Port arm, arm64, mipsle, and mips64le flags to GN

BUILD.gn

Index: BUILD.gn
diff --git a/BUILD.gn b/BUILD.gn
index 739d39d3286d00500ace774b3488515851fab3dd..2dbe08a12d9c61f8a81726bd588a74abf2867189 100644
--- a/BUILD.gn
+++ b/BUILD.gn
@@ -55,6 +55,12 @@ declare_args() {
   # describes various parameters of the VM for use by debuggers. See
   # tools/gen-postmortem-metadata.py for details.
   v8_postmortem_support = false
+
+  # Similar to vfp but on MIPS.
+  v8_can_use_fpu_instructions = true
+
+  # Similar to the ARM hard float ABI but on MIPS.
+  v8_use_mips_abi_hardfloat = true
 }
 
 v8_random_seed = "314159265"
@@ -168,48 +174,93 @@ config("toolchain") {
   defines = []
   cflags = []
 
-  # TODO(jochen): Add support for arm subarchs, mips, mipsel, mips64el.
-
   if (v8_target_arch == "arm") {
     defines += [ "V8_TARGET_ARCH_ARM" ]
-    if (current_cpu == "arm") {
-      if (arm_version == 7) {
-        defines += [ "CAN_USE_ARMV7_INSTRUCTIONS" ]
-      }
-      if (arm_fpu == "vfpv3-d16") {
-        defines += [ "CAN_USE_VFP3_INSTRUCTIONS" ]
-      } else if (arm_fpu == "vfpv3") {
-        defines += [
-          "CAN_USE_VFP3_INSTRUCTIONS",
-          "CAN_USE_VFP32DREGS",
-        ]
-      } else if (arm_fpu == "neon") {
-        defines += [
-          "CAN_USE_VFP3_INSTRUCTIONS",
-          "CAN_USE_VFP32DREGS",
-          "CAN_USE_NEON",
-        ]
-      }
-    } else {
-      # These defines ares used for the ARM simulator.
+    if (arm_version == 7) {
+      defines += [ "CAN_USE_ARMV7_INSTRUCTIONS" ]
+    }
+    if (arm_fpu == "vfpv3-d16") {
+      defines += [ "CAN_USE_VFP3_INSTRUCTIONS" ]
+    } else if (arm_fpu == "vfpv3") {
       defines += [
-        "CAN_USE_ARMV7_INSTRUCTIONS",
         "CAN_USE_VFP3_INSTRUCTIONS",
         "CAN_USE_VFP32DREGS",
-        "USE_EABI_HARDFLOAT=0",
+      ]
+    } else if (arm_fpu == "neon") {
+      defines += [
+        "CAN_USE_VFP3_INSTRUCTIONS",
+        "CAN_USE_VFP32DREGS",
+        "CAN_USE_NEON",
       ]
     }
-
     # TODO(jochen): Add support for arm_test_noprobe.
+
+    if (current_cpu != "arm") {
+      # These defines ares used for the ARM simulator.
+      if (arm_float_abi == "hard") {
+        defines += [ "USE_EABI_HARDFLOAT=1" ]
+      } else if (arm_float_abi == "softfp") {
+        defines += [ "USE_EABI_HARDFLOAT=0" ]
+      }
+    }
   }
   if (v8_target_arch == "arm64") {
     defines += [ "V8_TARGET_ARCH_ARM64" ]
   }
+  # TODO(jochen): Add support for mips.
   if (v8_target_arch == "mipsel") {
     defines += [ "V8_TARGET_ARCH_MIPS" ]
+    if (v8_can_use_fpu_instructions) {
+      defines += [ "CAN_USE_FPU_INSTRUCTIONS" ]
+    }
+    if (v8_use_mips_abi_hardfloat) {
+      defines += [
+        "__mips_hard_float=1",
+        "CAN_USE_FPU_INSTRUCTIONS",
+      ]
+    } else {
+      defines += [ "__mips_soft_float=1" ]
+    }
+    if (mips_arch_variant == "r6") {
+      defines += [
+        "_MIPS_ARCH_MIPS32R6",
+        "FPU_MODE_FP64",
+      ]
+    } else if (mips_arch_variant == "r2") {
+      defines += [ "_MIPS_ARCH_MIPS32R2" ]
+      if (mips_fpu_mode == "fp64") {
+        defines += [ "FPU_MODE_FP64" ]
+      } else if (mips_fpu_mode == "fpxx") {
+        defines += [ "FPU_MODE_FPXX" ]
+      } else if (mips_fpu_mode == "fp32") {
+        defines += [ "FPU_MODE_FP32" ]
+      }
+    } else if (mips_arch_variant == "r1") {
+      defines += [ "FPU_MODE_FP32" ]
+    }
+    # TODO(jochen): Add support for mips_arch_variant rx and loongson.
   }
+  # TODO(jochen): Add support for mips64.
   if (v8_target_arch == "mips64el") {
     defines += [ "V8_TARGET_ARCH_MIPS64" ]
+    if (v8_can_use_fpu_instructions) {
+      defines += [ "CAN_USE_FPU_INSTRUCTIONS" ]
+    }
+    # TODO(jochen): Add support for big endian host byteorder.
+    defines += [ "V8_TARGET_ARCH_MIPS64_LE" ]
+    if (v8_use_mips_abi_hardfloat) {
+      defines += [
+        "__mips_hard_float=1",
+        "CAN_USE_FPU_INSTRUCTIONS",
+      ]
+    } else {
+      defines += [ "__mips_soft_float=1" ]
+    }
+    if (mips_arch_variant == "r6") {
+      defines += [ "_MIPS_ARCH_MIPS64R6" ]
+    } else if (mips_arch_variant == "r2") {
+      defines += [ "_MIPS_ARCH_MIPS64R2" ]
+    }
   }
   if (v8_target_arch == "s390") {
     defines += [ "V8_TARGET_ARCH_S390" ]