[PATCH 5/9] kconfig: print more info when we see a recursive dependency

From: Sam Ravnborg
Date: Sat Jul 31 2010 - 17:35:47 EST


From: Roman Zippel <zippel@xxxxxxxxxxxxxx>

Consider following kconfig file:

config TEST1
bool "test 1"
depends on TEST2

config TEST2
bool "test 2"
depends on TEST1

Previously kconfig would report:

foo:6:error: found recursive dependency: TEST2 -> TEST1 -> TEST2

With the following patch kconfig reports:
foo:5:error: recursive dependency detected!
foo:5: symbol TEST2 depends on TEST1
foo:1: symbol TEST1 depends on TEST2

Note that we now report where the offending symbols are defined.
This can be a great help for complex situations involving
several files.

Patch is originally from Roman Zippel with a few adjustments by Sam.

Signed-off-by: Sam Ravnborg <sam@xxxxxxxxxxxx>
Cc: Roman Zippel <zippel@xxxxxxxxxxxxxx>
---
scripts/kconfig/symbol.c | 142 +++++++++++++++++++++++++++++++++++++++++-----
1 files changed, 127 insertions(+), 15 deletions(-)

diff --git a/scripts/kconfig/symbol.c b/scripts/kconfig/symbol.c
index 9f180ab..bc1e158 100644
--- a/scripts/kconfig/symbol.c
+++ b/scripts/kconfig/symbol.c
@@ -783,6 +783,110 @@ struct symbol **sym_re_search(const char *pattern)
return sym_arr;
}

+/*
+ * When we check for recursive dependencies we use a stack to save
+ * current state so we can print out relevant info to user.
+ * The entries are located on the call stack so no need to free memory.
+ * Note inser() remove() must always match to properly clear the stack.
+ */
+static struct dep_stack {
+ struct dep_stack *prev, *next;
+ struct symbol *sym;
+ struct property *prop;
+ struct expr *expr;
+} *check_top;
+
+static void dep_stack_insert(struct dep_stack *stack, struct symbol *sym)
+{
+ memset(stack, 0, sizeof(*stack));
+ if (check_top)
+ check_top->next = stack;
+ stack->prev = check_top;
+ stack->sym = sym;
+ check_top = stack;
+}
+
+static void dep_stack_remove(void)
+{
+ check_top = check_top->prev;
+ if (check_top)
+ check_top->next = NULL;
+}
+
+/*
+ * Called when we have detected a recursive dependency.
+ * check_top point to the top of the stact so we use
+ * the ->prev pointer to locate the bottom of the stack.
+ */
+static void sym_check_print_recursive(struct symbol *last_sym)
+{
+ struct dep_stack *stack;
+ struct symbol *sym, *next_sym;
+ struct menu *menu = NULL;
+ struct property *prop;
+ struct dep_stack cv_stack;
+
+ if (sym_is_choice_value(last_sym)) {
+ dep_stack_insert(&cv_stack, last_sym);
+ last_sym = prop_get_symbol(sym_get_choice_prop(last_sym));
+ }
+
+ for (stack = check_top; stack != NULL; stack = stack->prev)
+ if (stack->sym == last_sym)
+ break;
+ if (!stack) {
+ fprintf(stderr, "unexpected recursive dependency error\n");
+ return;
+ }
+
+ for (; stack; stack = stack->next) {
+ sym = stack->sym;
+ next_sym = stack->next ? stack->next->sym : last_sym;
+ prop = stack->prop;
+
+ /* for choice values find the menu entry (used below) */
+ if (sym_is_choice(sym) || sym_is_choice_value(sym)) {
+ for (prop = sym->prop; prop; prop = prop->next) {
+ menu = prop->menu;
+ if (prop->menu)
+ break;
+ }
+ }
+ if (stack->sym == last_sym)
+ fprintf(stderr, "%s:%d:error: recursive dependency detected!\n",
+ prop->file->name, prop->lineno);
+ if (stack->expr) {
+ fprintf(stderr, "%s:%d:\tsymbol %s %s value contains %s\n",
+ prop->file->name, prop->lineno,
+ sym->name ? sym->name : "<choice>",
+ prop_get_type_name(prop->type),
+ next_sym->name ? next_sym->name : "<choice>");
+ } else if (stack->prop) {
+ fprintf(stderr, "%s:%d:\tsymbol %s depends on %s\n",
+ prop->file->name, prop->lineno,
+ sym->name ? sym->name : "<choice>",
+ next_sym->name ? next_sym->name : "<choice>");
+ } else if (sym_is_choice(sym)) {
+ fprintf(stderr, "%s:%d:\tchoice %s contains symbol %s\n",
+ menu->file->name, menu->lineno,
+ sym->name ? sym->name : "<choice>",
+ next_sym->name ? next_sym->name : "<choice>");
+ } else if (sym_is_choice_value(sym)) {
+ fprintf(stderr, "%s:%d:\tsymbol %s is part of choice %s\n",
+ menu->file->name, menu->lineno,
+ sym->name ? sym->name : "<choice>",
+ next_sym->name ? next_sym->name : "<choice>");
+ } else {
+ fprintf(stderr, "%s:%d:\tsymbol %s is selected by %s\n",
+ prop->file->name, prop->lineno,
+ sym->name ? sym->name : "<choice>",
+ next_sym->name ? next_sym->name : "<choice>");
+ }
+ }
+
+ if (check_top == &cv_stack)
+ dep_stack_remove();
+}

static struct symbol *sym_check_expr_deps(struct expr *e)
{
@@ -819,24 +923,33 @@ static struct symbol *sym_check_sym_deps(struct symbol *sym)
{
struct symbol *sym2;
struct property *prop;
+ struct dep_stack stack;
+
+ dep_stack_insert(&stack, sym);

sym2 = sym_check_expr_deps(sym->rev_dep.expr);
if (sym2)
- return sym2;
+ goto out;

for (prop = sym->prop; prop; prop = prop->next) {
if (prop->type == P_CHOICE || prop->type == P_SELECT)
continue;
+ stack.prop = prop;
sym2 = sym_check_expr_deps(prop->visible.expr);
if (sym2)
break;
if (prop->type != P_DEFAULT || sym_is_choice(sym))
continue;
+ stack.expr = prop->expr;
sym2 = sym_check_expr_deps(prop->expr);
if (sym2)
break;
+ stack.expr = NULL;
}

+out:
+ dep_stack_remove();
+
return sym2;
}

@@ -845,6 +958,9 @@ static struct symbol *sym_check_choice_deps(struct symbol *choice)
struct symbol *sym, *sym2;
struct property *prop;
struct expr *e;
+ struct dep_stack stack;
+
+ dep_stack_insert(&stack, choice);

prop = sym_get_choice_prop(choice);
expr_list_for_each_sym(prop->expr, e, sym)
@@ -858,10 +974,8 @@ static struct symbol *sym_check_choice_deps(struct symbol *choice)

expr_list_for_each_sym(prop->expr, e, sym) {
sym2 = sym_check_sym_deps(sym);
- if (sym2) {
- fprintf(stderr, " -> %s", sym->name);
+ if (sym2)
break;
- }
}
out:
expr_list_for_each_sym(prop->expr, e, sym)
@@ -871,6 +985,8 @@ out:
prop_get_symbol(sym_get_choice_prop(sym2)) == choice)
sym2 = choice;

+ dep_stack_remove();
+
return sym2;
}

@@ -880,18 +996,20 @@ struct symbol *sym_check_deps(struct symbol *sym)
struct property *prop;

if (sym->flags & SYMBOL_CHECK) {
- fprintf(stderr, "%s:%d:error: found recursive dependency: %s",
- sym->prop->file->name, sym->prop->lineno,
- sym->name ? sym->name : "<choice>");
+ sym_check_print_recursive(sym);
return sym;
}
if (sym->flags & SYMBOL_CHECKED)
return NULL;

if (sym_is_choice_value(sym)) {
+ struct dep_stack stack;
+
/* for choice groups start the check with main choice symbol */
+ dep_stack_insert(&stack, sym);
prop = sym_get_choice_prop(sym);
sym2 = sym_check_deps(prop_get_symbol(prop));
+ dep_stack_remove();
} else if (sym_is_choice(sym)) {
sym2 = sym_check_choice_deps(sym);
} else {
@@ -900,14 +1018,8 @@ struct symbol *sym_check_deps(struct symbol *sym)
sym->flags &= ~SYMBOL_CHECK;
}

- if (sym2) {
- fprintf(stderr, " -> %s", sym->name ? sym->name : "<choice>");
- if (sym2 == sym) {
- fprintf(stderr, "\n");
- zconfnerrs++;
- sym2 = NULL;
- }
- }
+ if (sym2 && sym2 == sym)
+ sym2 = NULL;

return sym2;
}
--
1.6.0.6

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