Add compiler and linker flags for MIPS.

build/config/compiler/BUILD.gn

Index: build/config/compiler/BUILD.gn
diff --git a/build/config/compiler/BUILD.gn b/build/config/compiler/BUILD.gn
index dcd5d6596d619d40e2389f20f7fee94cdd351694..c0a835fe805882032064df9a7a432a5df505f892 100644
--- a/build/config/compiler/BUILD.gn
+++ b/build/config/compiler/BUILD.gn
@@ -12,6 +12,19 @@ if (is_posix) {
 
 import("//build/toolchain/ccache.gni")
 
+# Default arch variants for MIPS platforms.
+if (cpu_arch == "mipsel") {
+  mips_arch_variant_default = "r1"
+} else if (cpu_arch == "mips64el") {
+  if (is_android) {
+    mips_arch_variant_default = "r6"
+  } else {
+    mips_arch_variant_default = "r2"
+  }
+} else {
+  mips_arch_variant_default = ""
+}
+
 declare_args() {
   # Normally, Android builds are lightly optimized, even for debug builds, to
   # keep binary size down. Setting this flag to true disables such optimization
@@ -23,6 +36,9 @@ declare_args() {
   # you are using a custom toolchain and need to control -B in cflags.
   linux_use_bundled_binutils = is_linux && cpu_arch == "x64"
 
+  # MIPS arch variant.
+  mips_arch_variant = mips_arch_variant_default

[wtc, 2015/01/07 23:00:22]

Is there a better way to provide a platform-dependent default value for a gn
buildvariable?

+
   # Compile in such a way as to enable profiling of the generated code. For
   # example, don't omit the frame pointer and leave in symbols.
   enable_profiling = false
@@ -271,6 +287,51 @@ config("compiler") {
           ]
         }
       }
+    } else if (cpu_arch == "mipsel") {
+      # Don't set the compiler flags for the WebView build. These will come
+      # from the Android build system.
+      if (!is_android_webview_build) {
+        if (mips_arch_variant == "r6") {
+          cflags += [
+            "-mips32r6",
+            "-Wa,-mips32r6",
+          ]
+          if (is_android) {
+            ldflags += [
+              "-mips32r6",
+              "-Wl,-melf32ltsmip",

[wtc, 2015/01/07 23:00:22]

I don't know what this flag is for. I copied it from build/common.gypi.

+            ]
+          }
+        } else if (mips_arch_variant == "r2") {
+          cflags += [
+            "-mips32r2",
+            "-Wa,-mips32r2",
+          ]
+        } else if (mips_arch_variant == "r1") {
+          cflags += [
+            "-mips32",
+            "-Wa,-mips32",
+          ]
+        }
+      }
+    } else if (cpu_arch == "mips64el") {
+      # Don't set the compiler flags for the WebView build. These will come
+      # from the Android build system.
+      if (!is_android_webview_build) {
+        if (mips_arch_variant == "r6") {
+          cflags += [
+            "-mips64r6",
+            "-Wa,-mips64r6",
+          ]
+          ldflags += [ "-mips64r6" ]
+        } else if (mips_arch_variant == "r2") {
+          cflags += [
+            "-mips64r2",
+            "-Wa,-mips64r2",
+          ]
+          ldflags += [ "-mips64r2" ]
+        }
+      }
     }
 
     defines += [ "_FILE_OFFSET_BITS=64" ]