C++: Implement compilation_build_mode

cpp/downgrades/f0156f5f88ab5967c79162012c20f30600ca5ebf/upgrade.properties

@@ -0,0 +1,3 @@
+description: Implement compilation_build_mode/2
+compatibility: full
+compilation_build_mode.rel: delete

cpp/ql/lib/semmle/code/cpp/Compilation.qll

@@ -112,4 +112,7 @@ class Compilation extends @compilation {
    * termination, but crashing due to something like a segfault is not.
    */
   predicate normalTermination() { compilation_finished(this, _, _) }
+
+  /** Holds if this compilation was compiled using the "none" build mode. */
+  predicate buildModeNone() { compilation_build_mode(this, 0) }
 }

cpp/ql/lib/semmlecode.cpp.dbscheme

@@ -46,6 +46,22 @@ compilation_args(
     string arg : string ref
 );
 
+/**
+ * Optionally, record the build mode for each compilation.
+ */
+compilation_build_mode(
+    unique int id : @compilation ref,
+    int mode : int ref
+);
+
+/*
+case @compilation_build_mode.mode of
+  0 = @build_mode_none
+| 1 = @build_mode_manual
+| 2 = @build_mode_auto
+;
+*/
+
 /**
  * The source files that are compiled by a compiler invocation.
  * If `id` is for the compiler invocation