Add the mips_dsp_rev build variable.

build/common.gypi

Index: build/common.gypi
diff --git a/build/common.gypi b/build/common.gypi
index 1266286fb21062ccd14655de31415bc48665017f..190d80531457b44649b032918f28d77a8feb73c1 100644
--- a/build/common.gypi
+++ b/build/common.gypi
@@ -184,6 +184,13 @@
         # below for MIPS targets.
         'mips_arch_variant%': '',
 
+        # MIPS DSP ASE revision. Possible values are:
+        #   0: unavailable
+        #   1: revision 1
+        #   2: revision 2
+        # Default: 0.
+        'mips_dsp_rev%': 0,
+
         'conditions': [
           # Ash needs Aura.
           ['use_aura==0', {
@@ -276,6 +283,7 @@
       'target_arch%': '<(target_arch)',
       'target_subarch%': '<(target_subarch)',
       'mips_arch_variant%': '<(mips_arch_variant)',
+      'mips_dsp_rev%': '<(mips_dsp_rev)',
       'toolkit_views%': '<(toolkit_views)',
       'desktop_linux%': '<(desktop_linux)',
       'use_aura%': '<(use_aura)',
@@ -1062,6 +1070,7 @@
     'target_arch%': '<(target_arch)',
     'target_subarch%': '<(target_subarch)',
     'mips_arch_variant%': '<(mips_arch_variant)',
+    'mips_dsp_rev%': '<(mips_dsp_rev)',
     'host_arch%': '<(host_arch)',
     'toolkit_views%': '<(toolkit_views)',
     'ui_compositor_image_transport%': '<(ui_compositor_image_transport)',
@@ -2281,6 +2290,9 @@
       ['target_arch=="mipsel" and mips_arch_variant=="r2" and android_webview_build==0', {
         'mips_fpu_mode%': 'fp32',
       }],
+      ['target_arch=="mipsel" and mips_arch_variant!="r6" and android_webview_build==0', {
+        'mips_float_abi%': 'hard',

[wtc, 2015/02/20 01:58:56]

The conditional expression and the default value match the code for 'mips_fpu'
in third_party/webrtc/build/common.gypi.

+      }],
 
       ['android_webview_build==1', {
         # The WebView build gets its cpu-specific flags from the Android build system.
@@ -2290,6 +2302,7 @@
         'arm_float_abi%': '',
         'arm_thumb%': 0,
         'mips_fpu_mode%': '',
+        'mips_float_abi%': '',
       }],
 
       # Enable brlapi by default for chromeos.
@@ -4038,11 +4051,31 @@
                     ],
                   }],
                   ['android_webview_build==0 and mips_arch_variant=="r2"', {
+                    'conditions': [
+                      ['mips_fpu_mode=="fp32"', {
+                        'cflags': ['-mfp32'],

[kjellander_chromium, 2015/02/23 13:22:35]

at
https://code.google.com/p/webrtc/source/browse/trunk/webrtc/build/common.gypi...
the -mips32r2 flag is added to cflags+cflags_cc for this case. 
Shouldn't they be here too, or does -mfp32 have the same effect?

[brettw, 2015/02/23 18:51:36]

cflags in GN and GYP apply to both C and C++ files. cflags_c and cflags_cc are
applied on top of those to the corresponding specific types.

So maybe the handling of -mips32r2 is wrong.

[wtc, 2015/02/23 20:15:51]

Brett, thank you for answering Henrik's question. webrtc/build/common.gypi
incorrectly adds the same compiler flag to both cflags and cflags_cc. I verified
that when compiling C++ files, that flag appears twice on the compiler command
line.

Henrik, this also answers your questions about the -mdsp and -mdspr2 below.

+                      }],
+                      ['mips_fpu_mode=="fp64"', {
+                        'cflags': ['-mfp64'],
+                      }],
+                      ['mips_fpu_mode=="fpxx"', {
+                        'cflags': ['-mfpxx'],
+                      }],
+                    ],

[wtc, 2015/02/20 01:58:56]

This block of code matches the code for 'mips_fpu_mode' in
v8/build/toolchain.gypi.

                     'cflags': ['-mips32r2', '-Wa,-mips32r2'],
                   }],
                   ['android_webview_build==0 and mips_arch_variant=="r1"', {
                     'cflags': ['-mips32', '-Wa,-mips32'],
                   }],
+                  ['android_webview_build==0 and mips_dsp_rev==1', {
+                    'cflags': ['-mdsp'],

[kjellander_chromium, 2015/02/23 13:22:35]

https://code.google.com/p/webrtc/source/browse/trunk/webrtc/build/common.gypi...
also adds this to cflags_cc. Is that redundant?

+                  }],
+                  ['android_webview_build==0 and mips_dsp_rev==2', {
+                    'cflags': ['-mdspr2'],

[kjellander_chromium, 2015/02/23 13:22:35]

https://code.google.com/p/webrtc/source/browse/trunk/webrtc/build/common.gypi...
also adds this to cflags_cc. Is that redundant?

+                  }],

[wtc, 2015/02/20 01:58:56]

This block of code matches the code for mips_dsp_rev in
third_party/webrtc/build/common.gypi.

+                  ['android_webview_build==0 and mips_arch_variant!="r6"', {
+                    'cflags': ['-m<(mips_float_abi)-float'],
+                  }],

[wtc, 2015/02/20 01:58:56]

This block of code matches the code for mips_fpu in
third_party/webrtc/build/common.gypi.

                 ],
                 'ldflags': [
                   '-Wl,--no-keep-memory'