add_custom_{target,command}: Add argument JOB_SERVER_AWARE

Issue: #16273

8 files changed, 297 insertions, 1 deletions

diff --git a/Tests/RunCMake/CMakeLists.txt b/Tests/RunCMake/CMakeLists.txt
index 8baa98f..584edd7 100644
--- a/Tests/RunCMake/CMakeLists.txt
+++ b/Tests/RunCMake/CMakeLists.txt
@@ -171,8 +171,9 @@ endif()
 if(NOT CMAKE_GENERATOR MATCHES "Visual Studio|Xcode")
   add_RunCMake_test(CMP0065 -DCMAKE_SYSTEM_NAME=${CMAKE_SYSTEM_NAME})
 endif()
+add_executable(detect_jobserver detect_jobserver.c)
 if(CMAKE_GENERATOR MATCHES "Make")
-  add_RunCMake_test(Make -DMAKE_IS_GNU=${MAKE_IS_GNU})
+  add_RunCMake_test(Make -DMAKE_IS_GNU=${MAKE_IS_GNU} -DDETECT_JOBSERVER=$<TARGET_FILE:detect_jobserver>)
 endif()
 unset(ninja_test_with_qt_version)
 unset(ninja_qt_args)
diff --git a/Tests/RunCMake/Make/DetectJobServer-absent-parallel-build-stderr.txt b/Tests/RunCMake/Make/DetectJobServer-absent-parallel-build-stderr.txt
new file mode 100644
index 0000000..c63bde3
--- /dev/null
+++ b/Tests/RunCMake/Make/DetectJobServer-absent-parallel-build-stderr.txt
@@ -0,0 +1 @@
+^(Warning: (Borland's make|NMake|Watcom's WMake) does not support parallel builds\. Ignoring parallel build command line option\.)?$
diff --git a/Tests/RunCMake/Make/DetectJobServer-absent.cmake b/Tests/RunCMake/Make/DetectJobServer-absent.cmake
new file mode 100644
index 0000000..e3dddc0
--- /dev/null
+++ b/Tests/RunCMake/Make/DetectJobServer-absent.cmake
@@ -0,0 +1,13 @@
+# Verifies that the jobserver connection is absent
+add_custom_command(OUTPUT custom_command.txt
+  JOB_SERVER_AWARE OFF
+  COMMENT "Should not detect jobserver"
+  COMMAND ${DETECT_JOBSERVER} --absent "custom_command.txt"
+)
+
+# trigger the custom command to run
+add_custom_target(dummy ALL
+  JOB_SERVER_AWARE OFF
+  DEPENDS ${CMAKE_CURRENT_BINARY_DIR}/custom_command.txt
+  COMMAND ${DETECT_JOBSERVER} --absent "custom_target.txt"
+)
diff --git a/Tests/RunCMake/Make/DetectJobServer-present.cmake b/Tests/RunCMake/Make/DetectJobServer-present.cmake
new file mode 100644
index 0000000..a33658f
--- /dev/null
+++ b/Tests/RunCMake/Make/DetectJobServer-present.cmake
@@ -0,0 +1,13 @@
+# Verifies that the jobserver is present
+add_custom_command(OUTPUT custom_command.txt
+  JOB_SERVER_AWARE ON
+  COMMENT "Should detect jobserver support"
+  COMMAND ${DETECT_JOBSERVER} --present "custom_command.txt"
+)
+
+# trigger the custom command to run
+add_custom_target(dummy ALL
+  JOB_SERVER_AWARE ON
+  DEPENDS ${CMAKE_CURRENT_BINARY_DIR}/custom_command.txt
+  COMMAND ${DETECT_JOBSERVER} --present "custom_target.txt"
+)
diff --git a/Tests/RunCMake/Make/GNUMakeJobServerAware-check.cmake b/Tests/RunCMake/Make/GNUMakeJobServerAware-check.cmake
new file mode 100644
index 0000000..7c5c296
--- /dev/null
+++ b/Tests/RunCMake/Make/GNUMakeJobServerAware-check.cmake
@@ -0,0 +1,12 @@
+# This test verifies that the commands in the generated Makefiles contain the
+# `+` prefix
+function(check_for_plus_prefix target)
+  set(file "${RunCMake_BINARY_DIR}/GNUMakeJobServerAware-build/${target}")
+  file(READ "${file}" build_file)
+  if(NOT "${build_file}" MATCHES [[\+]])
+    message(FATAL_ERROR "The file ${file} does not contain the expected prefix in the custom command.")
+  endif()
+endfunction()
+
+check_for_plus_prefix("CMakeFiles/dummy.dir/build.make")
+check_for_plus_prefix("CMakeFiles/dummy2.dir/build.make")
diff --git a/Tests/RunCMake/Make/GNUMakeJobServerAware.cmake b/Tests/RunCMake/Make/GNUMakeJobServerAware.cmake
new file mode 100644
index 0000000..951c2d7
--- /dev/null
+++ b/Tests/RunCMake/Make/GNUMakeJobServerAware.cmake
@@ -0,0 +1,12 @@
+add_custom_command(
+  OUTPUT "${CMAKE_CURRENT_BINARY_DIR}/custom-command"
+  JOB_SERVER_AWARE ON
+  COMMAND $(CMAKE_COMMAND) -E touch "${CMAKE_CURRENT_BINARY_DIR}/custom-command"
+)
+add_custom_target(dummy ALL DEPENDS "${CMAKE_CURRENT_BINARY_DIR}/custom-command")
+
+add_custom_target(
+  dummy2 ALL
+  JOB_SERVER_AWARE ON
+  COMMAND ${CMAKE_COMMAND} -E true
+)
diff --git a/Tests/RunCMake/Make/RunCMakeTest.cmake b/Tests/RunCMake/Make/RunCMakeTest.cmake
index c7717ec..12904c8 100644
--- a/Tests/RunCMake/Make/RunCMakeTest.cmake
+++ b/Tests/RunCMake/Make/RunCMakeTest.cmake
@@ -70,3 +70,43 @@ if(NOT RunCMake_GENERATOR STREQUAL "Watcom WMake")
   run_CMP0113(OLD)
   run_CMP0113(NEW)
 endif()
+
+function(detect_jobserver_present is_parallel)
+  set(RunCMake_TEST_BINARY_DIR ${RunCMake_BINARY_DIR}/DetectJobServer-present-build)
+  set(RunCMake_TEST_NO_CLEAN 1)
+  set(RunCMake_TEST_OPTIONS "-DDETECT_JOBSERVER=${DETECT_JOBSERVER}")
+  run_cmake(DetectJobServer-present)
+  if (is_parallel)
+    run_cmake_command(DetectJobServer-present-parallel-build ${CMAKE_COMMAND} --build . -j4)
+  else()
+    run_cmake_command(DetectJobServer-present-build ${CMAKE_COMMAND} --build .)
+  endif()
+endfunction()
+
+function(detect_jobserver_absent is_parallel)
+  set(RunCMake_TEST_BINARY_DIR ${RunCMake_BINARY_DIR}/DetectJobServer-absent-build)
+  set(RunCMake_TEST_NO_CLEAN 1)
+  set(RunCMake_TEST_OPTIONS "-DDETECT_JOBSERVER=${DETECT_JOBSERVER}")
+  run_cmake(DetectJobServer-absent)
+  if (is_parallel)
+    run_cmake_command(DetectJobServer-absent-parallel-build ${CMAKE_COMMAND} --build . -j4)
+  else()
+    run_cmake_command(DetectJobServer-absent-build ${CMAKE_COMMAND} --build .)
+  endif()
+endfunction()
+
+# Jobservers are currently only supported by GNU makes, except MSYS2 make
+if(MAKE_IS_GNU AND NOT RunCMake_GENERATOR MATCHES "MSYS Makefiles")
+  detect_jobserver_present(ON)
+else()
+  detect_jobserver_absent(ON)
+endif()
+# No matter which generator is used, the jobserver should not be present if a
+# parallel build is not requested
+detect_jobserver_absent(OFF)
+
+if(MAKE_IS_GNU)
+  # In GNU makes, `JOB_SERVER_AWARE` support is implemented by prefixing
+  # commands with the '+' operator.
+  run_cmake(GNUMakeJobServerAware)
+endif()
diff --git a/Tests/RunCMake/detect_jobserver.c b/Tests/RunCMake/detect_jobserver.c
new file mode 100644
index 0000000..a6c1a7c
--- /dev/null
+++ b/Tests/RunCMake/detect_jobserver.c
@@ -0,0 +1,204 @@
+#ifndef _CRT_SECURE_NO_WARNINGS
+#  define _CRT_SECURE_NO_WARNINGS
+#endif
+
+#if defined(_MSC_VER) && _MSC_VER >= 1928
+#  pragma warning(disable : 5105) /* macro expansion warning in windows.h */
+#endif
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+
+#define MAX_MESSAGE_LENGTH 1023
+#define USAGE "Usage: %s [--present|--absent] <output_file>\n"
+
+// Extracts --jobserver-auth=<string> or --jobserver-fds=<string> from
+// MAKEFLAGS. The returned pointer points to the start of <string> Returns NULL
+// if MAKEFLAGS is not set or does not contain --jobserver-auth or
+// --jobserver-fds
+char* jobserver_auth(char* message)
+{
+  const char* jobserver_auth = "--jobserver-auth=";
+  const char* jobserver_fds = "--jobserver-fds=";
+  char* auth;
+  char* fds;
+  char* start;
+  char* end;
+  char* result;
+  size_t len;
+
+  char* makeflags = getenv("MAKEFLAGS");
+  if (makeflags == NULL) {
+    strncpy(message, "MAKEFLAGS not set", MAX_MESSAGE_LENGTH);
+    return NULL;
+  }
+
+  // write MAKEFLAGS to stdout for debugging
+  fprintf(stdout, "MAKEFLAGS: %s\n", makeflags);
+
+  auth = strstr(makeflags, jobserver_auth);
+  fds = strstr(makeflags, jobserver_fds);
+  if (auth == NULL && fds == NULL) {
+    strncpy(message, "No jobserver found", MAX_MESSAGE_LENGTH);
+    return NULL;
+  } else if (auth != NULL) {
+    start = auth + strlen(jobserver_auth);
+  } else {
+    start = fds + strlen(jobserver_fds);
+  }
+
+  end = strchr(start, ' ');
+  if (end == NULL) {
+    end = start + strlen(start);
+  }
+  len = (size_t)(end - start);
+  result = (char*)malloc(len + 1);
+  strncpy(result, start, len);
+  result[len] = '\0';
+
+  return result;
+}
+
+#if defined(_WIN32)
+#  include <windows.h>
+
+int windows_semaphore(const char* semaphore, char* message)
+{
+  // Open the semaphore
+  HANDLE hSemaphore = OpenSemaphoreA(SEMAPHORE_ALL_ACCESS, FALSE, semaphore);
+
+  if (hSemaphore == NULL) {
+#  if defined(_MSC_VER) && _MSC_VER < 1900
+    sprintf(message, "Error opening semaphore: %s (%ld)\n", semaphore,
+            GetLastError());
+#  else
+    snprintf(message, MAX_MESSAGE_LENGTH,
+             "Error opening semaphore: %s (%ld)\n", semaphore, GetLastError());
+#  endif
+    return 1;
+  }
+
+  strncpy(message, "Success", MAX_MESSAGE_LENGTH);
+  return 0;
+}
+#else
+#  include <errno.h>
+#  include <fcntl.h>
+
+int test_fd(int read_fd, int write_fd, char* message)
+{
+  // Detect if the file descriptors are valid
+  int read_good = fcntl(read_fd, F_GETFD) != -1;
+  int read_error = errno;
+
+  int write_good = fcntl(write_fd, F_GETFD) != -1;
+  int write_error = errno;
+
+  if (!read_good || !write_good) {
+    snprintf(message, MAX_MESSAGE_LENGTH,
+             "Error opening file descriptors: %d (%s), %d (%s)\n", read_fd,
+             strerror(read_error), write_fd, strerror(write_error));
+    return 1;
+  }
+
+  snprintf(message, MAX_MESSAGE_LENGTH, "Success\n");
+  return 0;
+}
+
+int posix(const char* jobserver, char* message)
+{
+  int read_fd;
+  int write_fd;
+  const char* path;
+
+  // First try to parse as "R,W" file descriptors
+  if (sscanf(jobserver, "%d,%d", &read_fd, &write_fd) == 2) {
+    return test_fd(read_fd, write_fd, message);
+  }
+
+  // Then try to parse as "fifo:PATH"
+  if (strncmp(jobserver, "fifo:", 5) == 0) {
+    path = jobserver + 5;
+    read_fd = open(path, O_RDONLY);
+    write_fd = open(path, O_WRONLY);
+    return test_fd(read_fd, write_fd, message);
+  }
+
+  // We don't understand the format
+  snprintf(message, MAX_MESSAGE_LENGTH, "Unrecognized jobserver format: %s\n",
+           jobserver);
+  return 1;
+}
+#endif
+
+// Takes 2 arguments:
+// Either --present or --absent to indicate we expect the jobserver to be
+// "present and valid", or "absent or invalid"
+//
+// if `--present` is passed, the exit code will be 0 if the jobserver is
+// present, 1 if it is absent if `--absent` is passed, the exit code will be 0
+// if the jobserver is absent, 1 if it is present in either case, if there is
+// some fatal error (e.g the output file cannot be opened), the exit code will
+// be 2
+int main(int argc, char** argv)
+{
+  char message[MAX_MESSAGE_LENGTH + 1];
+  char* output_file;
+  FILE* fp;
+  int expecting_present;
+  int expecting_absent;
+  char* jobserver;
+  int result;
+
+  if (argc != 3) {
+    fprintf(stderr, USAGE, argv[0]);
+    return 2;
+  }
+
+  expecting_present = strcmp(argv[1], "--present") == 0;
+  expecting_absent = strcmp(argv[1], "--absent") == 0;
+  if (!expecting_present && !expecting_absent) {
+    fprintf(stderr, USAGE, argv[0]);
+    return 2;
+  }
+
+  output_file = argv[2];
+  fp = fopen(output_file, "w");
+  if (fp == NULL) {
+    fprintf(stderr, "Error opening output file: %s\n", output_file);
+    return 2;
+  }
+
+  jobserver = jobserver_auth(message);
+  if (jobserver == NULL) {
+    if (expecting_absent) {
+      fprintf(stdout, "Success\n");
+      return 0;
+    }
+
+    fprintf(stderr, "%s\n", message);
+    return 1;
+  }
+
+#if defined(_WIN32)
+  result = windows_semaphore(jobserver, message);
+#else
+  result = posix(jobserver, message);
+#endif
+  free(jobserver);
+  message[MAX_MESSAGE_LENGTH] = 0;
+
+  if (result == 0 && expecting_present) {
+    fprintf(stdout, "Success\n");
+    return 0;
+  }
+
+  if (result == 1 && expecting_absent) {
+    fprintf(stdout, "Success\n");
+    return 0;
+  }
+
+  fprintf(stderr, "%s\n", message);
+  return 1;
+}