Add new configure argument --optimize-for-size

Uses -Os for GCC/Clang/ICC, /O1 for MSVC.

Might be used in the future to control compile time features also
(eg using a large precomputed table, vs not). Does not have any
influence on module selection, just informs the build that a smaller
binary is preferable.

[ci skip]

5 files changed, 17 insertions, 1 deletions

diff --git a/configure.py b/configure.py
index 57f24c8f3..9122b38f0 100755
--- a/configure.py
+++ b/configure.py
@@ -287,6 +287,10 @@ def process_command_line(args):
                            action='store_false',
                            help='disable building shared library')
 
+    build_group.add_option('--optimize-for-size', dest='optimize_for_size',
+                           action='store_true', default=False,
+                           help='optimize for code size')
+
     build_group.add_option('--no-optimizations', dest='no_optimizations',
                            action='store_true', default=False,
                            help='disable all optimizations (for debugging)')
@@ -853,6 +857,7 @@ class CompilerInfo(object):
                         'compile_flags': '',
                         'debug_info_flags': '',
                         'optimization_flags': '',
+                        'size_optimization_flags': '',
                         'coverage_flags': '',
                         'sanitizer_flags': '',
                         'shared_flags': '',
@@ -963,7 +968,14 @@ class CompilerInfo(object):
                 yield self.debug_info_flags
 
             if not options.no_optimizations:
-                yield self.optimization_flags
+                if options.optimize_for_size:
+                    if self.size_optimization_flags != '':
+                        yield self.size_optimization_flags
+                    else:
+                        logging.warning("No size optimization flags set for current compiler")
+                        yield self.optimization_flags
+                else:
+                    yield self.optimization_flags
 
             def submodel_fixup(flags, tup):
                 return tup[0].replace('SUBMODEL', flags.replace(tup[1], ''))
diff --git a/src/build-data/cc/clang.txt b/src/build-data/cc/clang.txt
index 8c5baf7ca..c4a85658f 100644
--- a/src/build-data/cc/clang.txt
+++ b/src/build-data/cc/clang.txt
@@ -16,6 +16,7 @@ maintainer_warning_flags "-Qunused-arguments -Werror -Wno-error=unused-parameter
 compile_flags "-c"
 debug_info_flags "-g"
 optimization_flags "-O3"
+size_optimization_flags "-Os"
 #sanitizer_flags "-fsanitize=address,undefined -fsanitize-coverage=edge,indirect-calls,8bit-counters -fno-sanitize-recover=undefined"
 sanitizer_flags "-fsanitize=address,undefined"
 
diff --git a/src/build-data/cc/gcc.txt b/src/build-data/cc/gcc.txt
index b086583ff..b88454ce6 100644
--- a/src/build-data/cc/gcc.txt
+++ b/src/build-data/cc/gcc.txt
@@ -17,6 +17,7 @@ maintainer_warning_flags "-Wold-style-cast -Wsuggest-override -Wshadow -Werror -
 compile_flags "-c"
 debug_info_flags "-g"
 optimization_flags "-O3"
+size_optimization_flags "-Os"
 
 shared_flags "-fPIC"
 coverage_flags "--coverage"
diff --git a/src/build-data/cc/icc.txt b/src/build-data/cc/icc.txt
index 084d2a4f2..f1b7e5a15 100644
--- a/src/build-data/cc/icc.txt
+++ b/src/build-data/cc/icc.txt
@@ -10,6 +10,7 @@ add_lib_option -l
 compile_flags "-c"
 debug_info_flags "-g"
 optimization_flags "-O2"
+size_optimization_flags "-Os"
 
 lang_flags "-std=c++0x"
 warning_flags "-w1"
diff --git a/src/build-data/cc/msvc.txt b/src/build-data/cc/msvc.txt
index 8231c0429..c1b820b91 100644
--- a/src/build-data/cc/msvc.txt
+++ b/src/build-data/cc/msvc.txt
@@ -11,6 +11,7 @@ add_lib_option ""
 compile_flags "/nologo /c"
 
 optimization_flags "/O2"
+size_optimization_flags "/O1"
 
 # for debug info in the object file:
 #debug_info_flags "/Z7"