DataFlowSanitizer: Add a design doc paragraph on checking ABI consistency.
Differential Revision: http://llvm-reviews.chandlerc.com/D1443
git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@189055 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/docs/DataFlowSanitizerDesign.rst b/docs/DataFlowSanitizerDesign.rst
index 8f1cc68..32db88b 100644
--- a/docs/DataFlowSanitizerDesign.rst
+++ b/docs/DataFlowSanitizerDesign.rst
@@ -205,3 +205,16 @@
internally. This has the advantage of reducing the number of union operations
required when the return value label is known to be zero (i.e. ``discard``
functions, or ``functional`` functions with known unlabelled arguments).
+
+Checking ABI Consistency
+------------------------
+
+DFSan changes the ABI of each function in the module. This makes it possible
+for a function with the native ABI to be called with the instrumented ABI,
+or vice versa, thus possibly invoking undefined behavior. A simple way
+of statically detecting instances of this problem is to prepend the prefix
+"dfs$" to the name of each instrumented-ABI function.
+
+This will not catch every such problem; in particular function pointers passed
+across the instrumented-native barrier cannot be used on the other side.
+These problems could potentially be caught dynamically.