Adjust pnacl-translate sbtc flag override mechanism to append.

pnacl/driver/pnacl-translate.py

Index: pnacl/driver/pnacl-translate.py
diff --git a/pnacl/driver/pnacl-translate.py b/pnacl/driver/pnacl-translate.py
index abd43103d27c53af50f2ab154b4d01d52394483f..23e4d5b827bece6631ff5f18cf7ec05c4388b8da 100755
--- a/pnacl/driver/pnacl-translate.py
+++ b/pnacl/driver/pnacl-translate.py
@@ -125,42 +125,29 @@ EXTRA_ENV = {
 
   # LLC flags which set the target and output type.
   # These are handled separately by libLTO.

[Derek Schuff, 2013/03/06 21:10:12]

this line of the comment still relevant?

[jvoung (off chromium), 2013/03/06 21:26:58]

Probably not (the libLTO part?).  It sounds like libLTO is referring to
LTOModule.cpp, which is used during bitcode linking.  That really only reads the
triple mentioned in the bitcode file itself (or a default if no triple string
exists in the bitcode file), so we never set the commandline for libLTO.

Removed.

-  'LLC_FLAGS_TARGET' : '-mcpu=${LLC_MCPU} ' +
-                       '-mtriple=${TRIPLE} ' +
+  'LLC_FLAGS_TARGET' : '-mtriple=${TRIPLE} ' +
                        '-filetype=${filetype}',
   # Append additional non-default flags here.
-  'LLC_FLAGS_EXTRA' : '${#OPT_LEVEL ? -O${OPT_LEVEL}} ' +
+  'LLC_FLAGS_EXTRA' : '${FAST_TRANSLATION ? ${LLC_FLAGS_FAST}} ' +
+                      '${#OPT_LEVEL ? -O${OPT_LEVEL}} ' +
                       '${OPT_LEVEL == 0 ? -disable-fp-elim}',
 
   # Opt level from command line (if any)
   'OPT_LEVEL' : '',
 
-  # slower translation == faster code
-  'LLC_FLAGS_SLOW':
-  # Due to a quadratic algorithm used for tail merging
-  # capping it at 50 helps speed up translation
-                     '-tail-merge-threshold=50',
-
   # faster translation == slower code
   'LLC_FLAGS_FAST' : '${LLC_FLAGS_FAST_%ARCH%}',
 
-  'LLC_FLAGS_FAST_X8632':
-                          '-O0 ' +
-  # This, surprisingly, makes a measurable difference
+  'LLC_FLAGS_FAST_X8632': '-O0 ' +
+                          # This, surprisingly, makes a measurable difference
                           '-tail-merge-threshold=20',
-  'LLC_FLAGS_FAST_X8664':
-                          '-O0 ' +
+  'LLC_FLAGS_FAST_X8664': '-O0 ' +
                           '-tail-merge-threshold=20',
-  'LLC_FLAGS_FAST_ARM':
-  # due to slow turn around times ARM settings have not been explored in depth
-                          '-O0 ' +
+  'LLC_FLAGS_FAST_ARM':   '-O0 ' +
                           '-tail-merge-threshold=20',
   'LLC_FLAGS_FAST_MIPS32': '-fast-isel -tail-merge-threshold=20',
 
-  'LLC_FLAGS': '${LLC_FLAGS_TARGET} ' +
-               '${LLC_FLAGS_COMMON} ' +
-               '${LLC_FLAGS_%ARCH%} ' +
-               '${FAST_TRANSLATION ? ${LLC_FLAGS_FAST} : ${LLC_FLAGS_SLOW}} ' +
+  'LLC_FLAGS': '${LLC_FLAGS_TARGET} ${LLC_FLAGS_COMMON} ${LLC_FLAGS_%ARCH%} ' +
                '${LLC_FLAGS_EXTRA}',
 
   # CPU that is representative of baseline feature requirements for NaCl
@@ -169,14 +156,15 @@ EXTRA_ENV = {
   # Note: this may be different from the in-browser translator, which may
   # do auto feature detection based on CPUID, but constrained by what is
   # accepted by NaCl validators.
-  'LLC_MCPU'        : '${LLC_MCPU_%ARCH%}',
+  'LLC_MCPU'        : '-mcpu=${LLC_MCPU_%ARCH%}',
   'LLC_MCPU_ARM'    : 'cortex-a8',
   'LLC_MCPU_X8632'  : 'pentium4',
   'LLC_MCPU_X8664'  : 'core2',
   'LLC_MCPU_MIPS32' : 'mips32r2',
 
   # Note: this is only used in the unsandboxed case
-  'RUN_LLC'       : '${LLVM_LLC} ${LLC_FLAGS} ${input} -o ${output} ' +
+  'RUN_LLC'       : '${LLVM_LLC} ${LLC_FLAGS} ${LLC_MCPU} '
+                    '${input} -o ${output} ' +
                     '-metadata-text ${output}.meta',
   # Rate in bits/sec to stream the bitcode from sel_universal over SRPC
   # for testing. Defaults to 1Gbps (effectively unlimited).
@@ -199,7 +187,8 @@ TranslatorPatterns = [
   ( '(-ffunction-sections)', "env.append('LLC_FLAGS_EXTRA', $0)"),
   ( '(--gc-sections)',       "env.append('LD_FLAGS', $0)"),
   ( '(-mattr=.*)', "env.append('LLC_FLAGS_EXTRA', $0)"),
-  ( '-mcpu=(.*)', "env.set('LLC_MCPU', $0)"),
+  ( '(-mcpu=.*)', "env.set('LLC_MCPU', '')\n"
+                  "env.append('LLC_FLAGS_EXTRA', $0)"),
   # Allow overriding the -O level.
   ( '-O([0-3])', "env.set('OPT_LEVEL', $0)"),
 
@@ -465,9 +454,6 @@ def ToggleDefaultCommandlineLD(inputs, infile):
 
 
 def RequiresNonStandardLLCCommandline():
-  if env.getbool('FAST_TRANSLATION'):
-    return ('FAST_TRANSLATION', True)
-
   extra_flags = env.get('LLC_FLAGS_EXTRA')
   if extra_flags != []:
     reason = 'Has additional llc flags: %s' % extra_flags
@@ -523,10 +509,9 @@ def RunLLCSandboxed():
   driver_tools.CheckTranslatorPrerequisites()
   infile = env.getone('input')
   outfile = env.getone('output')
-  flags = env.get('LLC_FLAGS')
   if not driver_tools.IsBitcode(infile):
     Log.Fatal('Input to sandboxed translator must be bitcode')
-  script = MakeSelUniversalScriptForLLC(infile, outfile, flags)
+  script = MakeSelUniversalScriptForLLC(infile, outfile)
   command = ('${SEL_UNIVERSAL_PREFIX} ${SEL_UNIVERSAL} ${SEL_UNIVERSAL_FLAGS} '
     '-- ${LLC_SB}')
   _, stdout, _  = driver_tools.Run(command,
@@ -544,14 +529,19 @@ def RunLLCSandboxed():
   needed_libs = [ lib for lib in needed_str.split(r'\n') if lib]
   return is_shared, soname, needed_libs
 
-def BuildLLCCommandLine(flags):
+def BuildOverrideLLCCommandLine():
+  extra_flags = env.get('LLC_FLAGS_EXTRA')
+  # The mcpu is not part of the default flags, so append that too.
+  mcpu = env.getone('LLC_MCPU')
+  if mcpu:
+    extra_flags.append(mcpu)
   # command_line is a NUL (\x00) terminated sequence.
   kTerminator = '\0'
-  command_line = kTerminator.join(['llc'] + flags) + kTerminator
+  command_line = kTerminator.join(extra_flags) + kTerminator
   command_line_escaped = command_line.replace(kTerminator, '\\x00')
   return len(command_line), command_line_escaped
 
-def MakeSelUniversalScriptForLLC(infile, outfile, flags):
+def MakeSelUniversalScriptForLLC(infile, outfile):
   script = []
   script.append('readwrite_file objfile %s' % outfile)
   stream_rate = int(env.getraw('BITCODE_STREAM_RATE'))
@@ -559,8 +549,8 @@ def MakeSelUniversalScriptForLLC(infile, outfile, flags):
   if UseDefaultCommandlineLLC():
     script.append('rpc StreamInit h(objfile) * s()')
   else:
-    cmdline_len, cmdline_escaped = BuildLLCCommandLine(flags)
-    script.append('rpc StreamInitWithCommandLine h(objfile) C(%d,%s) * s()' %
+    cmdline_len, cmdline_escaped = BuildOverrideLLCCommandLine()
+    script.append('rpc StreamInitWithOverrides h(objfile) C(%d,%s) * s()' %
                   (cmdline_len, cmdline_escaped))
   # specify filename, chunk size and rate in bits/s
   script.append('stream_file %s %s %s' % (infile, 64 * 1024, stream_rate))