commit a3385dadcb0ffb53da32d2690c0ea8157e2419bd
author Gabe Black <gabeblack@google.com> Wed Aug 22 16:49:22 2018 -0700
committer Gabe Black <gabeblack@google.com> Fri Aug 24 18:15:09 2018 +0000
tree 9af7ab099183937a851be9124961e4c26f5e7374
parent f741bb7cdbdd6c2526be40fe1e03a705364ddf8d

base: If valgrind is available, tell it about Fiber stacks.

Valgrind can get confused when  switching stacks between different
Fibers. If valgrind (and its headers) are available, this change adds
calls to some hooks so valgrind knows where the new stacks are and
doesn't report a bunch of false positives.

Change-Id: I00aefe60372be6de7371dec29427d7182dbee7b6
Reviewed-on: https://gem5-review.googlesource.com/12227
Reviewed-by: Giacomo Travaglini <giacomo.travaglini@arm.com>
Reviewed-by: Daniel Carvalho <odanrc@yahoo.com.br>
Maintainer: Gabe Black <gabeblack@google.com>

SConstruct

diff --git a/SConstruct b/SConstruct
index 5209aa6..79522e4 100755
--- a/SConstruct
+++ b/SConstruct
@@ -783,6 +783,10 @@
     conf.CheckLibWithHeader('protobuf', 'google/protobuf/message.h',
                             'C++', 'GOOGLE_PROTOBUF_VERIFY_VERSION;')
 
+# Valgrind gets much less confused if you tell it when you're using
+# alternative stacks.
+main['HAVE_VALGRIND'] = conf.CheckCHeader('valgrind/valgrind.h')
+
 # If we have the compiler but not the library, print another warning.
 if main['PROTOC'] and not main['HAVE_PROTOBUF']:
     print(termcap.Yellow + termcap.Bold +
@@ -1012,8 +1016,8 @@
 # These variables get exported to #defines in config/*.hh (see src/SConscript).
 export_vars += ['USE_FENV', 'SS_COMPATIBLE_FP', 'TARGET_ISA', 'TARGET_GPU_ISA',
                 'CP_ANNOTATE', 'USE_POSIX_CLOCK', 'USE_KVM', 'USE_TUNTAP',
-                'PROTOCOL', 'HAVE_PROTOBUF', 'HAVE_PERF_ATTR_EXCLUDE_HOST',
-                'USE_PNG']
+                'PROTOCOL', 'HAVE_PROTOBUF', 'HAVE_VALGRIND',
+                'HAVE_PERF_ATTR_EXCLUDE_HOST', 'USE_PNG']
 
 ###################################################
 #

src/base/fiber.cc

diff --git a/src/base/fiber.cc b/src/base/fiber.cc
index f10f1fb..eac1d93 100644
--- a/src/base/fiber.cc
+++ b/src/base/fiber.cc
@@ -29,6 +29,10 @@
 
 #include "base/fiber.hh"
 
+#if HAVE_VALGRIND
+#include <valgrind/valgrind.h>
+#endif
+
 #include <cerrno>
 #include <cstring>
 
@@ -71,7 +75,11 @@
     link(primaryFiber()),
     stack(stack_size ? new uint8_t[stack_size] : nullptr),
     stackSize(stack_size), started(false), _finished(false)
-{}
+{
+#if HAVE_VALGRIND
+    valgrindStackId = VALGRIND_STACK_REGISTER(stack, stack + stack_size);
+#endif
+}
 
 Fiber::Fiber(Fiber *link, size_t stack_size) :
     link(link), stack(stack_size ? new uint8_t[stack_size] : nullptr),
@@ -81,6 +89,9 @@
 Fiber::~Fiber()
 {
     panic_if(stack && _currentFiber == this, "Fiber stack is in use.");
+#if HAVE_VALGRIND
+    VALGRIND_STACK_DEREGISTER(valgrindStackId);
+#endif
     delete [] stack;
 }
 

src/base/fiber.hh

diff --git a/src/base/fiber.hh b/src/base/fiber.hh
index 5f7285b..3d82075 100644
--- a/src/base/fiber.hh
+++ b/src/base/fiber.hh
@@ -44,6 +44,8 @@
 #include <cstddef>
 #include <cstdint>
 
+#include "config/have_valgrind.hh"
+
 /**
  * This class represents a fiber, which is a light weight sort of thread which
  * is cooperatively scheduled and runs sequentially with other fibers, swapping
@@ -106,6 +108,9 @@
     // The stack for this context, or a nullptr if allocated elsewhere.
     uint8_t *stack;
     size_t stackSize;
+#if HAVE_VALGRIND
+    unsigned valgrindStackId;
+#endif
 
     bool started;
     bool _finished;