build: fix clang-cl builds, add CI job

- appveyor: add build-only job for clang-cl.

- cmake: `-pedantic-errors` enables `-Werror,-Wlanguage-extension-token`
  automatically, which makes `__int64` detection fail.
  Explictly disable this compiler warning for clang-cl to make the
  feature detection work and to accept `__int64` in the source code.

- cmake: disable `-Wlanguage-extension-token` warning for clang-cl
  to fix these when encountering `__int64`:
  ```
  lib/formdata.c(797,29): error : extension used [-Werror,-Wlanguage-extension-token]
  lib/warnless.c(117,33): error : extension used [-Werror,-Wlanguage-extension-token]
  lib/warnless.c(60,28): message : expanded from macro 'CURL_MASK_SCOFFT'
  lib/warnless.c(59,38): message : expanded from macro 'CURL_MASK_UCOFFT'
  include\curl/system.h(352,40): message : expanded from macro 'CURL_TYPEOF_CURL_OFF_T'
  ```

- make `__GNUC__` warning suppressions apply to `__clang__` too.
  Necessary for clang-cl, which defines the latter, but not the former.
  (Regular clang defines both.)

- examples: fix clang-cl compiler warning in `http2-upload.c`.
  ```
  docs\examples\http2-upload.c(56,5): error : no previous prototype for function 'my_gettimeofday' [-Werror,-Wmissing-prototypes]
  docs\examples\http2-upload.c(56,1): message : declare 'static' if the function is not intended to be used outside of this translation unit
  ```

- unit2604: add missing `#pragma GCC diagnostic pop`.
  Follow-up to e53523fef0 #14859

- unit1652: limit compiler warning suppression to GCC.
  They do not affect clang builds.
  Follow-up to 71cf0d1fca #14772

Closes #15449

CMake/PickyWarnings.cmake

@@ -31,6 +31,9 @@ if(CURL_WERROR AND
      NOT CMAKE_VERSION VERSION_LESS 3.23.0) OR  # to avoid check_symbol_exists() conflicting with GCC -pedantic-errors
    CMAKE_C_COMPILER_ID MATCHES "Clang"))
   list(APPEND _picky "-pedantic-errors")
+  if(MSVC)  # clang-cl
+    list(APPEND _picky "-Wno-language-extension-token")  # Override default error to make __int64 size detection pass
+  endif()
 endif()
 
 if(APPLE AND
@@ -130,9 +133,13 @@ if(PICKY_COMPILER)
         ${_picky_common_old}
         -Wshift-sign-overflow              # clang  2.9
         -Wshorten-64-to-32                 # clang  1.0
-        -Wlanguage-extension-token         # clang  3.0
         -Wformat=2                         # clang  3.0  gcc  4.8
       )
+      if(NOT MSVC)
+        list(APPEND _picky_enable
+          -Wlanguage-extension-token         # clang  3.0  # Avoid for clang-cl to allow __int64
+        )
+      endif()
       # Enable based on compiler version
       if((CMAKE_C_COMPILER_ID STREQUAL "Clang"      AND NOT CMAKE_C_COMPILER_VERSION VERSION_LESS 3.6) OR
          (CMAKE_C_COMPILER_ID STREQUAL "AppleClang" AND NOT CMAKE_C_COMPILER_VERSION VERSION_LESS 6.3))

appveyor.sh

@@ -38,6 +38,7 @@ openssl_root="$(cygpath "${openssl_root_win}")"
 if [ "${BUILD_SYSTEM}" = 'CMake' ]; then
   options=''
   [[ "${TARGET:-}" = *'ARM64'* ]] && SKIP_RUN='ARM64 architecture'
+  [ -n "${TOOLSET:-}" ] && options+=" -T ${TOOLSET}"
   [ "${OPENSSL}" = 'ON' ] && options+=" -DOPENSSL_ROOT_DIR=${openssl_root_win}"
   [ -n "${CURLDEBUG:-}" ] && options+=" -DENABLE_CURLDEBUG=${CURLDEBUG}"
   [ "${PRJ_CFG}" = 'Debug' ] && options+=' -DCMAKE_RUNTIME_OUTPUT_DIRECTORY_DEBUG='
@@ -62,6 +63,9 @@ if [ "${BUILD_SYSTEM}" = 'CMake' ]; then
     '-DCMAKE_INSTALL_PREFIX=C:/curl' \
     "-DCMAKE_BUILD_TYPE=${PRJ_CFG}" \
     '-DCURL_USE_LIBPSL=OFF'
+  if false; then
+    cat _bld/CMakeFiles/CMakeConfigureLog.yaml 2>/dev/null || true
+  fi
   echo 'curl_config.h'; grep -F '#define' _bld/lib/curl_config.h | sort || true
   # shellcheck disable=SC2086
   if ! cmake --build _bld --config "${PRJ_CFG}" --parallel 2 -- ${BUILD_OPT:-}; then
@@ -119,10 +123,6 @@ else
   echo "Skip running curl.exe. Reason: ${SKIP_RUN}"
 fi
 
-if false; then
-  cat CMakeFiles/CMakeConfigureLog.yaml 2>/dev/null || true
-fi
-
 # build tests
 
 if [[ "${TFLAGS}" != 'skipall' ]] && \

appveyor.yml

@@ -89,6 +89,16 @@ environment:
       SCHANNEL: 'ON'
       ENABLE_UNICODE: 'OFF'
       EXAMPLES: 'ON'
+    - job_name: 'CMake, VS2022, Debug, x64, Schannel, Static, Unicode, Build-tests & examples, clang-cl'
+      APPVEYOR_BUILD_WORKER_IMAGE: 'Visual Studio 2022'
+      BUILD_SYSTEM: CMake
+      PRJ_GEN: 'Visual Studio 17 2022'
+      TARGET: '-A x64'
+      PRJ_CFG: Debug
+      SCHANNEL: 'ON'
+      ENABLE_UNICODE: 'ON'
+      EXAMPLES: 'ON'
+      TOOLSET: 'ClangCl'
     - job_name: 'CMake, VS2022, Debug, x64, Schannel, Static, Unicode, Build-tests'
       APPVEYOR_BUILD_WORKER_IMAGE: 'Visual Studio 2022'
       BUILD_SYSTEM: CMake

docs/examples/http2-upload.c

@@ -53,6 +53,7 @@
 
 #ifdef _MSC_VER
 #define gettimeofday(a, b) my_gettimeofday((a), (b))
+static
 int my_gettimeofday(struct timeval *tp, void *tzp)
 {
   (void)tzp;

lib/content_encoding.c

@@ -33,13 +33,13 @@
 #endif
 
 #ifdef HAVE_BROTLI
-#if defined(__GNUC__)
+#if defined(__GNUC__) || defined(__clang__)
 /* Ignore -Wvla warnings in brotli headers */
 #pragma GCC diagnostic push
 #pragma GCC diagnostic ignored "-Wvla"
 #endif
 #include <brotli/decode.h>
-#if defined(__GNUC__)
+#if defined(__GNUC__) || defined(__clang__)
 #pragma GCC diagnostic pop
 #endif
 #endif

lib/curl_setup.h

@@ -33,7 +33,7 @@
 
 /* FIXME: Delete this once the warnings have been fixed. */
 #if !defined(CURL_WARN_SIGN_CONVERSION)
-#ifdef __GNUC__
+#if defined(__GNUC__) || defined(__clang__)
 #pragma GCC diagnostic ignored "-Wsign-conversion"
 #endif
 #endif

lib/version.c

@@ -63,13 +63,13 @@
 #endif
 
 #ifdef HAVE_BROTLI
-#if defined(__GNUC__)
+#if defined(__GNUC__) || defined(__clang__)
 /* Ignore -Wvla warnings in brotli headers */
 #pragma GCC diagnostic push
 #pragma GCC diagnostic ignored "-Wvla"
 #endif
 #include <brotli/decode.h>
-#if defined(__GNUC__)
+#if defined(__GNUC__) || defined(__clang__)
 #pragma GCC diagnostic pop
 #endif
 #endif

src/tool_main.c

@@ -216,7 +216,7 @@ static void main_free(struct GlobalConfig *config)
 ** curl tool main function.
 */
 #ifdef _UNICODE
-#if defined(__GNUC__)
+#if defined(__GNUC__) || defined(__clang__)
 /* GCC does not know about wmain() */
 #pragma GCC diagnostic push
 #pragma GCC diagnostic ignored "-Wmissing-prototypes"
@@ -287,7 +287,7 @@ int main(int argc, char *argv[])
 }
 
 #ifdef _UNICODE
-#ifdef __GNUC__
+#if defined(__GNUC__) || defined(__clang__)
 #pragma GCC diagnostic pop
 #endif
 #endif

tests/libtest/lib557.c

@@ -37,7 +37,7 @@
 
 #include "memdebug.h"
 
-#ifdef __GNUC__
+#if defined(__GNUC__) || defined(__clang__)
 #pragma GCC diagnostic push
 #pragma GCC diagnostic ignored "-Wformat"
 #pragma GCC diagnostic ignored "-Wformat-extra-args"
@@ -1559,6 +1559,6 @@ CURLcode test(char *URL)
     return CURLE_OK;
 }
 
-#ifdef __GNUC__
+#if defined(__GNUC__) || defined(__clang__)
 #pragma GCC diagnostic pop
 #endif

tests/unit/unit1398.c

@@ -23,7 +23,7 @@
  ***************************************************************************/
 #include "curlcheck.h"
 
-#ifdef __GNUC__
+#if defined(__GNUC__) || defined(__clang__)
 #pragma GCC diagnostic push
 #pragma GCC diagnostic ignored "-Wformat"
 #endif
@@ -186,6 +186,6 @@ fail_unless(rc == 128, "return code should be 128");
 
 UNITTEST_STOP
 
-#ifdef __GNUC__
+#if defined(__GNUC__) || defined(__clang__)
 #pragma GCC diagnostic pop
 #endif

tests/unit/unit1652.c

@@ -26,15 +26,6 @@
 #include "urldata.h"
 #include "sendf.h"
 
-#ifdef __GNUC__
-#pragma GCC diagnostic push
-#pragma GCC diagnostic ignored "-Wformat"
-#pragma GCC diagnostic ignored "-Wformat-zero-length"
-#if !defined(__clang__) && __GNUC__ >= 7
-#pragma GCC diagnostic ignored "-Wformat-overflow"
-#endif
-#endif
-
 /*
  * This test hardcodes the knowledge of the buffer size which is internal to
  * Curl_infof(). If that buffer is changed in size, this tests needs to be
@@ -101,6 +92,15 @@ static int verify(const char *info, const char *two)
 
 UNITTEST_START
 
+#if defined(__GNUC__) && !defined(__clang__)
+#pragma GCC diagnostic push
+#pragma GCC diagnostic ignored "-Wformat"
+#pragma GCC diagnostic ignored "-Wformat-zero-length"
+#if __GNUC__ >= 7
+#pragma GCC diagnostic ignored "-Wformat-overflow"
+#endif
+#endif
+
 /* Injecting a simple short string via a format */
 msnprintf(input, sizeof(input), "Simple Test");
 Curl_infof(testdata, "%s", input);
@@ -146,8 +146,8 @@ Curl_infof(testdata, "%s", input);
 fail_unless(strlen(output) == 2051, "Truncation of infof input 3");
 fail_unless(output[sizeof(output) - 1] == '\0', "Truncation of infof input 3");
 
-UNITTEST_STOP
+#if defined(__GNUC__) && !defined(__clang__)
-
-#ifdef __GNUC__
 #pragma GCC diagnostic pop
 #endif
+
+UNITTEST_STOP

tests/unit/unit2604.c

@@ -46,7 +46,7 @@ struct set {
 UNITTEST_START
 #ifdef USE_SSH
 {
-#ifdef __GNUC__
+#if defined(__GNUC__) || defined(__clang__)
 #pragma GCC diagnostic push
 #pragma GCC diagnostic ignored "-Woverlength-strings"
 #endif
@@ -78,7 +78,7 @@ UNITTEST_START
     { NULL, NULL, NULL, NULL, CURLE_OK }
   };
 
-#ifdef __GNUC__
+#if defined(__GNUC__) || defined(__clang__)
 #pragma GCC diagnostic warning "-Woverlength-strings"
 #endif
 
@@ -114,6 +114,10 @@ UNITTEST_START
 
   free((void *)list[0].cp);
 }
+#if defined(__GNUC__) || defined(__clang__)
+#pragma GCC diagnostic pop
+#endif
+
 #endif
 
 UNITTEST_STOP

tests/unit/unit3200.c

@@ -47,7 +47,7 @@ static CURLcode unit_stop(void)
   return CURLE_OK;
 }
 
-#ifdef __GNUC__
+#if defined(__GNUC__) || defined(__clang__)
 #pragma GCC diagnostic push
 #pragma GCC diagnostic ignored "-Woverlength-strings"
 #endif
@@ -78,7 +78,7 @@ static const char *filecontents[] = {
   "LINE1\x1aTEST"
 };
 
-#ifdef __GNUC__
+#if defined(__GNUC__) || defined(__clang__)
 #pragma GCC diagnostic warning "-Woverlength-strings"
 #endif
 
@@ -173,7 +173,7 @@ UNITTEST_START
   return (CURLcode)rc;
 UNITTEST_STOP
 
-#ifdef __GNUC__
+#if defined(__GNUC__) || defined(__clang__)
 #pragma GCC diagnostic pop
 #endif