ the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
+ Boston, MA 02111-1307, USA. */
/* Compute how to make the finite state machine deterministic; find
which rules need lookahead in each state, and which lookahead
- tokens they accept. */
+ tokens they accept. */
#include "system.h"
#include "types.h"
-#include "state.h"
-#include "alloc.h"
+#include "LR0.h"
#include "gram.h"
#include "complain.h"
#include "lalr.h"
+#include "nullable.h"
+#include "derives.h"
+#include "getargs.h"
-extern short **derives;
-extern char *nullable;
-
+/* All the decorated states, indexed by the state number. */
+state_t **state_table = NULL;
int tokensetsize;
-short *lookaheads;
short *LAruleno;
unsigned *LA;
-short *accessing_symbol;
-char *consistent;
-core **state_table;
-shifts **shift_table;
-reductions **reduction_table;
+size_t nLA;
+
+static int ngotos;
short *goto_map;
short *from_state;
short *to_state;
-extern void berror PARAMS ((const char *));
+/* And for the famous F variable, which name is so descriptive that a
+ comment is hardly needed. <grin>. */
+static unsigned *F = NULL;
+#define F(Rule) (F + (Rule) * tokensetsize)
-static int infinity;
-static int maxrhs;
-static int ngotos;
-static unsigned *F;
static short **includes;
static shorts **lookback;
+
+
+/*---------------------------------------------------------------.
+| digraph & traverse. |
+| |
+| The following variables are used as common storage between the |
+| two. |
+`---------------------------------------------------------------*/
+
static short **R;
static short *INDEX;
static short *VERTICES;
static int top;
-
+static int infinity;
static void
traverse (int i)
{
- unsigned *fp1;
- unsigned *fp2;
- unsigned *fp3;
int j;
- short *rp;
-
+ size_t k;
int height;
- unsigned *base;
+ size_t size = F (i + 1) - F(i);
VERTICES[++top] = i;
INDEX[i] = height = top;
- base = F + i * tokensetsize;
- fp3 = base + tokensetsize;
+ if (R[i])
+ for (j = 0; R[i][j] >= 0; ++j)
+ {
+ if (INDEX[R[i][j]] == 0)
+ traverse (R[i][j]);
- rp = R[i];
- if (rp)
- {
- while ((j = *rp++) >= 0)
- {
- if (INDEX[j] == 0)
- traverse (j);
-
- if (INDEX[i] > INDEX[j])
- INDEX[i] = INDEX[j];
+ if (INDEX[i] > INDEX[R[i][j]])
+ INDEX[i] = INDEX[R[i][j]];
- fp1 = base;
- fp2 = F + j * tokensetsize;
-
- while (fp1 < fp3)
- *fp1++ |= *fp2++;
- }
- }
+ for (k = 0; k < size; ++k)
+ F (i)[k] |= F (R[i][j])[k];
+ }
if (INDEX[i] == height)
- {
- for (;;)
- {
- j = VERTICES[top--];
- INDEX[j] = infinity;
+ for (;;)
+ {
+ j = VERTICES[top--];
+ INDEX[j] = infinity;
- if (i == j)
- break;
+ if (i == j)
+ break;
- fp1 = base;
- fp2 = F + j * tokensetsize;
-
- while (fp1 < fp3)
- *fp2++ = *fp1++;
- }
- }
+ for (k = 0; k < size; ++k)
+ F (j)[k] = F (i)[k];
+ }
}
int i;
infinity = ngotos + 2;
- INDEX = NEW2 (ngotos + 1, short);
- VERTICES = NEW2 (ngotos + 1, short);
+ INDEX = XCALLOC (short, ngotos + 1);
+ VERTICES = XCALLOC (short, ngotos + 1);
top = 0;
R = relation;
INDEX[i] = 0;
for (i = 0; i < ngotos; i++)
- {
- if (INDEX[i] == 0 && R[i])
- traverse (i);
- }
-
- FREE (INDEX);
- FREE (VERTICES);
-}
-
-static void
-set_state_table (void)
-{
- core *sp;
-
- state_table = NEW2 (nstates, core *);
-
- for (sp = first_state; sp; sp = sp->next)
- state_table[sp->number] = sp;
-}
-
-
-static void
-set_accessing_symbol (void)
-{
- core *sp;
-
- accessing_symbol = NEW2 (nstates, short);
-
- for (sp = first_state; sp; sp = sp->next)
- accessing_symbol[sp->number] = sp->accessing_symbol;
-}
-
-
-static void
-set_shift_table (void)
-{
- shifts *sp;
+ if (INDEX[i] == 0 && R[i])
+ traverse (i);
- shift_table = NEW2 (nstates, shifts *);
-
- for (sp = first_shift; sp; sp = sp->next)
- shift_table[sp->number] = sp;
-}
-
-
-static void
-set_reduction_table (void)
-{
- reductions *rp;
-
- reduction_table = NEW2 (nstates, reductions *);
-
- for (rp = first_reduction; rp; rp = rp->next)
- reduction_table[rp->number] = rp;
-}
-
-
-static void
-set_maxrhs (void)
-{
- short *itemp;
- int length;
- int max;
-
- length = 0;
- max = 0;
- for (itemp = ritem; *itemp; itemp++)
- {
- if (*itemp > 0)
- {
- length++;
- }
- else
- {
- if (length > max)
- max = length;
- length = 0;
- }
- }
-
- maxrhs = max;
+ XFREE (INDEX);
+ XFREE (VERTICES);
}
{
int i;
int j;
- int count;
- reductions *rp;
- shifts *sp;
short *np;
+ reductions *rp;
- consistent = NEW2 (nstates, char);
- lookaheads = NEW2 (nstates + 1, short);
-
- count = 0;
- for (i = 0; i < nstates; i++)
- {
- int k;
-
- lookaheads[i] = count;
-
- rp = reduction_table[i];
- sp = shift_table[i];
- if (rp && (rp->nreds > 1
- || (sp && !ISVAR (accessing_symbol[sp->shifts[0]]))))
- count += rp->nreds;
- else
- consistent[i] = 1;
-
- if (sp)
- for (k = 0; k < sp->nshifts; k++)
- {
- if (accessing_symbol[sp->shifts[k]] == error_token_number)
- {
- consistent[i] = 0;
- break;
- }
- }
- }
-
- lookaheads[nstates] = count;
+ /* Avoid having to special case 0. */
+ if (!nLA)
+ nLA = 1;
- if (count == 0)
- {
- LA = NEW2 (1 * tokensetsize, unsigned);
- LAruleno = NEW2 (1, short);
- lookback = NEW2 (1, shorts *);
- }
- else
- {
- LA = NEW2 (count * tokensetsize, unsigned);
- LAruleno = NEW2 (count, short);
- lookback = NEW2 (count, shorts *);
- }
+ LA = XCALLOC (unsigned, nLA * tokensetsize);
+ LAruleno = XCALLOC (short, nLA);
+ lookback = XCALLOC (shorts *, nLA);
np = LAruleno;
for (i = 0; i < nstates; i++)
- {
- if (!consistent[i])
- {
- if ((rp = reduction_table[i]))
- for (j = 0; j < rp->nreds; j++)
- *np++ = rp->rules[j];
- }
- }
+ if (!state_table[i]->consistent)
+ if ((rp = state_table[i]->reductions))
+ for (j = 0; j < rp->nreds; j++)
+ *np++ = rp->rules[j];
}
static void
set_goto_map (void)
{
- shifts *sp;
- int i;
- int symbol;
- int k;
+ int state, i;
short *temp_map;
- int state2;
- int state1;
- goto_map = NEW2 (nvars + 1, short) - ntokens;
- temp_map = NEW2 (nvars + 1, short) - ntokens;
+ goto_map = XCALLOC (short, nvars + 1) - ntokens;
+ temp_map = XCALLOC (short, nvars + 1) - ntokens;
ngotos = 0;
- for (sp = first_shift; sp; sp = sp->next)
+ for (state = 0; state < nstates; ++state)
{
- for (i = sp->nshifts - 1; i >= 0; i--)
+ shifts *sp = state_table[state]->shifts;
+ for (i = sp->nshifts - 1; i >= 0 && SHIFT_IS_GOTO (sp, i); --i)
{
- symbol = accessing_symbol[sp->shifts[i]];
-
- if (ISTOKEN (symbol))
- break;
+ int symbol = state_table[sp->shifts[i]]->accessing_symbol;
if (ngotos == MAXSHORT)
fatal (_("too many gotos (max %d)"), MAXSHORT);
}
}
- k = 0;
- for (i = ntokens; i < nsyms; i++)
- {
- temp_map[i] = k;
- k += goto_map[i];
- }
+ {
+ int k = 0;
+ for (i = ntokens; i < nsyms; i++)
+ {
+ temp_map[i] = k;
+ k += goto_map[i];
+ }
- for (i = ntokens; i < nsyms; i++)
- goto_map[i] = temp_map[i];
+ for (i = ntokens; i < nsyms; i++)
+ goto_map[i] = temp_map[i];
- goto_map[nsyms] = ngotos;
- temp_map[nsyms] = ngotos;
+ goto_map[nsyms] = ngotos;
+ temp_map[nsyms] = ngotos;
+ }
- from_state = NEW2 (ngotos, short);
- to_state = NEW2 (ngotos, short);
+ from_state = XCALLOC (short, ngotos);
+ to_state = XCALLOC (short, ngotos);
- for (sp = first_shift; sp; sp = sp->next)
+ for (state = 0; state < nstates; ++state)
{
- state1 = sp->number;
- for (i = sp->nshifts - 1; i >= 0; i--)
+ shifts *sp = state_table[state]->shifts;
+ for (i = sp->nshifts - 1; i >= 0 && SHIFT_IS_GOTO (sp, i); --i)
{
- state2 = sp->shifts[i];
- symbol = accessing_symbol[state2];
+ int state2 = sp->shifts[i];
+ int symbol = state_table[state2]->accessing_symbol;
- if (ISTOKEN (symbol))
- break;
-
- k = temp_map[symbol]++;
- from_state[k] = state1;
+ int k = temp_map[symbol]++;
+ from_state[k] = state;
to_state[k] = state2;
}
}
- FREE (temp_map + ntokens);
+ XFREE (temp_map + ntokens);
}
-/* Map_goto maps a state/symbol pair into its numeric representation. */
+/*----------------------------------------------------------.
+| Map a state/symbol pair into its numeric representation. |
+`----------------------------------------------------------*/
static int
map_goto (int state, int symbol)
high = middle - 1;
}
- berror ("map_goto");
-/* NOTREACHED */
+ assert (0);
+ /* NOTREACHED */
return 0;
}
static void
initialize_F (void)
{
+ short **reads = XCALLOC (short *, ngotos);
+ short *edge = XCALLOC (short, ngotos + 1);
+ int nedges = 0;
+
int i;
- int j;
- int k;
- shifts *sp;
- short *edge;
- unsigned *rowp;
- short *rp;
- short **reads;
- int nedges;
- int stateno;
- int symbol;
- int nwords;
-
- nwords = ngotos * tokensetsize;
- F = NEW2 (nwords, unsigned);
-
- reads = NEW2 (ngotos, short *);
- edge = NEW2 (ngotos + 1, short);
- nedges = 0;
-
- rowp = F;
+
+ F = XCALLOC (unsigned, ngotos * tokensetsize);
+
for (i = 0; i < ngotos; i++)
{
- stateno = to_state[i];
- sp = shift_table[stateno];
+ int stateno = to_state[i];
+ shifts *sp = state_table[stateno]->shifts;
- if (sp)
+ int j;
+ for (j = 0; j < sp->nshifts && SHIFT_IS_SHIFT (sp, j); j++)
{
- k = sp->nshifts;
-
- for (j = 0; j < k; j++)
- {
- symbol = accessing_symbol[sp->shifts[j]];
- if (ISVAR (symbol))
- break;
- SETBIT (rowp, symbol);
- }
-
- for (; j < k; j++)
- {
- symbol = accessing_symbol[sp->shifts[j]];
- if (nullable[symbol])
- edge[nedges++] = map_goto (stateno, symbol);
- }
-
- if (nedges)
- {
- reads[i] = rp = NEW2 (nedges + 1, short);
-
- for (j = 0; j < nedges; j++)
- rp[j] = edge[j];
+ int symbol = state_table[sp->shifts[j]]->accessing_symbol;
+ SETBIT (F (i), symbol);
+ }
- rp[nedges] = -1;
- nedges = 0;
- }
+ for (; j < sp->nshifts; j++)
+ {
+ int symbol = state_table[sp->shifts[j]]->accessing_symbol;
+ if (nullable[symbol])
+ edge[nedges++] = map_goto (stateno, symbol);
}
- rowp += tokensetsize;
+ if (nedges)
+ {
+ reads[i] = XCALLOC (short, nedges + 1);
+ shortcpy (reads[i], edge, nedges);
+ reads[i][nedges] = -1;
+ nedges = 0;
+ }
}
digraph (reads);
for (i = 0; i < ngotos; i++)
- {
- if (reads[i])
- FREE (reads[i]);
- }
+ XFREE (reads[i]);
- FREE (reads);
- FREE (edge);
+ XFREE (reads);
+ XFREE (edge);
}
static void
-add_lookback_edge (int stateno, int ruleno, int gotono)
+add_lookback_edge (state_t *state, int ruleno, int gotono)
{
int i;
- int k;
- int found;
shorts *sp;
- i = lookaheads[stateno];
- k = lookaheads[stateno + 1];
- found = 0;
- while (!found && i < k)
- {
- if (LAruleno[i] == ruleno)
- found = 1;
- else
- i++;
- }
+ for (i = 0; i < state->nlookaheads; ++i)
+ if (LAruleno[state->lookaheadsp + i] == ruleno)
+ break;
- if (found == 0)
- berror ("add_lookback_edge");
+ assert (LAruleno[state->lookaheadsp + i] == ruleno);
- sp = NEW (shorts);
- sp->next = lookback[i];
+ sp = XCALLOC (shorts, 1);
+ sp->next = lookback[state->lookaheadsp + i];
sp->value = gotono;
- lookback[i] = sp;
+ lookback[state->lookaheadsp + i] = sp;
}
-static short **
-transpose (short **R_arg, int n)
+static void
+matrix_print (FILE *out, short **matrix, int n)
{
- short **new_R;
- short **temp_R;
- short *nedges;
- short *sp;
- int i;
- int k;
+ int i, j;
- nedges = NEW2 (n, short);
+ for (i = 0; i < n; ++i)
+ {
+ fprintf (out, "%3d: ", i);
+ if (matrix[i])
+ for (j = 0; matrix[i][j] != -1; ++j)
+ fprintf (out, "%3d ", matrix[i][j]);
+ fputc ('\n', out);
+ }
+ fputc ('\n', out);
+}
- for (i = 0; i < n; i++)
+/*-------------------------------------------------------------------.
+| Return the transpose of R_ARG, of size N. Destroy R_ARG, as it is |
+| replaced with the result. |
+| |
+| R_ARG[I] is NULL or a -1 terminated list of numbers. |
+| |
+| RESULT[NUM] is NULL or the -1 terminated list of the I such as NUM |
+| is in R_ARG[I]. |
+`-------------------------------------------------------------------*/
+
+static short **
+transpose (short **R_arg, int n)
+{
+ /* The result. */
+ short **new_R = XCALLOC (short *, n);
+ /* END_R[I] -- next entry of NEW_R[I]. */
+ short **end_R = XCALLOC (short *, n);
+ /* NEDGES[I] -- total size of NEW_R[I]. */
+ short *nedges = XCALLOC (short, n);
+ int i, j;
+
+ if (trace_flag)
{
- sp = R_arg[i];
- if (sp)
- {
- while (*sp >= 0)
- nedges[*sp++]++;
- }
+ fputs ("transpose: input\n", stderr);
+ matrix_print (stderr, R_arg, n);
}
- new_R = NEW2 (n, short *);
- temp_R = NEW2 (n, short *);
+ /* Count. */
+ for (i = 0; i < n; i++)
+ if (R_arg[i])
+ for (j = 0; R_arg[i][j] >= 0; ++j)
+ ++nedges[R_arg[i][j]];
+ /* Allocate. */
for (i = 0; i < n; i++)
- {
- k = nedges[i];
- if (k > 0)
+ if (nedges[i] > 0)
+ {
+ short *sp = XCALLOC (short, nedges[i] + 1);
+ sp[nedges[i]] = -1;
+ new_R[i] = sp;
+ end_R[i] = sp;
+ }
+
+ /* Store. */
+ for (i = 0; i < n; i++)
+ if (R_arg[i])
+ for (j = 0; R_arg[i][j] >= 0; ++j)
{
- sp = NEW2 (k + 1, short);
- new_R[i] = sp;
- temp_R[i] = sp;
- sp[k] = -1;
+ *end_R[R_arg[i][j]] = i;
+ ++end_R[R_arg[i][j]];
}
- }
- FREE (nedges);
+ free (nedges);
+ free (end_R);
+ /* Free the input: it is replaced with the result. */
for (i = 0; i < n; i++)
+ XFREE (R_arg[i]);
+ free (R_arg);
+
+ if (trace_flag)
{
- sp = R_arg[i];
- if (sp)
- {
- while (*sp >= 0)
- *temp_R[*sp++]++ = i;
- }
+ fputs ("transpose: output\n", stderr);
+ matrix_print (stderr, new_R, n);
}
- FREE (temp_R);
-
return new_R;
}
static void
build_relations (void)
{
+ short *edge = XCALLOC (short, ngotos + 1);
+ short *states = XCALLOC (short, ritem_longest_rhs () + 1);
int i;
- int j;
- int k;
- short *rulep;
- short *rp;
- shifts *sp;
- int length;
- int nedges;
- int done;
- int state1;
- int stateno;
- int symbol1;
- int symbol2;
- short *shortp;
- short *edge;
- short *states;
- short **new_includes;
-
- includes = NEW2 (ngotos, short *);
- edge = NEW2 (ngotos + 1, short);
- states = NEW2 (maxrhs + 1, short);
+
+ includes = XCALLOC (short *, ngotos);
for (i = 0; i < ngotos; i++)
{
- nedges = 0;
- state1 = from_state[i];
- symbol1 = accessing_symbol[to_state[i]];
+ int nedges = 0;
+ int symbol1 = state_table[to_state[i]]->accessing_symbol;
+ short *rulep;
for (rulep = derives[symbol1]; *rulep > 0; rulep++)
{
- length = 1;
- states[0] = state1;
- stateno = state1;
+ int done;
+ int length = 1;
+ short *rp;
+ state_t *state = state_table[from_state[i]];
+ states[0] = state->number;
- for (rp = ritem + rrhs[*rulep]; *rp > 0; rp++)
+ for (rp = ritem + rule_table[*rulep].rhs; *rp > 0; rp++)
{
- symbol2 = *rp;
- sp = shift_table[stateno];
- k = sp->nshifts;
-
- for (j = 0; j < k; j++)
+ shifts *sp = state->shifts;
+ int j;
+ for (j = 0; j < sp->nshifts; j++)
{
- stateno = sp->shifts[j];
- if (accessing_symbol[stateno] == symbol2)
+ state = state_table[sp->shifts[j]];
+ if (state->accessing_symbol == *rp)
break;
}
- states[length++] = stateno;
+ states[length++] = state->number;
}
- if (!consistent[stateno])
- add_lookback_edge (stateno, *rulep, i);
+ if (!state->consistent)
+ add_lookback_edge (state, *rulep, i);
length--;
done = 0;
/* JF added rp>=ritem && I hope to god its right! */
if (rp >= ritem && ISVAR (*rp))
{
- stateno = states[--length];
- edge[nedges++] = map_goto (stateno, *rp);
+ edge[nedges++] = map_goto (states[--length], *rp);
if (nullable[*rp])
done = 0;
}
if (nedges)
{
- includes[i] = shortp = NEW2 (nedges + 1, short);
+ int j;
+ includes[i] = XCALLOC (short, nedges + 1);
for (j = 0; j < nedges; j++)
- shortp[j] = edge[j];
- shortp[nedges] = -1;
+ includes[i][j] = edge[j];
+ includes[i][nedges] = -1;
}
}
- new_includes = transpose (includes, ngotos);
-
- for (i = 0; i < ngotos; i++)
- if (includes[i])
- FREE (includes[i]);
-
- FREE (includes);
-
- includes = new_includes;
+ XFREE (edge);
+ XFREE (states);
- FREE (edge);
- FREE (states);
+ includes = transpose (includes, ngotos);
}
digraph (includes);
for (i = 0; i < ngotos; i++)
- {
- if (includes[i])
- FREE (includes[i]);
- }
+ XFREE (includes[i]);
- FREE (includes);
+ XFREE (includes);
}
static void
compute_lookaheads (void)
{
- int i;
- int n;
- unsigned *fp1;
- unsigned *fp2;
- unsigned *fp3;
+ size_t i;
shorts *sp;
- unsigned *rowp;
- shorts *sptmp; /* JF */
- rowp = LA;
- n = lookaheads[nstates];
- for (i = 0; i < n; i++)
- {
- fp3 = rowp + tokensetsize;
- for (sp = lookback[i]; sp; sp = sp->next)
- {
- fp1 = rowp;
- fp2 = F + tokensetsize * sp->value;
- while (fp1 < fp3)
- *fp1++ |= *fp2++;
- }
+ for (i = 0; i < nLA; i++)
+ for (sp = lookback[i]; sp; sp = sp->next)
+ {
+ int size = LA (i + 1) - LA (i);
+ int j;
+ for (j = 0; j < size; ++j)
+ LA (i)[j] |= F (sp->value)[j];
+ }
+
+ /* Free LOOKBACK. */
+ for (i = 0; i < nLA; i++)
+ LIST_FREE (shorts, lookback[i]);
+
+ XFREE (lookback);
+ XFREE (F);
+}
- rowp = fp3;
- }
- for (i = 0; i < n; i++)
+/*--------------------------------------.
+| Initializing the lookaheads members. |
+`--------------------------------------*/
+
+static void
+initialize_lookaheads (void)
+{
+ int i;
+ nLA = 0;
+ for (i = 0; i < nstates; i++)
{
- /* JF removed ref to freed storage */
- for (sp = lookback[i]; sp; sp = sptmp)
- {
- sptmp = sp->next;
- FREE (sp);
- }
- }
+ int k;
+ int nlookaheads = 0;
+ reductions *rp = state_table[i]->reductions;
+ shifts *sp = state_table[i]->shifts;
- FREE (lookback);
- FREE (F);
-}
+ if (rp
+ && (rp->nreds > 1 || (sp->nshifts && SHIFT_IS_SHIFT (sp, 0))))
+ nlookaheads += rp->nreds;
+ else
+ state_table[i]->consistent = 1;
+ for (k = 0; k < sp->nshifts; k++)
+ if (SHIFT_IS_ERROR (sp, k))
+ {
+ state_table[i]->consistent = 0;
+ break;
+ }
+
+ state_table[i]->nlookaheads = nlookaheads;
+ state_table[i]->lookaheadsp = nLA;
+ nLA += nlookaheads;
+ }
+}
void
lalr (void)
{
tokensetsize = WORDSIZE (ntokens);
- set_state_table ();
- set_accessing_symbol ();
- set_shift_table ();
- set_reduction_table ();
- set_maxrhs ();
+ initialize_lookaheads ();
initialize_LA ();
set_goto_map ();
initialize_F ();
projects / bison.git / blobdiff