[analyzer] Disable graph-trim-interval by default

Because this hack is responsible for use-after-free errors that can
trigger assertion failures, as reported e.g. in the github issue
#105512

Disabling this performance optimization can cause severe slowdowns (up
to +200% runtime) on a few specific translation units, but its effects
are barely significant when they are averaged over a whole project: even
on projects that are "severely affected" the slowdowns are <20 seconds.

If someone happens to be heavily affected by this performance loss (and
doesn't fear the crashes) they can re-enable ExplodedNode reclamation by
passing -analyzer-option graph-trim-interval=1000 (the old default) to
the analyzer.

This commit is a temporary workaround to eliminate the crashes ASAP; in
addition to this, we're also working to develop a long-term solution
that can hopefully remove 'graph-trim-interval' altogether and replace
it with different solutions that guarantee a good runtime without
breaking the invariants of the ExplodedGraph. (It would be much easier
to reason about the execution paths if we didn't have to think about the
case that some nodes can just disappear.)

Author: NagyDonat

clang/include/clang/StaticAnalyzer/Core/AnalyzerOptions.def

@@ -393,9 +393,11 @@ ANALYZER_OPTION(
 
 ANALYZER_OPTION(
     unsigned, GraphTrimInterval, "graph-trim-interval",
-    "How often nodes in the ExplodedGraph should be recycled to save memory. "
-    "To disable node reclamation, set the option to 0.",
-    1000)
+    "[DEPRECATED] When set to a number N > 0, this enables reclamation of "
+    "'unimportant' nodes in the ExplodedGraph once per N node creation steps. "
+    "This reduces the memory usage, but can cause use-after-free errors or "
+    "crashes, so will be phased out.",
+    0)
 
 ANALYZER_OPTION(
     unsigned, MinCFGSizeTreatFunctionsAsLarge,

clang/test/Analysis/analyzer-config.c

@@ -84,7 +84,7 @@
 // CHECK-NEXT: experimental-enable-naive-ctu-analysis = false
 // CHECK-NEXT: exploration_strategy = unexplored_first_queue
 // CHECK-NEXT: faux-bodies = true
-// CHECK-NEXT: graph-trim-interval = 1000
+// CHECK-NEXT: graph-trim-interval = 0
 // CHECK-NEXT: ignore-bison-generated-files = true
 // CHECK-NEXT: ignore-flex-generated-files = true
 // CHECK-NEXT: inline-lambdas = true