Add assembler, macro-assembler and disassembler support for AArch32

Add support for the A32 and T32 instruction set architectures in
seperate a32 directories.

Note that this commit introduces aarch32 and aarch64 namespaces so
existing client code will need to be adjusted.

Refer to doc/getting-started-a32.md for an introduction.

Change-Id: Iaf3e5f496ec4e19d77d304128e6920daa4549e78

1 files changed, 69 insertions, 29 deletions

diff --git a/SConstruct b/SConstruct
index ea3b64b0..6807df24 100644
--- a/SConstruct
+++ b/SConstruct
@@ -89,7 +89,8 @@ options = {
       'CCFLAGS' : ['-DVIXL_DEBUG', '-O0']
       },
     'mode:release' : {
-      'CCFLAGS' : ['-O3']
+      'CCFLAGS' : ['-O3', '-fdata-sections', '-ffunction-sections'],
+      'LINKFLAGS' : ['-Wl,--gc-sections']
       },
     'simulator:on' : {
       'CCFLAGS' : ['-DVIXL_INCLUDE_SIMULATOR'],
@@ -158,9 +159,11 @@ options_influencing_build_path = ['mode', 'symbols', 'CXX', 'std', 'simulator']
 # Build helpers ----------------------------------------------------------------
 
 def RetrieveEnvironmentVariables(env):
-  for key in ['CC', 'CXX', 'CCFLAGS', 'CXXFLAGS', 'AR', 'RANLIB', 'LD']:
+  for key in ['CC', 'CXX', 'AR', 'RANLIB', 'LD']:
     if os.getenv(key): env[key] = os.getenv(key)
   if os.getenv('LD_LIBRARY_PATH'): env['LIBPATH'] = os.getenv('LD_LIBRARY_PATH')
+  if os.getenv('CCFLAGS'):
+    env.Append(CCFLAGS = os.getenv('CCFLAGS').split())
   if os.getenv('CXXFLAGS'):
     env.Append(CXXFLAGS = os.getenv('CXXFLAGS').split())
   if os.getenv('LINKFLAGS'):
@@ -210,6 +213,13 @@ def ConfigureEnvironmentForCompiler(env):
     if not using_clang3_4:
       env.Append(CPPFLAGS = ['-Wunreachable-code'])
 
+    env.Append(CPPFLAGS = ['-Wno-unreachable-code'])
+    env.Append(CPPFLAGS = ['-Wno-shorten-64-to-32'])
+    env.Append(CPPFLAGS = ['-Wno-missing-noreturn'])
+    env.Append(CPPFLAGS = ['-Wno-unused-private-field'])
+    env.Append(CPPFLAGS = ['-Wno-implicit-fallthrough'])
+    env.Append(CPPFLAGS = ['-Wno-sometimes-uninitialized'])
+
   # GCC 4.8 has a bug which produces a warning saying that an anonymous Operand
   # object might be used uninitialized:
   #   http://gcc.gnu.org/bugzilla/show_bug.cgi?id=57045
@@ -227,6 +237,12 @@ def ConfigureEnvironmentForCompiler(env):
   if 'std' not in env or env['std'] == 'c++98':
     env.Append(CPPFLAGS = ['-Wno-c++11-long-long'])
 
+  # The generated macro assembler contains uninitialized variables and
+  # GCC cannot prove that they are always initialised, even though it
+  # should.
+  if env['mode'] == 'release' and is_compiler('g++'):
+    env.Append(CPPFLAGS = ['-Wno-maybe-uninitialized'])
+
 
 def ConfigureEnvironment(env):
   RetrieveEnvironmentVariables(env)
@@ -261,8 +277,10 @@ def VIXLLibraryTarget(env):
   subprocess.check_call(["ln", "-s", build_dir, config.dir_build_latest])
   # Source files are in `src` and in `src/a64/`.
   variant_dir_vixl = PrepareVariantDir(join('src'), build_dir)
+  variant_dir_a32 = PrepareVariantDir(join('src', 'a32'), build_dir)
   variant_dir_a64 = PrepareVariantDir(join('src', 'a64'), build_dir)
   sources = [Glob(join(variant_dir_vixl, '*.cc')),
+             Glob(join(variant_dir_a32, '*.cc')),
              Glob(join(variant_dir_a64, '*.cc'))]
   return env.Library(join(build_dir, 'vixl'), sources)
 
@@ -281,45 +299,67 @@ top_level_targets.Add('', 'Build the VIXL library.')
 
 
 # The benchmarks.
-benchmark_names = util.ListCCFilesWithoutExt(config.dir_benchmarks)
-benchmarks_build_dir = PrepareVariantDir('benchmarks', TargetBuildDir(env))
-benchmark_targets = []
-for bench in benchmark_names:
-  prog = env.Program(join(benchmarks_build_dir, bench),
-                     join(benchmarks_build_dir, bench + '.cc'),
+a64_benchmark_names = util.ListCCFilesWithoutExt(config.dir_a64_benchmarks)
+a64_benchmarks_build_dir = PrepareVariantDir('benchmarks/a64', TargetBuildDir(env))
+a64_benchmark_targets = []
+for bench in a64_benchmark_names:
+  prog = env.Program(join(a64_benchmarks_build_dir, bench),
+                     join(a64_benchmarks_build_dir, bench + '.cc'),
                      LIBS=[libvixl])
-  benchmark_targets.append(prog)
-env.Alias('benchmarks', benchmark_targets)
-top_level_targets.Add('benchmarks', 'Build the benchmarks.')
+  a64_benchmark_targets.append(prog)
+env.Alias('a64_benchmarks', a64_benchmark_targets)
+top_level_targets.Add('a64_benchmarks', 'Build the benchmarks for AArch64.')
 
 
 # The examples.
-example_names = util.ListCCFilesWithoutExt(config.dir_examples)
-examples_build_dir = PrepareVariantDir('examples', TargetBuildDir(env))
-example_targets = []
-for example in example_names:
-  prog = env.Program(join(examples_build_dir, example),
-                     join(examples_build_dir, example + '.cc'),
+a64_example_names = util.ListCCFilesWithoutExt(config.dir_a64_examples)
+a64_examples_build_dir = PrepareVariantDir('examples/a64', TargetBuildDir(env))
+a64_example_targets = []
+for example in a64_example_names:
+  prog = env.Program(join(a64_examples_build_dir, example),
+                     join(a64_examples_build_dir, example + '.cc'),
                      LIBS=[libvixl])
-  example_targets.append(prog)
-env.Alias('examples', example_targets)
-top_level_targets.Add('examples', 'Build the examples.')
+  a64_example_targets.append(prog)
+env.Alias('a64_examples', a64_example_targets)
+top_level_targets.Add('a64_examples', 'Build the examples for AArch64.')
+a32_example_names = util.ListCCFilesWithoutExt(config.dir_a32_examples)
+a32_examples_build_dir = PrepareVariantDir('examples/a32', TargetBuildDir(env))
+a32_example_targets = []
+for example in a32_example_names:
+  prog = env.Program(join(a32_examples_build_dir, example),
+                     join(a32_examples_build_dir, example + '.cc'),
+                     LIBS=[libvixl])
+  a32_example_targets.append(prog)
+env.Alias('a32_examples', a32_example_targets)
+top_level_targets.Add('a32_examples', 'Build the examples for AArch32.')
 
 
 # The tests.
 test_build_dir = PrepareVariantDir('test', TargetBuildDir(env))
+test_objects = [env.Object(Glob(join(test_build_dir, '*.cc')))]
+
+test_a32_build_dir = PrepareVariantDir(join('test', 'a32'), TargetBuildDir(env))
+test_objects.append(env.Object(
+    Glob(join(test_a32_build_dir, '*.cc')),
+    CPPPATH = env['CPPPATH'] + [config.dir_tests]))
+
+test_a64_build_dir = PrepareVariantDir(join('test', 'a64'), TargetBuildDir(env))
+test_objects.append(env.Object(
+    Glob(join(test_a64_build_dir, '*.cc')),
+    CPPPATH = env['CPPPATH'] + [config.dir_tests]))
+
 # The test requires building the example files with specific options, so we
 # create a separate variant dir for the example objects built this way.
-test_examples_vdir = join(TargetBuildDir(env), 'test', 'test_examples')
-VariantDir(test_examples_vdir, '.')
-test_examples_obj = env.Object(
-    [Glob(join(test_examples_vdir, join('test', 'examples', '*.cc'))),
-             Glob(join(test_examples_vdir, join('examples', '*.cc')))],
+test_a64_examples_vdir = join(TargetBuildDir(env), 'test', 'a64', 'test_examples')
+VariantDir(test_a64_examples_vdir, '.')
+test_a64_examples_obj = env.Object(
+    [Glob(join(test_a64_examples_vdir, join('test', 'a64', 'examples/a64', '*.cc'))),
+     Glob(join(test_a64_examples_vdir, join('examples/a64', '*.cc')))],
     CCFLAGS = env['CCFLAGS'] + ['-DTEST_EXAMPLES'],
-    CPPPATH = env['CPPPATH'] + [config.dir_examples])
-test = env.Program(join(test_build_dir, 'test-runner'),
-                   [Glob(join(test_build_dir, '*.cc')), test_examples_obj],
-                   CPPPATH = env['CPPPATH'] + [config.dir_examples],
+    CPPPATH = env['CPPPATH'] + [config.dir_a64_examples] + [config.dir_tests])
+test_objects.append(test_a64_examples_obj)
+
+test = env.Program(join(test_build_dir, 'test-runner'), test_objects,
                    LIBS=[libvixl])
 env.Alias('tests', test)
 top_level_targets.Add('tests', 'Build the tests.')