[libyuv] Simplify RVV configuration in BUILD.bazel and libyuv.bzl

Restructure RISC-V Vector (RVV) configuration to follow the pattern
used by NEON and SVE:
- Move RVV_COPTS immediately after SVE_COPTS.
- Define ENABLE_RVV_COPTS (-march=rv32gcv) and ENABLE_RVV64_COPTS
  (-march=rv64gcv) with SUPPORTS_RVV_COPTS (-DLIBYUV_RVV).
- Revert ALL_COPTS to PLATFORM_COPTS so RVV vector flags are not
  applied to generic sources.
- Add ALL_RVV_COPTS, RVV_DEPS, and libyuv_rvv_impl target.
- Update libyuv.bzl to add libyuv_rvv_srcs and exclude source/*rvv*.cc
  from libyuv_srcs.

R=wtc@google.com

Test: cmake -B out/Release -DUNIT_TEST=ON && cmake --build out/Release
Bug: none
Change-Id: Ia60a8bc1da9db46f0c5295064d7b9d3d5609a38f
TAG=agy
CONV=06856819-10a7-4815-93d3-cdcd32da7495
Reviewed-on: https://chromium-review.googlesource.com/c/libyuv/libyuv/+/8357976
Reviewed-by: richard winterton <rrwinterton@gmail.com>

BUILD.bazel

@@ -5,7 +5,7 @@
 #   and scaling.
 
 load("@bazel_skylib//lib:selects.bzl", "selects")
-load(":libyuv.bzl", "libyuv_hdrs", "libyuv_neon_srcs", "libyuv_srcs", "libyuv_sve_srcs", "libyuv_test_srcs")
+load(":libyuv.bzl", "libyuv_hdrs", "libyuv_neon_srcs", "libyuv_rvv_srcs", "libyuv_srcs", "libyuv_sve_srcs", "libyuv_test_srcs")
 
 # Detect if we are in Google's internal repository (where source files are
 # under files/) or open source (where source files are at the root).
@@ -44,6 +44,24 @@ SVE_COPTS = select({
     "//conditions:default": [],
 })
 
+SUPPORTS_RVV_COPTS = [
+    "-DLIBYUV_RVV",
+]
+
+ENABLE_RVV_COPTS = [
+    "-march=rv32gcv",
+]
+
+ENABLE_RVV64_COPTS = [
+    "-march=rv64gcv",
+]
+
+RVV_COPTS = select({
+    "@platforms//cpu:riscv32": ENABLE_RVV_COPTS + SUPPORTS_RVV_COPTS,
+    "@platforms//cpu:riscv64": ENABLE_RVV64_COPTS + SUPPORTS_RVV_COPTS,
+    "//conditions:default": [],
+})
+
 PLATFORM_COPTS = select({
     "@platforms//os:android": ["-DHAVE_JPEG"],
     "@platforms//os:linux": ["-DHAVE_JPEG"],
@@ -56,26 +74,14 @@ PLATFORM_COPTS = select({
     "-DGOOGLE_COMMANDLINEFLAGS_FULL_API",
 ]
 
-RVV_COPTS = select({
+ALL_COPTS = PLATFORM_COPTS
-    "@platforms//cpu:riscv64": [
-        "-march=rv64gcv",
-        "-fno-vectorize",
-        "-fno-slp-vectorize",
-    ],
-    "@platforms//cpu:riscv32": [
-        "-march=rv32gcv",
-        "-fno-vectorize",
-        "-fno-slp-vectorize",
-    ],
-    "//conditions:default": [],
-})
-
-ALL_COPTS = PLATFORM_COPTS + RVV_COPTS
 
 ALL_NEON_COPTS = NEON_COPTS + PLATFORM_COPTS
 
 ALL_SVE_COPTS = SVE_COPTS + PLATFORM_COPTS
 
+ALL_RVV_COPTS = RVV_COPTS + PLATFORM_COPTS
+
 NEON_DEPS = select({
     "@platforms//cpu:armv7": [":libyuv_neon_impl"],
     "@platforms//cpu:aarch64": [":libyuv_neon_impl"],
@@ -87,6 +93,12 @@ SVE_DEPS = select({
     "//conditions:default": [],
 })
 
+RVV_DEPS = select({
+    "@platforms//cpu:riscv32": [":libyuv_rvv_impl"],
+    "@platforms//cpu:riscv64": [":libyuv_rvv_impl"],
+    "//conditions:default": [],
+})
+
 PLATFORM_DEPS = select({
     "@platforms//os:android": ["@libjpeg_turbo//:jpeg"],
     "@platforms//os:linux": ["@libjpeg_turbo//:jpeg"],
@@ -95,7 +107,7 @@ PLATFORM_DEPS = select({
     "//conditions:default": [],
 })
 
-ALL_DEPS = NEON_DEPS + SVE_DEPS + PLATFORM_DEPS
+ALL_DEPS = NEON_DEPS + SVE_DEPS + RVV_DEPS + PLATFORM_DEPS
 
 cc_library(
     name = "libyuv",
@@ -174,6 +186,15 @@ cc_library(
     alwayslink = 1,
 )
 
+cc_library(
+    name = "libyuv_rvv_impl",
+    srcs = libyuv_rvv_srcs(PREFIX),
+    copts = ALL_RVV_COPTS,
+    includes = [PREFIX + "include"],
+    visibility = ["//visibility:private"],
+    alwayslink = 1,
+)
+
 cc_test(
     name = "libyuv_test",
     srcs = libyuv_test_srcs(PREFIX),

libyuv.bzl

@@ -10,6 +10,7 @@ def libyuv_srcs(prefix = ""):
         ],
         exclude = [
             prefix + "source/*neon*.cc",
+            prefix + "source/*rvv*.cc",
             prefix + "source/*sve*.cc",
             prefix + "source/*sme*.cc",
         ],
@@ -30,6 +31,12 @@ def libyuv_neon_srcs(prefix = ""):
         prefix + "include/libyuv/*.h",
     ])
 
+def libyuv_rvv_srcs(prefix = ""):
+    return native.glob([
+        prefix + "source/*rvv*.cc",
+        prefix + "include/libyuv/*.h",
+    ])
+
 def libyuv_sve_srcs(prefix = ""):
     return native.glob([
         prefix + "source/*sve*.cc",