Add --incremental-analysis flag

Summary:
Add a flag to enable incremental diff analysis, where old summaries are not recomputed unless necessary

The implementation for this flag will follow

Reviewed By: ngorogiannis

Differential Revision: D16222865

fbshipit-source-id: e7e225a87

infer/man/man1/infer-full.txt

@@ -1395,6 +1395,10 @@ INTERNAL OPTIONS
        --icfg-dotty-outfile-reset
            Cancel the effect of --icfg-dotty-outfile.
 
+       --incremental-analysis
+           Activates: [EXPERIMENTAL] Use incremental analysis for changed
+           files (Conversely: --no-incremental-analysis)
+
        --iphoneos-target-sdk-version-path-regex-reset
            Set --iphoneos-target-sdk-version-path-regex to the empty list.
 

infer/src/base/Config.ml

@@ -2343,6 +2343,11 @@ and use_cost_threshold =
     "Emit costs issues by comparing costs with a set threshold"
 
 
+and incremental_analysis =
+  CLOpt.mk_bool ~long:"incremental-analysis" ~default:false
+    "[EXPERIMENTAL] Use incremental analysis for changed files"
+
+
 and version =
   let var = ref `None in
   CLOpt.mk_set var `Full ~deprecated:["version"] ~long:"version"
@@ -3176,6 +3181,8 @@ and unsafe_malloc = !unsafe_malloc
 
 and use_cost_threshold = !use_cost_threshold
 
+and incremental_analysis = !incremental_analysis
+
 and worklist_mode = !worklist_mode
 
 and write_dotty = !write_dotty

infer/src/base/Config.mli

@@ -195,6 +195,9 @@ val unsafe_unret : string
 
 val use_cost_threshold : bool
 
+(* Suppress unused value warning because the incremental analysis feature is not yet complete *)
+val incremental_analysis : bool [@@warning "-32"]
+
 val weak : string
 
 val whitelisted_cpp_classes : string list