Fix LLVM compilation issues

- Fix Clang -Wshorten-64-to-32 in mac_frame.cpp and cli_ping.cpp
- Move strict warning flags from global GN toolchain to private
  openthread_private_flags config on OT-owned targets only
- Use private configs for tcplp/mbedtls warning overrides
- Fix known mbedtls compilation error when -Wundef is set:
  Mbed-TLS/mbedtls#8950

Author: silabs-PiyushY

BUILD.gn

@@ -27,6 +27,20 @@
 
 import("etc/gn/openthread.gni")
 
+# Strict warnings for OpenThread sources only. Use private `configs =` on OT
+# targets, not `public_configs` on shared deps, so embedders (e.g. Matter with
+# Clang) keep their own warning defaults; a late -W* can undo flags such as
+# -Wno-unused-parameter on dependent translation units.
+config("openthread_private_flags") {
+  cflags = [
+    "-Werror",
+    "-Wall",
+    "-Wextra",
+    "-Wundef",
+    "-Wformat-nonliteral",
+  ]
+}
+
 config("openthread_config") {
   defines = []
   if (openthread_config_file != "") {

etc/gn/toolchain/BUILD.gn

@@ -26,21 +26,16 @@
 #
 
 toolchain("toolchain") {
-  diagnostic_cflags = [
-    "-Werror",
-    "-Wall",
-    "-Wextra",
-    "-Wundef",
-    "-Wformat-nonliteral",
-  ]
   if (use_clang) {
     cc = "clang"
     cxx = "clang++"
   } else {
     cc = "gcc"
     cxx = "g++"
   }
-  cflags = string_join(" ", diagnostic_cflags)
+  # Warning/diagnostic flags come from GN target configs ({{cflags}}), not from
+  # a global toolchain preset, so nothing is prepended here.
+  cflags = ""
 
   tool("cc") {
     depfile = "{{output}}.d"

examples/apps/cli/BUILD.gn

@@ -26,6 +26,7 @@
 #
 
 static_library("cli_uart") {
+  configs = [ "../../../:openthread_private_flags" ]
   sources = [ "cli_uart.cpp" ]
   include_dirs = [ "../../platforms" ]
   deps = [

examples/platforms/utils/mac_frame.cpp

@@ -413,7 +413,8 @@ otError otMacFrameProcessTxSfd(otRadioFrame *aFrame, uint64_t aRadioTime, otRadi
 #if OPENTHREAD_CONFIG_MAC_CSL_RECEIVER_ENABLE
     if (aRadioContext->mCslPresent) // CSL IE should be filled for every transmit attempt
     {
-        otMacFrameSetCslIe(aFrame, aRadioContext->mCslPeriod, ComputeCslPhase(aRadioTime, aRadioContext));
+        otMacFrameSetCslIe(aFrame, aRadioContext->mCslPeriod,
+                           ComputeCslPhase(static_cast<uint32_t>(aRadioTime), aRadioContext));
     }
 #endif
 #if OPENTHREAD_CONFIG_TIME_SYNC_ENABLE

src/cli/BUILD.gn

@@ -82,6 +82,7 @@ static_library("cli_config") {
 }
 
 static_library("libopenthread-cli-ftd") {
+  configs = [ "../..:openthread_private_flags" ]
   sources = openthread_cli_sources
   public_deps = [
     ":cli_config",
@@ -91,6 +92,7 @@ static_library("libopenthread-cli-ftd") {
 }
 
 static_library("libopenthread-cli-mtd") {
+  configs = [ "../..:openthread_private_flags" ]
   sources = openthread_cli_sources
   public_deps = [
     ":cli_config",

src/cli/cli_ping.cpp

@@ -233,8 +233,8 @@ void PingSender::HandlePingStatistics(const otPingSenderStatistics *aStatistics)
 
     if (aStatistics->mReceivedCount != 0)
     {
-        uint32_t avgRoundTripTime =
-            1000 * static_cast<uint64_t>(aStatistics->mTotalRoundTripTime) / aStatistics->mReceivedCount;
+        uint32_t avgRoundTripTime = static_cast<uint32_t>(
+            1000 * static_cast<uint64_t>(aStatistics->mTotalRoundTripTime) / aStatistics->mReceivedCount);
 
         OutputFormat(" Round-trip min/avg/max = %u/%u.%03u/%u ms.", aStatistics->mMinRoundTripTime,
                      static_cast<uint16_t>(avgRoundTripTime / 1000), static_cast<uint16_t>(avgRoundTripTime % 1000),

src/core/BUILD.gn

@@ -954,6 +954,7 @@ group("libopenthread_platform") {
 }
 
 static_library("libopenthread-ftd") {
+  configs = [ "../..:openthread_private_flags" ]
   sources = openthread_core_sources
   if (openthread_enable_core_config_args && openthread_config_tcp_enable) {
     deps = [ "../../third_party/tcplp" ]
@@ -963,6 +964,7 @@ static_library("libopenthread-ftd") {
 }
 
 static_library("libopenthread-mtd") {
+  configs = [ "../..:openthread_private_flags" ]
   sources = openthread_core_sources
   if (openthread_enable_core_config_args && openthread_config_tcp_enable) {
     deps = [ "../../third_party/tcplp" ]
@@ -972,6 +974,7 @@ static_library("libopenthread-mtd") {
 }
 
 static_library("libopenthread-radio") {
+  configs = [ "../..:openthread_private_flags" ]
   sources = openthread_radio_sources
   public_deps = [ ":libopenthread_platform" ]
   public_configs = [ "../..:openthread_radio_config" ]

src/lib/hdlc/BUILD.gn

@@ -26,6 +26,7 @@
 #
 
 static_library("libopenthread-hdlc") {
+  configs = [ "../../../:openthread_private_flags" ]
   sources = [
     "hdlc.cpp",
     "hdlc.hpp",

src/lib/platform/BUILD.gn

@@ -37,6 +37,7 @@ config("platform_config") {
 }
 
 static_library("libopenthread-platform") {
+  configs = [ "../../..:openthread_private_flags" ]
   sources = platform_sources
   public_deps = [ "../../core:libopenthread_core_headers" ]
   public_configs = [ ":platform_config" ]

src/lib/spinel/BUILD.gn

@@ -73,6 +73,7 @@ source_set("spinel-api") {
 }
 
 static_library("libopenthread-spinel-ncp") {
+  configs = [ "../../..:openthread_private_flags" ]
   sources = spinel_sources
   public_deps = [
     ":spinel-api",
@@ -86,6 +87,7 @@ static_library("libopenthread-spinel-ncp") {
 }
 
 static_library("libopenthread-radio-spinel") {
+  configs = [ "../../..:openthread_private_flags" ]
   sources = spinel_sources
   public_deps = [
     ":spinel-api",
@@ -105,6 +107,7 @@ static_library("libopenthread-radio-spinel") {
 }
 
 static_library("libopenthread-spinel-rcp") {
+  configs = [ "../../..:openthread_private_flags" ]
   sources = spinel_sources
   public_deps = [
     ":spinel-api",