From 0b0754d765b0c435be62198368e35e3af2b9bc62 Mon Sep 17 00:00:00 2001 From: Vladimir Prus Date: Tue, 28 Nov 2006 17:23:10 +0000 Subject: [PATCH] 2006-11-28 Vladimir Prus Fetch varobj values from memory in a single place, and only fetch the values that are really needed. * varobj.c (struct varobj): Clarify comment. (my_value_equal): Remove. (install_new_value): New function. (type_of_child): Remove. (varobj_create): Use install_new_value. (varobj_set_value): Use value_contents_equal, not my_value_equal. (varobj_update): Use install_new_value. (create_child): Likewise. Inline type_of_child here. (value_of_child): Don't fetch the value. (c_value_of_root): Likewise. (c_value_of_variable): Likewise. (type_changeable): Improve comments. --- gdb/ChangeLog | 18 +++ gdb/testsuite/ChangeLog | 7 + gdb/testsuite/gdb.mi/mi-var-cmd.exp | 37 +++++ gdb/testsuite/gdb.mi/var-cmd.c | 4 + gdb/varobj.c | 293 +++++++++++++++++++++--------------- 5 files changed, 235 insertions(+), 124 deletions(-) diff --git a/gdb/ChangeLog b/gdb/ChangeLog index 3c8f9d9de5..c1c602694d 100644 --- a/gdb/ChangeLog +++ b/gdb/ChangeLog @@ -1,3 +1,21 @@ +2006-11-28 Vladimir Prus + + Fetch varobj values from memory in a single place, + and only fetch the values that are really needed. + * varobj.c (struct varobj): Clarify comment. + (my_value_equal): Remove. + (install_new_value): New function. + (type_of_child): Remove. + (varobj_create): Use install_new_value. + (varobj_set_value): Use value_contents_equal, not + my_value_equal. + (varobj_update): Use install_new_value. + (create_child): Likewise. Inline type_of_child here. + (value_of_child): Don't fetch the value. + (c_value_of_root): Likewise. + (c_value_of_variable): Likewise. + (type_changeable): Improve comments. + 2006-11-28 Daniel Jacobowitz * remote.c (struct remote_arch_state): Doc fix. diff --git a/gdb/testsuite/ChangeLog b/gdb/testsuite/ChangeLog index 40685ea917..c6550e4c38 100644 --- a/gdb/testsuite/ChangeLog +++ b/gdb/testsuite/ChangeLog @@ -1,3 +1,10 @@ +2006-11-28 Vladimir Prus + + * gdb.mi/mi-var-cmd.exp: Check -var-update after + assignement of arrays and function pointers. + * gdb.mi/var-cmd.c: Add declaration necessary for above + tests. + 2006-11-27 Nathan Sidwell * gdb.base/break.c (main): Call malloc. diff --git a/gdb/testsuite/gdb.mi/mi-var-cmd.exp b/gdb/testsuite/gdb.mi/mi-var-cmd.exp index a6023e9f2f..7efb438449 100644 --- a/gdb/testsuite/gdb.mi/mi-var-cmd.exp +++ b/gdb/testsuite/gdb.mi/mi-var-cmd.exp @@ -382,6 +382,43 @@ mi_gdb_test "-var-assign lsimple.integer 333" \ "\\^done,value=\"333\"" \ "assign to lsimple.integer" +mi_gdb_test "-var-update *" \ + "\\^done,changelist=.*" \ + "var update" + +# Check that assignment of function and array values +# promotes the assigned value to function pointer/data +# pointer before comparing with the existing value, +# and does not incorrectly make the value as changed. +mi_gdb_test "-var-assign func do_block_tests" \ + "\\^done,value=\"$hex \"" \ + "assign same value to func" + +mi_gdb_test "-var-update *" \ + "\\^done,changelist=\\\[\\\]" \ + "assign same value to func (update)" + +mi_gdb_test "-var-create array_ptr * array_ptr" \ + "\\^done,name=\"array_ptr\",numchild=\"1\",type=\"int \\*\"" \ + "create global variable array_ptr" + +mi_gdb_test "-var-assign array_ptr array2" \ + "\\^done,value=\"$hex\"" \ + "assign array to pointer" + +mi_gdb_test "-var-update *" \ + "\\^done,changelist=\\\[\{name=\"array_ptr\",in_scope=\"true\",type_changed=\"false\"\}\\\]" \ + "assign array to pointer (update)" + +mi_gdb_test "-var-assign array_ptr array2" \ + "\\^done,value=\"$hex\"" \ + "assign same array to pointer" + +mi_gdb_test "-var-update *" \ + "\\^done,changelist=\\\[\\\]" \ + "assign same array to pointer (update)" + + ###### # End of assign tests ##### diff --git a/gdb/testsuite/gdb.mi/var-cmd.c b/gdb/testsuite/gdb.mi/var-cmd.c index 761e804cb0..d0eb6f81d9 100644 --- a/gdb/testsuite/gdb.mi/var-cmd.c +++ b/gdb/testsuite/gdb.mi/var-cmd.c @@ -106,6 +106,10 @@ void incr_a (char a) b = a; } +int array[] = {1,2,3}; +int array2[] = {4,5,6}; +int *array_ptr = array; + void do_locals_tests () { diff --git a/gdb/varobj.c b/gdb/varobj.c index c664bfd097..42ed597f29 100644 --- a/gdb/varobj.c +++ b/gdb/varobj.c @@ -101,7 +101,9 @@ struct varobj /* The type of this variable. This may NEVER be NULL. */ struct type *type; - /* The value of this expression or subexpression. This may be NULL. */ + /* The value of this expression or subexpression. This may be NULL. + Invariant: if type_changeable (this) is non-zero, the value is either + NULL, or not lazy. */ struct value *value; /* Did an error occur evaluating the expression or getting its value? */ @@ -202,8 +204,6 @@ static struct type *get_target_type (struct type *); static enum varobj_display_formats variable_default_display (struct varobj *); -static int my_value_equal (struct value *, struct value *, int *); - static void vpush (struct vstack **pstack, struct varobj *var); static struct varobj *vpop (struct vstack **pstack); @@ -212,6 +212,9 @@ static void cppush (struct cpstack **pstack, char *name); static char *cppop (struct cpstack **pstack); +static int install_new_value (struct varobj *var, struct value *value, + int initial); + /* Language-specific routines. */ static enum varobj_languages variable_language (struct varobj *var); @@ -226,8 +229,6 @@ static struct value *value_of_root (struct varobj **var_handle, int *); static struct value *value_of_child (struct varobj *parent, int index); -static struct type *type_of_child (struct varobj *var); - static int variable_editable (struct varobj *var); static char *my_value_of_variable (struct varobj *var); @@ -445,6 +446,7 @@ varobj_create (char *objname, { char *p; enum varobj_languages lang; + struct value *value; /* Parse and evaluate the expression, filling in as much of the variable's data as possible */ @@ -505,17 +507,16 @@ varobj_create (char *objname, /* We definitively need to catch errors here. If evaluate_expression succeeds we got the value we wanted. But if it fails, we still go on with a call to evaluate_type() */ - if (gdb_evaluate_expression (var->root->exp, &var->value)) - { - /* no error */ - release_value (var->value); - if (value_lazy (var->value)) - gdb_value_fetch_lazy (var->value); - } - else - var->value = evaluate_type (var->root->exp); + if (!gdb_evaluate_expression (var->root->exp, &value)) + /* Error getting the value. Try to at least get the + right type. */ + value = evaluate_type (var->root->exp); + + release_value (value); + + var->type = value_type (value); - var->type = value_type (var->value); + install_new_value (var, value, 1 /* Initial assignment */); /* Set language info */ lang = variable_language (var); @@ -825,8 +826,28 @@ varobj_set_value (struct varobj *var, char *expression) return 0; } - if (!my_value_equal (var->value, value, &error)) + /* All types that are editable must also be changeable. */ + gdb_assert (type_changeable (var)); + + /* The value of a changeable variable object must not be lazy. */ + gdb_assert (!value_lazy (var->value)); + + /* Need to coerce the input. We want to check if the + value of the variable object will be different + after assignment, and the first thing value_assign + does is coerce the input. + For example, if we are assigning an array to a pointer variable we + should compare the pointer with the the array's address, not with the + array's content. */ + value = coerce_array (value); + + if (!value_contents_equal (var->value, value)) var->updated = 1; + + /* The new value may be lazy. gdb_value_assign, or + rather value_contents, will take care of this. + If fetching of the new value will fail, gdb_value_assign + with catch the exception. */ if (!gdb_value_assign (var->value, value, &val)) return 0; value_free (var->value); @@ -870,6 +891,101 @@ varobj_list (struct varobj ***varlist) return rootcount; } +/* Assign a new value to a variable object. If INITIAL is non-zero, + this is the first assignement after the variable object was just + created, or changed type. In that case, just assign the value + and return 0. + Otherwise, assign the value and if type_changeable returns non-zero, + find if the new value is different from the current value. + Return 1 if so, and 0 if the values are equal. */ +static int +install_new_value (struct varobj *var, struct value *value, int initial) +{ + int changeable; + int need_to_fetch; + int changed = 0; + + var->error = 0; + /* We need to know the varobj's type to decide if the value should + be fetched or not. C++ fake children (public/protected/private) don't have + a type. */ + gdb_assert (var->type || CPLUS_FAKE_CHILD (var)); + changeable = type_changeable (var); + need_to_fetch = changeable; + + if (var->type && TYPE_CODE (var->type) == TYPE_CODE_UNION) + /* For unions, we need to fetch the value implicitly because + of implementation of union member fetch. When gdb + creates a value for a field and the value of the enclosing + structure is not lazy, it immediately copies the necessary + bytes from the enclosing values. If the enclosing value is + lazy, the call to value_fetch_lazy on the field will read + the data from memory. For unions, that means we'll read the + same memory more than once, which is not desirable. So + fetch now. */ + need_to_fetch = 1; + + /* The new value might be lazy. If the type is changeable, + that is we'll be comparing values of this type, fetch the + value now. Otherwise, on the next update the old value + will be lazy, which means we've lost that old value. */ + if (need_to_fetch && value && value_lazy (value)) + { + if (!gdb_value_fetch_lazy (value)) + { + var->error = 1; + /* Set the value to NULL, so that for the next -var-update, + we don't try to compare the new value with this value, + that we couldn't even read. */ + value = NULL; + } + else + var->error = 0; + } + + /* If the type is changeable, compare the old and the new values. + If this is the initial assignment, we don't have any old value + to compare with. */ + if (!initial && changeable) + { + /* If the value of the varobj was changed by -var-set-value, then the + value in the varobj and in the target is the same. However, that value + is different from the value that the varobj had after the previous + -var-update. So need to the varobj as changed. */ + if (var->updated) + changed = 1; + else + { + /* Try to compare the values. That requires that both + values are non-lazy. */ + + /* Quick comparison of NULL values. */ + if (var->value == NULL && value == NULL) + /* Equal. */ + ; + else if (var->value == NULL || value == NULL) + changed = 1; + else + { + gdb_assert (!value_lazy (var->value)); + gdb_assert (!value_lazy (value)); + + if (!value_contents_equal (var->value, value)) + changed = 1; + } + } + } + + /* We must always keep the new value, since children depend on it. */ + if (var->value != NULL) + value_free (var->value); + var->value = value; + var->updated = 0; + + return changed; +} + + /* Update the values for a variable and its children. This is a two-pronged attack. First, re-parse the value for the root's expression to see if it's changed. Then go all the way @@ -939,24 +1055,16 @@ varobj_update (struct varobj **varp, struct varobj ***changelist) vpush (&result, *varp); changed++; } - /* If values are not equal, note that it's changed. - There a couple of exceptions here, though. - We don't want some types to be reported as "changed". */ - else if (type_changeable (*varp) && - ((*varp)->updated || !my_value_equal ((*varp)->value, new, &error))) + + if (install_new_value ((*varp), new, type_changed)) { - vpush (&result, *varp); - (*varp)->updated = 0; + /* If type_changed is 1, install_new_value will never return + non-zero, so we'll never report the same variable twice. */ + gdb_assert (!type_changed); + vpush (&result, (*varp)); changed++; - /* Its value is going to be updated to NEW. */ - (*varp)->error = error; } - /* We must always keep around the new value for this root - variable expression, or we lose the updated children! */ - value_free ((*varp)->value); - (*varp)->value = new; - /* Initialize a stack */ vpush (&stack, NULL); @@ -982,21 +1090,13 @@ varobj_update (struct varobj **varp, struct varobj ***changelist) /* Update this variable */ new = value_of_child (v->parent, v->index); - if (type_changeable (v) && - (v->updated || !my_value_equal (v->value, new, &error))) - { + if (install_new_value (v, new, 0 /* type not changed */)) + { /* Note that it's changed */ vpush (&result, v); v->updated = 0; changed++; } - /* Its value is going to be updated to NEW. */ - v->error = error; - - /* We must always keep new values, since children depend on it. */ - if (v->value != NULL) - value_free (v->value); - v->value = new; /* Get next child */ v = vpop (&stack); @@ -1257,15 +1357,14 @@ create_child (struct varobj *parent, int index, char *name) { struct varobj *child; char *childs_name; + struct value *value; child = new_variable (); /* name is allocated by name_of_child */ child->name = name; child->index = index; - child->value = value_of_child (parent, index); - if ((!CPLUS_FAKE_CHILD (child) && child->value == NULL) || parent->error) - child->error = 1; + value = value_of_child (parent, index); child->parent = parent; child->root = parent->root; childs_name = xstrprintf ("%s.%s", parent->obj_name, name); @@ -1275,8 +1374,20 @@ create_child (struct varobj *parent, int index, char *name) /* Save a pointer to this child in the parent */ save_child_in_parent (parent, child); - /* Note the type of this child */ - child->type = type_of_child (child); + /* Compute the type of the child. Must do this before + calling install_new_value. */ + if (value != NULL) + /* If the child had no evaluation errors, var->value + will be non-NULL and contain a valid type. */ + child->type = value_type (value); + else + /* Otherwise, we must compute the type. */ + child->type = (*child->root->lang->type_of_child) (child->parent, + child->index); + install_new_value (child, value, 1); + + if ((!CPLUS_FAKE_CHILD (child) && child->value == NULL) || parent->error) + child->error = 1; return child; } @@ -1451,42 +1562,6 @@ variable_default_display (struct varobj *var) return FORMAT_NATURAL; } -/* This function is similar to GDB's value_contents_equal, except that - this one is "safe"; it never longjmps. It determines if the VAL1's - value is the same as VAL2. If for some reason the value of VAR2 - can't be established, *ERROR2 is set to non-zero. */ - -static int -my_value_equal (struct value *val1, struct value *volatile val2, int *error2) -{ - volatile struct gdb_exception except; - - /* As a special case, if both are null, we say they're equal. */ - if (val1 == NULL && val2 == NULL) - return 1; - else if (val1 == NULL || val2 == NULL) - return 0; - - /* The contents of VAL1 are supposed to be known. */ - gdb_assert (!value_lazy (val1)); - - /* Make sure we also know the contents of VAL2. */ - val2 = coerce_array (val2); - TRY_CATCH (except, RETURN_MASK_ERROR) - { - if (value_lazy (val2)) - value_fetch_lazy (val2); - } - if (except.reason < 0) - { - *error2 = 1; - return 0; - } - gdb_assert (!value_lazy (val2)); - - return value_contents_equal (val1, val2); -} - /* FIXME: The following should be generic for any pointer */ static void vpush (struct vstack **pstack, struct varobj *var) @@ -1678,33 +1753,9 @@ value_of_child (struct varobj *parent, int index) value = (*parent->root->lang->value_of_child) (parent, index); - /* If we're being lazy, fetch the real value of the variable. */ - if (value != NULL && value_lazy (value)) - { - /* If we fail to fetch the value of the child, return - NULL so that callers notice that we're leaving an - error message. */ - if (!gdb_value_fetch_lazy (value)) - value = NULL; - } - return value; } -/* What is the type of VAR? */ -static struct type * -type_of_child (struct varobj *var) -{ - - /* If the child had no evaluation errors, var->value - will be non-NULL and contain a valid type. */ - if (var->value != NULL) - return value_type (var->value); - - /* Otherwise, we must compute the type. */ - return (*var->root->lang->type_of_child) (var->parent, var->index); -} - /* Is this variable editable? Use the variable's type to make this determination. */ static int @@ -1720,9 +1771,15 @@ my_value_of_variable (struct varobj *var) return (*var->root->lang->value_of_variable) (var); } -/* Is VAR something that can change? Depending on language, - some variable's values never change. For example, - struct and unions never change values. */ +/* Return non-zero if changes in value of VAR + must be detected and reported by -var-update. + Return zero is -var-update should never report + changes of such values. This makes sense for structures + (since the changes in children values will be reported separately), + or for artifical objects (like 'public' pseudo-field in C++). + + Return value of 0 means that gdb need not call value_fetch_lazy + for the value of this variable object. */ static int type_changeable (struct varobj *var) { @@ -1898,24 +1955,12 @@ c_value_of_root (struct varobj **var_handle) go on */ if (gdb_evaluate_expression (var->root->exp, &new_val)) { - if (value_lazy (new_val)) - { - /* We need to catch errors because if - value_fetch_lazy fails we still want to continue - (after making val->error = 1) */ - /* FIXME: Shouldn't be using value_contents()? The - comment on value_fetch_lazy() says it is only called - from the macro... */ - if (!gdb_value_fetch_lazy (new_val)) - var->error = 1; - else - var->error = 0; - } + var->error = 0; + release_value (new_val); } else var->error = 1; - release_value (new_val); return new_val; } @@ -2094,8 +2139,8 @@ c_value_of_variable (struct varobj *var) struct cleanup *old_chain = make_cleanup_ui_file_delete (stb); char *thevalue; - if (value_lazy (var->value)) - gdb_value_fetch_lazy (var->value); + gdb_assert (type_changeable (var)); + gdb_assert (!value_lazy (var->value)); common_val_print (var->value, stb, format_code[(int) var->format], 1, 0, 0); thevalue = ui_file_xstrdup (stb, &dummy); -- 2.11.0