analyzer: remove -Wanalyzer-use-of-uninitialized-value for GCC 10

From what I can tell -Wanalyzer-use-of-uninitialized-value has not
yet found a true diagnostic in real-world code, and seems to be
particularly susceptible to false positives.  These relate to bugs in
the region_model code.

For GCC 10 it seems best to remove this warning, which this patch does.
Internally it also removes POISON_KIND_UNINIT.

I'm working on a rewrite of the region_model code for GCC 11 that I
hope will fix these issues, and allow this warning to be reintroduced.

gcc/analyzer/ChangeLog:
	PR analyzer/94447
	PR analyzer/94639
	PR analyzer/94732
	PR analyzer/94754
	* analyzer.opt (Wanalyzer-use-of-uninitialized-value): Delete.
	* program-state.cc (selftest::test_program_state_dumping): Update
	expected dump result for removal of "uninit".
	* region-model.cc (poison_kind_to_str): Delete POISON_KIND_UNINIT
	case.
	(root_region::ensure_stack_region): Initialize stack with null
	svalue_id rather than with a typeless POISON_KIND_UNINIT value.
	(root_region::ensure_heap_region): Likewise for the heap.
	(region_model::dump_summary_of_rep_path_vars): Remove
	summarization of uninit values.
	(region_model::validate): Remove check that the stack has a
	POISON_KIND_UNINIT value.
	(poisoned_value_diagnostic::emit): Remove POISON_KIND_UNINIT
	case.
	(poisoned_value_diagnostic::describe_final_event): Likewise.
	(selftest::test_dump): Update expected dump result for removal of
	"uninit".
	(selftest::test_svalue_equality): Remove "uninit" and "freed".
	* region-model.h (enum poison_kind): Remove POISON_KIND_UNINIT.

gcc/ChangeLog:
	PR analyzer/94447
	PR analyzer/94639
	PR analyzer/94732
	PR analyzer/94754
	* doc/invoke.texi (Static Analyzer Options): Remove
	-Wanalyzer-use-of-uninitialized-value.
	(-Wno-analyzer-use-of-uninitialized-value): Remove item.

gcc/testsuite/ChangeLog:
	PR analyzer/94447
	PR analyzer/94639
	PR analyzer/94732
	PR analyzer/94754
	* gcc.dg/analyzer/data-model-1.c: Mark "use of uninitialized
	value" warnings as xfail for now.
	* gcc.dg/analyzer/data-model-5b.c: Remove uninitialized warning.
	* gcc.dg/analyzer/pr94099.c: Mark "uninitialized" warning as xfail
	for now.
	* gcc.dg/analyzer/pr94447.c: New test.
	* gcc.dg/analyzer/pr94639.c: New test.
	* gcc.dg/analyzer/pr94732.c: New test.
	* gcc.dg/analyzer/pr94754.c: New test.
	* gcc.dg/analyzer/zlib-6.c: Mark "uninitialized" warning as xfail
	for now.

1 files changed, 6 insertions, 8 deletions

diff --git a/gcc/analyzer/program-state.cc b/gcc/analyzer/program-state.cc
index 43396c6..1a5843b 100644
--- a/gcc/analyzer/program-state.cc
+++ b/gcc/analyzer/program-state.cc
@@ -1449,23 +1449,21 @@ test_program_state_dumping ()
   ASSERT_DUMP_EQ
     (s, ext_state, false,
      "rmodel: r0: {kind: `root', parent: null, sval: null}\n"
-     "|-heap: r1: {kind: `heap', parent: r0, sval: sv0}\n"
-     "|  |: sval: sv0: {poisoned: uninit}\n"
+     "|-heap: r1: {kind: `heap', parent: r0, sval: null}\n"
      "|  `-r2: {kind: `symbolic', parent: r1, sval: null, possibly_null: true}\n"
      "`-globals: r3: {kind: `globals', parent: r0, sval: null, map: {`p': r4}}\n"
-     "  `-`p': r4: {kind: `primitive', parent: r3, sval: sv1, type: `void *'}\n"
-     "    |: sval: sv1: {type: `void *', &r2}\n"
+     "  `-`p': r4: {kind: `primitive', parent: r3, sval: sv0, type: `void *'}\n"
+     "    |: sval: sv0: {type: `void *', &r2}\n"
      "    |: type: `void *'\n"
      "svalues:\n"
-     "  sv0: {poisoned: uninit}\n"
-     "  sv1: {type: `void *', &r2}\n"
+     "  sv0: {type: `void *', &r2}\n"
      "constraint manager:\n"
      "  equiv classes:\n"
      "  constraints:\n"
-     "malloc: {sv1: unchecked (`p')}\n");
+     "malloc: {sv0: unchecked (`p')}\n");
 
   ASSERT_DUMP_EQ (s, ext_state, true,
-		  "rmodel: p: &r2 malloc: {sv1: unchecked (`p')}");
+		  "rmodel: p: &r2 malloc: {sv0: unchecked (`p')}");
 }
 
 /* Verify that program_state::dump_to_pp works for string literals.  */