Index: clang/docs/analyzer/user-docs.rst
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--- clang/docs/analyzer/user-docs.rst
+++ clang/docs/analyzer/user-docs.rst
@@ -6,4 +6,5 @@
 .. toctree::
    :maxdepth: 2
 
+   user-docs/Configuration
    user-docs/CrossTranslationUnit
Index: clang/docs/analyzer/user-docs/Configuration.rst
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--- /dev/null
+++ clang/docs/analyzer/user-docs/Configuration.rst
@@ -0,0 +1,86 @@
+=============
+Configuration
+=============
+
+The analyzer can be configured with a wide variety of options and switches.
+One can fine-tune its behavior by passing these options as the
+``-analyzer-config`` command line parameter to the analyzer frontend action.
+For the complete list of the supported option list run this command:
+
+.. code-block:: bash
+
+  $ clang -cc1 -analyze -analyzer-config-help
+
+.. contents::
+   :local:
+
+Flexible array member modeling
+______________________________
+
+In C struct data types may end with a **flexible array member** with no
+specificed size:
+
+.. code-block:: cpp
+
+  struct vectord {
+      short len;    // there must be at least one other data member
+      double arr[]; // the flexible array member must be last
+      // The compiler may reserve extra padding space here, like it can between struct members
+  };
+
+  // ...
+
+  struct vectord *vector = malloc(sizeof(struct vectord) + n * sizeof(double));
+  vector->len = n;
+  for (int i = 0; i < vector->len; i++)
+      vector->arr[i] = ...;
+
+This pattern is widely used to spare an extra allocation and a pointer
+indirection thus gaining better cache locality.
+Source: `Wikipedia <https://en.wikipedia.org/wiki/Flexible_array_member>`_
+
+----
+
+There are multiple forms of FAMs in the wild:
+
+- Form 1 - Incomplete array member:
+
+  .. code-block:: cpp
+
+    struct Foo {
+      char field1;
+      int my_fam[]; // no size!
+    };
+
+- Form 2 - Constant array member with size 0:
+
+  .. code-block:: cpp
+
+    struct Foo {
+      char field1;
+      int my_fam[0]; // zero size!
+    };
+
+- Form 3 - Constant array member with size 1:
+
+  .. code-block:: cpp
+
+    struct Foo {
+      char field1;
+      int my_fam[1]; // single element!
+    };
+
+We recommend not using FAMs at all. If you really need them, stick to using
+the *first form* mentioned in the list - using an incomplete array member
+declaration. It will deliver the intent of the programmer that the size
+of the array is indeed unknown.
+
+*Form 2* is also discouraged, since not all compilers might support it.
+*Form 3* is considered harmful! It's highly likely that any use of that form
+would result in undefined behavior. The compiler has the right to compile the
+binary under the assumption that the array has exactly one element.
+
+By default, the Clang Static Analyzer will consider only *form 1* and *form 2*
+as *flexible array members*. If the project under analysis uses FAMs of
+*form 3*, then consider enabling the
+``consider-single-element-arrays-as-flexible-array-members=true`` config option.