add --enable-optimized=debug

This will use -Og with GCC/Clang instead of -O0, which should make
unittests run faster without (hopefully) breaking anything related
to debugging. This is primarily meant to Jenkins builds, where
debug info is rarely needed (backtraces for unittest crashes AFAICT).

This can be also used to make LO itself run faster when developing,
but I personally do not find it worth it (with Clang and full PCH
this makes starmath build take about 70% longer, although presumably
for non-PCH builds the relative increase will be smaller).

Change-Id: I198d0759ebca94c90be662e02e0f1281a24d1d70
Reviewed-on: https://gerrit.libreoffice.org/c/core/+/88917
Reviewed-by: Michael Stahl <michael.stahl@cib.de>
Reviewed-by: Luboš Luňák <l.lunak@collabora.com>
Tested-by: Jenkins

config_host.mk.in

@@ -177,6 +177,7 @@ export ENABLE_OOENV=@ENABLE_OOENV@
 export ENABLE_OPENGL_TRANSITIONS=@ENABLE_OPENGL_TRANSITIONS@
 export ENABLE_OPENGL_CANVAS=@ENABLE_OPENGL_CANVAS@
 export ENABLE_OPTIMIZED=@ENABLE_OPTIMIZED@
+export ENABLE_OPTIMIZED_DEBUG=@ENABLE_OPTIMIZED_DEBUG@
 export ENABLE_PCH=@ENABLE_PCH@
 export ENABLE_PDFIMPORT=@ENABLE_PDFIMPORT@
 export ENABLE_PDFIUM=@ENABLE_PDFIUM@

configure.ac

@@ -1194,10 +1194,11 @@ libo_FUZZ_ARG_ENABLE(symbols,
          Example: --enable-symbols="all -sw/ -Library_sc".]))
 
 libo_FUZZ_ARG_ENABLE(optimized,
-    AS_HELP_STRING([--disable-optimized],
+    AS_HELP_STRING([--enable-optimized=<yes/no/debug>],
         [Whether to compile with optimization flags.
          By default, disabled for --enable-debug and --enable-dbgutil, enabled
-         otherwise.]))
+         otherwise. Using 'debug' will try to use only optimizations that should
+         not interfere with debugging.]))
 
 libo_FUZZ_ARG_ENABLE(runtime-optimizations,
     AS_HELP_STRING([--disable-runtime-optimizations],
@@ -4204,6 +4205,8 @@ if test -n "$with_android_ndk" -a \( -n "$ENABLE_SYMBOLS" -o -n "$ENABLE_DEBUG"
     fi
 fi
 
+ENABLE_OPTIMIZED=
+ENABLE_OPTIMIZED_DEBUG=
 AC_MSG_CHECKING([whether to compile with optimization flags])
 if test -z "$enable_optimized"; then
     if test -n "$ENABLE_DEBUG$ENABLE_DBGUTIL"; then
@@ -4212,14 +4215,33 @@ if test -z "$enable_optimized"; then
         enable_optimized=yes
     fi
 fi
-if test "$enable_optimized" != no; then
+if test "$enable_optimized" = yes; then
     ENABLE_OPTIMIZED=TRUE
     AC_MSG_RESULT([yes])
+elif test "$enable_optimized" = debug; then
+    ENABLE_OPTIMIZED_DEBUG=TRUE
+    AC_MSG_RESULT([yes (debug)])
+    HAVE_GCC_OG=
+    if test "$GCC" = "yes"; then
+        AC_MSG_CHECKING([whether $CC_BASE supports -Og])
+        save_CFLAGS=$CFLAGS
+        CFLAGS="$CFLAGS -Werror -Og"
+        AC_LINK_IFELSE([AC_LANG_PROGRAM([[]], [[ return 0; ]])],[ HAVE_GCC_OG=TRUE ],[])
+        CFLAGS=$save_CFLAGS
+        if test "$HAVE_GCC_OG" = "TRUE"; then
+            AC_MSG_RESULT([yes])
+        else
+            AC_MSG_RESULT([no])
+        fi
+    fi
+    if test -z "$HAVE_GCC_OG"; then
+        AC_MSG_ERROR([The compiler does not support optimizations suitable for debugging.])
+    fi
 else
-    ENABLE_OPTIMIZED=
     AC_MSG_RESULT([no])
 fi
 AC_SUBST(ENABLE_OPTIMIZED)
+AC_SUBST(ENABLE_OPTIMIZED_DEBUG)
 
 #
 # determine CPUNAME, OS, ...

solenv/gbuild/LinkTarget.mk

@@ -44,7 +44,11 @@ gb_LinkTarget__symbols_enabled = \
             $(filter $(1),$(ENABLE_SYMBOLS_FOR))))
 
 # debug flags, if the LinkTarget is named in the list of libraries of ENABLE_SYMBOLS_FOR
-gb_LinkTarget__get_debugflags=$(if $(ENABLE_OPTIMIZED),$(gb_COMPILEROPTFLAGS),$(gb_COMPILERNOOPTFLAGS)) $(if $(call gb_LinkTarget__symbols_enabled,$(1)),$(gb_DEBUGINFO_FLAGS))
+gb_LinkTarget__get_debugflags= \
+$(if $(ENABLE_OPTIMIZED),$(gb_COMPILEROPTFLAGS), \
+$(if $(ENABLE_OPTIMIZED_DEBUG),$(gb_COMPILERDEBUGOPTFLAGS), \
+$(gb_COMPILERNOOPTFLAGS))) \
+$(if $(call gb_LinkTarget__symbols_enabled,$(1)),$(gb_DEBUGINFO_FLAGS))
 
 # similar for LDFLAGS, use linker optimization flags in non-debug case,
 # but moreover strip debug from libraries for which debuginfo is not wanted

solenv/gbuild/platform/com_GCC_defs.mk

@@ -201,6 +201,7 @@ gb_PrecompiledHeader_EXCEPTIONFLAGS := $(gb_LinkTarget_EXCEPTIONFLAGS)
 
 # optimization level
 gb_COMPILERNOOPTFLAGS := -O0 -fstrict-aliasing -fstrict-overflow
+gb_COMPILERDEBUGOPTFLAGS := -Og
 
 ifeq ($(OS),ANDROID)
 gb_DEBUGINFO_FLAGS=-glldb

solenv/gbuild/platform/com_MSC_defs.mk

@@ -265,6 +265,7 @@ gb_LINKER_DEBUGINFO_FLAGS :=
 
 gb_COMPILEROPTFLAGS := -O2 -Oy-
 gb_COMPILERNOOPTFLAGS := -Od
+gb_COMPILERDEBUGOPTFLAGS :=
 
 ifeq ($(gb_FULLDEPS),$(true))
 gb_COMPILERDEPFLAGS := -showIncludes