Remove --enable-debug configure flag

With --enable-debug, compiler flags include -g -O2, i.e. with debugging, with optimisations.
Without --enable-debug, compiler flags include -g -O2 -DNDEBUG

-g -O2 are defaults according to AC_PROG_CXX

The macro NDEBUG has a small performance impact (less than 1%), but can
put issues to light. It is beneficial to have assertions always enabled.

Remove the flag, and let the user override CFLAGS/CXXFLAGS if he wishes
to. This is documented in INSTALL.

2 files changed, 15 insertions, 20 deletions

diff --git a/INSTALL b/INSTALL
index 464eb57..7b18d2c 100644
--- a/INSTALL
+++ b/INSTALL
@@ -27,16 +27,14 @@ The configure script can be launch with a variety of options:
                         output and remotecontrol.
  --disable-output-uhd   Disable the binding to the UHD driver for USRPs
  --enable-fast-math     Compile using the -ffast-math option that gives a substantial
-                        speedup at the cost of correctness.
+                        speedup at the cost of floating point correctness.
  --disable-native       Do not compile ODR-DabMod with -march=native compiler option.
                         This is meant for distribution package maintainers who want to
                         use their own march option, and for people running into compilation
                         issues due to -march=native. (e.g. GCC bug 70132 on ARM systems)
  --enable-edi           Enable the EDI input.
 
-Debugging options: You should not enable debug if you need good performance.
-By default, debug is disabled.
- --enable-debug         Do not compile with debugging, and enable optimisations
+Debugging options: You should not enable any debug option if you need good performance.
  --enable-trace         Create debugging files for each DSP block for data analysis
 
 For more information, call:
@@ -54,10 +52,21 @@ Tricks for best performance:
     * Do not use --disable-native
     * Use --enable-fast-math
     * Add -O3 to compiler flags
+    * Disable assertions with -DNDEBUG
 
 Applying all together:
 
-    % CFLAGS="-O3" CXXFLAGS="-O3" ./configure --enable-fast-math
+    % ./configure CFLAGS="-O3 -DNDEBUG" CXXFLAGS="-O3 -DNDEBUG" --enable-fast-math
+
+Checking for memory usage issues
+--------------------------------
+If your compiler supports it, you can enable the address sanitizer to check for memory
+issues:
+
+    % ./configure CFLAGS="-fsanitize=address -g -O2" CXXFLAGS="-fsanitize=address -g -O2"
+
+The resulting binary will be instrumented with additional memory checks, which have a
+measurable overhead. Please report if you get warnings or errors when using the sanitizer.
 
 Nearly as simple install procedure using repository:
 ====================================================
diff --git a/configure.ac b/configure.ac
index adf981b..e5221da 100644
--- a/configure.ac
+++ b/configure.ac
@@ -37,31 +37,21 @@ AC_PROG_INSTALL
 AX_CXX_COMPILE_STDCXX_11(noext,mandatory)
 
 EXTRA=""
-AC_ARG_ENABLE([debug],
-        [AS_HELP_STRING([--enable-debug], [Enable debugger symbols])],
-        [], [enable_debug=no])
 AC_ARG_ENABLE([prof],
         [AS_HELP_STRING([--enable-prof], [Enable profiling])],
         [], [enable_prof=no])
 AC_ARG_ENABLE([fast-math],
         [AS_HELP_STRING([--enable-fast-math], [Set -ffast-math])],
         [], [enable_fast_math=no])
-AC_ARG_WITH([debug-malloc],
-        [AS_HELP_STRING([--with-debug-malloc[=no|yes|duma|efence|...]],
-            [Add malloc debugger support])],
-        [], [with_debug_malloc=no])
 AC_ARG_ENABLE([trace],
         [AS_HELP_STRING([--enable-trace], [Enable trace output])],
         [], [enable_trace=no])
-
 AC_ARG_ENABLE([zeromq],
         [AS_HELP_STRING([--disable-zeromq], [Disable ZeroMQ input, output and remote control])],
         [], [enable_zeromq=yes])
-
 AC_ARG_ENABLE([edi],
         [AS_HELP_STRING([--enable-edi], [Enable EDI input])],
         [], [enable_edi=no])
-
 AC_ARG_ENABLE([native],
         [AS_HELP_STRING([--disable-native], [Do not compile with -march=native])],
         [], [enable_native=yes])
@@ -93,10 +83,6 @@ AS_IF([test "x$enable_zeromq" = "xyes"],
 AS_IF([test "x$enable_zeromq" = "xyes"],
         [AC_DEFINE(HAVE_ZEROMQ, [1], [Define if ZeroMQ is enabled])])
 
-AS_IF([test "x$enable_debug" = "xno"],
-        [EXTRA="$EXTRA -DNDEBUG"],
-        [EXTRA="$EXTRA"])
-
 AS_IF([test "x$enable_prof" != "xno"],
         [EXTRA="$EXTRA -pg"])
 
@@ -218,7 +204,7 @@ echo
 echo
 enabled=""
 disabled=""
-for feat in with_debug_malloc supports_march_native enable_fast_math
+for feat in supports_march_native enable_fast_math
 do
     eval var=\$$feat
     AS_IF([test "x$var" != "xno"],