Fix bug #552: disable EIGEN_GLIBC_MALLOC_ALREADY_ALIGNED when compiling with -fsanitize=address, and allow users to manually tell whether EIGEN_MALLOC_ALREADY_ALIGNED.

2 files changed, 11 insertions, 2 deletions

diff --git a/Eigen/src/Core/util/Memory.h b/Eigen/src/Core/util/Memory.h
index de6e8b271..2a1a20fac 100644
--- a/Eigen/src/Core/util/Memory.h
+++ b/Eigen/src/Core/util/Memory.h
@@ -19,6 +19,10 @@
 #ifndef EIGEN_MEMORY_H
 #define EIGEN_MEMORY_H
 
+#ifndef EIGEN_MALLOC_ALREADY_ALIGNED
+
+// Try to determine automatically if malloc is already aligned.
+
 // On 64-bit systems, glibc's malloc returns 16-byte-aligned pointers, see:
 //   http://www.gnu.org/s/libc/manual/html_node/Aligned-Memory-Blocks.html
 // This is true at least since glibc 2.8.
@@ -27,7 +31,7 @@
 // page 114, "[The] LP64 model [...] is used by all 64-bit UNIX ports" so it's indeed
 // quite safe, at least within the context of glibc, to equate 64-bit with LP64.
 #if defined(__GLIBC__) && ((__GLIBC__>=2 && __GLIBC_MINOR__ >= 8) || __GLIBC__>2) \
- && defined(__LP64__)
+ && defined(__LP64__) && ! defined( __SANITIZE_ADDRESS__ )
   #define EIGEN_GLIBC_MALLOC_ALREADY_ALIGNED 1
 #else
   #define EIGEN_GLIBC_MALLOC_ALREADY_ALIGNED 0
@@ -52,6 +56,8 @@
   #define EIGEN_MALLOC_ALREADY_ALIGNED 0
 #endif
 
+#endif
+
 #if ((defined __QNXNTO__) || (defined _GNU_SOURCE) || ((defined _XOPEN_SOURCE) && (_XOPEN_SOURCE >= 600))) \
  && (defined _POSIX_ADVISORY_INFO) && (_POSIX_ADVISORY_INFO > 0)
   #define EIGEN_HAS_POSIX_MEMALIGN 1
diff --git a/doc/PreprocessorDirectives.dox b/doc/PreprocessorDirectives.dox
index f731b5628..eedd5524a 100644
--- a/doc/PreprocessorDirectives.dox
+++ b/doc/PreprocessorDirectives.dox
@@ -30,7 +30,7 @@ are doing.
    initialized to zero, as are new entries in matrices and arrays after resizing. Not defined by default.
  - \b EIGEN_INITIALIZE_MATRICES_BY_NAN - if defined, all entries of newly constructed matrices and arrays are
    initialized to NaN, as are new entries in matrices and arrays after resizing. This option is especially
-   useful for debugging purpose, though a memory tool like <a href="http://valgrind.org/">valgring</a> is
+   useful for debugging purpose, though a memory tool like <a href="http://valgrind.org/">valgrind</a> is
    preferable. Not defined by default.
  - \b EIGEN_NO_AUTOMATIC_RESIZING - if defined, the matrices (or arrays) on both sides of an assignment 
    <tt>a = b</tt> have to be of the same size; otherwise, %Eigen automatically resizes \c a so that it is of
@@ -55,6 +55,9 @@ run time. However, these assertions do cost time and can thus be turned off.
 
 \section TopicPreprocessorDirectivesPerformance Alignment, vectorization and performance tweaking
 
+ - \b EIGEN_MALLOC_ALREADY_ALIGNED - Can be set to 0 or 1 to tell whether default system malloc already
+   returns aligned buffers. In not defined, then this information is automatically deduced from the compiler
+   and system preprocessor tokens.
  - \b EIGEN_DONT_ALIGN - disables alignment completely. %Eigen will not try to align its objects and does not
    expect that any objects passed to it are aligned. This will turn off vectorization. Not defined by default.
  - \b EIGEN_DONT_ALIGN_STATICALLY - disables alignment of arrays on the stack. Not defined by default, unless