[analyzer] Analysis: Silence checkers

Summary:
This patch introduces a new `analyzer-config` configuration:
`-analyzer-config silence-checkers`
which could be used to silence the given checkers.

It accepts a semicolon separated list, packed into quotation marks, e.g:
`-analyzer-config silence-checkers="core.DivideZero;core.NullDereference"`

It could be used to "disable" core checkers, so they model the analysis as
before, just if some of them are too noisy it prevents to emit reports.

This patch also adds support for that new option to the scan-build.
Passing the option `-disable-checker core.DivideZero` to the scan-build
will be transferred to `-analyzer-config silence-checkers=core.DivideZero`.

Reviewed By: NoQ, Szelethus

Differential Revision: https://reviews.llvm.org/D66042

llvm-svn: 369078

1 files changed, 15 insertions, 3 deletions

diff --git a/clang/tools/scan-build/bin/scan-build b/clang/tools/scan-build/bin/scan-build
index 903e19a2909..37c94d5ec36 100755
--- a/clang/tools/scan-build/bin/scan-build
+++ b/clang/tools/scan-build/bin/scan-build
@@ -57,6 +57,7 @@ my %Options = (
   KeepEmpty => 0,            # Don't remove output directory even with 0 results.
   EnableCheckers => {},
   DisableCheckers => {},
+  SilenceCheckers => {},
   Excludes => [],
   UseCC => undef,            # C compiler to use for compilation.
   UseCXX => undef,           # C++ compiler to use for compilation.
@@ -1742,9 +1743,15 @@ sub ProcessArgs {
     if ($arg eq "-disable-checker") {
       shift @$Args;
       my $Checker = shift @$Args;
-      # Store $NumArgs to preserve the order the checkers were disabled.
-      $Options{DisableCheckers}{$Checker} = $NumArgs;
-      delete $Options{EnableCheckers}{$Checker};
+      # Store $NumArgs to preserve the order the checkers are disabled/silenced.
+      # See whether it is a core checker to disable. That means we do not want
+      # to emit a report from that checker so we have to silence it.
+      if (index($Checker, "core") == 0) {
+        $Options{SilenceCheckers}{$Checker} = $NumArgs;
+      } else {
+        $Options{DisableCheckers}{$Checker} = $NumArgs;
+        delete $Options{EnableCheckers}{$Checker};
+      }
       next;
     }
 
@@ -1882,6 +1889,11 @@ foreach (sort { $Options{DisableCheckers}{$a} <=> $Options{DisableCheckers}{$b}
   # Push checkers in order they were disabled.
   push @AnalysesToRun, "-analyzer-disable-checker", $_;
 }
+foreach (sort { $Options{SilenceCheckers}{$a} <=> $Options{SilenceCheckers}{$b} }
+         keys %{$Options{SilenceCheckers}}) {
+  # Push checkers in order they were silenced.
+  push @AnalysesToRun, "-analyzer-config silence-checker", $_;
+}
 if ($Options{AnalyzeHeaders}) { push @AnalysesToRun, "-analyzer-opt-analyze-headers"; }
 if ($Options{AnalyzerStats}) { push @AnalysesToRun, '-analyzer-checker=debug.Stats'; }
 if ($Options{MaxLoop} > 0) { push @AnalysesToRun, "-analyzer-max-loop $Options{MaxLoop}"; }