Add Valgrind stack instrumentation

Our coroutine system can make debugging memory issues harder by not
following a standard stack allocation system.  We can get around this by
using valgrind's built-in stack instrumentation.  Each coroutine
registers a stack allocation allowing memcheck to recognize when
accesses are bounded.

CMakeLists.txt

@@ -125,6 +125,10 @@ option( KICAD_BUILD_PARALLEL_CL_MP
     "Build in parallel using the /MP compiler option (default OFF for safety reasons)"
     OFF )
 
+option( KICAD_USE_VALGRIND
+    "Build KiCad with valgrind stack tracking enabled."
+    OFF )
+
 # when option KICAD_SCRIPTING OR KICAD_SCRIPTING_MODULES is enabled:
 # PYTHON_EXECUTABLE can be defined when invoking cmake
 # ( use -DPYTHON_EXECUTABLE=<python path>/python.exe or python2 )
@@ -161,6 +165,10 @@ set( CMAKE_POSITION_INDEPENDENT_CODE ON )
 set(CMAKE_CXX_STANDARD 14)
 set(CMAKE_CXX_STANDARD_REQUIRED ON)
 
+# Enable additional valgrind instrumentation for stack tracking in libcontext
+if( KICAD_USE_VALGRIND )
+    add_definitions( -DKICAD_USE_VALGRIND )
+endif()
 
 # CMP0063: CMake < 3.3 does not handle hidden visibility for static libraries,
 # and 3.3 is backwards compatible when the minimum version is smaller than 3.3.

include/tool/coroutine.h

@@ -31,6 +31,10 @@
 
 #include <type_traits>
 
+#ifdef KICAD_USE_VALGRIND
+#include <valgrind/valgrind.h>
+#endif
+
 #include <system/libcontext.h>
 #include <memory>
 
@@ -65,8 +69,8 @@ private:
     {
         enum
         {
-            FROM_ROOT,      // a stub was called/a corutine was resumed from the main-stack context
-            FROM_ROUTINE,   // a stub was called/a coroutine was resumed fron a coroutine context
+            FROM_ROOT,      // a stub was called/a coroutine was resumed from the main-stack context
+            FROM_ROUTINE,   // a stub was called/a coroutine was resumed from a coroutine context
             CONTINUE_AFTER_ROOT // a function sent a request to invoke a function on the main
                                 // stack context
         } type; // invocation type
@@ -140,11 +144,17 @@ public:
         m_callContext( nullptr ),
         m_callee( nullptr ),
         m_retVal( 0 )
+#ifdef KICAD_USE_VALGRIND
+        ,valgrind_stack( 0 )
+#endif
     {
     }
 
     ~COROUTINE()
     {
+#ifdef KICAD_USE_VALGRIND
+        VALGRIND_STACK_DEREGISTER( valgrind_stack );
+#endif
     }
 
 public:
@@ -306,6 +316,10 @@ private:
 
         // correct the stack size
         stackSize -= size_t( ( (ptrdiff_t) m_stack.get() + stackSize ) - (ptrdiff_t) sp );
+
+#ifdef KICAD_USE_VALGRIND
+        valgrind_stack = VALGRIND_STACK_REGISTER( sp, m_stack.get() );
+#endif
         #endif
 
         m_callee = libcontext::make_fcontext( sp, stackSize, callerStub );
@@ -389,6 +403,10 @@ private:
     CALLEE_STORAGE m_callee;
 
     ReturnType m_retVal;
+
+#ifdef KICAD_USE_VALGRIND
+    uint32_t valgrind_stack;
+#endif
 };
 
 #endif