try_compile: Add options to specify language standards

Give `try_compile` callers a way to control the `CXX_STANDARD`,
`CXX_STANDARD_REQUIRED`, and `CXX_EXTENSIONS` properties of the
generated test target (or the `C` equivalents) in order to compile a
test source for a particular language standard.

Issue: #16456

15 files changed, 124 insertions, 0 deletions

diff --git a/Tests/RunCMake/CMakeLists.txt b/Tests/RunCMake/CMakeLists.txt
index c02b917..1b88d46 100644
--- a/Tests/RunCMake/CMakeLists.txt
+++ b/Tests/RunCMake/CMakeLists.txt
@@ -215,6 +215,18 @@ add_RunCMake_test(project -DCMake_TEST_RESOURCES=${CMake_TEST_RESOURCES})
 add_RunCMake_test(return)
 add_RunCMake_test(set_property)
 add_RunCMake_test(string)
+foreach(var
+    CMAKE_C_COMPILER_ID
+    CMAKE_C_COMPILER_VERSION
+    CMAKE_C_STANDARD_DEFAULT
+    CMAKE_CXX_COMPILER_ID
+    CMAKE_CXX_COMPILER_VERSION
+    CMAKE_CXX_STANDARD_DEFAULT
+    )
+  if(DEFINED ${var})
+    list(APPEND try_compile_ARGS -D${var}=${${var}})
+  endif()
+endforeach()
 add_RunCMake_test(try_compile)
 add_RunCMake_test(try_run)
 add_RunCMake_test(set)
diff --git a/Tests/RunCMake/try_compile/CStandard-result.txt b/Tests/RunCMake/try_compile/CStandard-result.txt
new file mode 100644
index 0000000..d00491f
--- /dev/null
+++ b/Tests/RunCMake/try_compile/CStandard-result.txt
@@ -0,0 +1 @@
+1
diff --git a/Tests/RunCMake/try_compile/CStandard-stderr.txt b/Tests/RunCMake/try_compile/CStandard-stderr.txt
new file mode 100644
index 0000000..209afcc
--- /dev/null
+++ b/Tests/RunCMake/try_compile/CStandard-stderr.txt
@@ -0,0 +1,7 @@
+^CMake Error at .*/Tests/RunCMake/try_compile/CStandard-build/CMakeFiles/CMakeTmp/CMakeLists.txt:[0-9]+ \(add_executable\):
+  C_STANDARD is set to invalid value '3'
++
+CMake Error at CStandard.cmake:[0-9]+ \(try_compile\):
+  Failed to generate test project build system.
+Call Stack \(most recent call first\):
+  CMakeLists.txt:[0-9]+ \(include\)$
diff --git a/Tests/RunCMake/try_compile/CStandard.cmake b/Tests/RunCMake/try_compile/CStandard.cmake
new file mode 100644
index 0000000..2849ed4
--- /dev/null
+++ b/Tests/RunCMake/try_compile/CStandard.cmake
@@ -0,0 +1,7 @@
+enable_language(C)
+try_compile(result ${CMAKE_CURRENT_BINARY_DIR}
+  SOURCES ${CMAKE_CURRENT_SOURCE_DIR}/src.c
+  C_STANDARD 3
+  OUTPUT_VARIABLE out
+  )
+message("try_compile output:\n${out}")
diff --git a/Tests/RunCMake/try_compile/CStandardGNU.c b/Tests/RunCMake/try_compile/CStandardGNU.c
new file mode 100644
index 0000000..ac26c15
--- /dev/null
+++ b/Tests/RunCMake/try_compile/CStandardGNU.c
@@ -0,0 +1,10 @@
+#if __STDC_VERSION__ != 199901L
+#error "Not GNU C 99 mode!"
+#endif
+#ifndef __STRICT_ANSI__
+#error "Not GNU C strict ANSI!"
+#endif
+int main(void)
+{
+  return 0;
+}
diff --git a/Tests/RunCMake/try_compile/CStandardGNU.cmake b/Tests/RunCMake/try_compile/CStandardGNU.cmake
new file mode 100644
index 0000000..29ce315
--- /dev/null
+++ b/Tests/RunCMake/try_compile/CStandardGNU.cmake
@@ -0,0 +1,11 @@
+enable_language(C)
+try_compile(result ${CMAKE_CURRENT_BINARY_DIR}
+  SOURCES ${CMAKE_CURRENT_SOURCE_DIR}/CStandardGNU.c
+  C_STANDARD 99
+  C_STANDARD_REQUIRED 1
+  C_EXTENSIONS 0
+  OUTPUT_VARIABLE out
+  )
+if(NOT result)
+  message(FATAL_ERROR "try_compile failed:\n${out}")
+endif()
diff --git a/Tests/RunCMake/try_compile/CStandardNoDefault.cmake b/Tests/RunCMake/try_compile/CStandardNoDefault.cmake
new file mode 100644
index 0000000..97e72ea
--- /dev/null
+++ b/Tests/RunCMake/try_compile/CStandardNoDefault.cmake
@@ -0,0 +1,9 @@
+enable_language(C)
+try_compile(result ${CMAKE_CURRENT_BINARY_DIR}
+  SOURCES ${CMAKE_CURRENT_SOURCE_DIR}/src.c
+  C_STANDARD 3 # bogus, but not used
+  OUTPUT_VARIABLE out
+  )
+if(NOT result)
+  message(FATAL_ERROR "try_compile failed:\n${out}")
+endif()
diff --git a/Tests/RunCMake/try_compile/CxxStandard-result.txt b/Tests/RunCMake/try_compile/CxxStandard-result.txt
new file mode 100644
index 0000000..d00491f
--- /dev/null
+++ b/Tests/RunCMake/try_compile/CxxStandard-result.txt
@@ -0,0 +1 @@
+1
diff --git a/Tests/RunCMake/try_compile/CxxStandard-stderr.txt b/Tests/RunCMake/try_compile/CxxStandard-stderr.txt
new file mode 100644
index 0000000..ec7245f
--- /dev/null
+++ b/Tests/RunCMake/try_compile/CxxStandard-stderr.txt
@@ -0,0 +1,7 @@
+^CMake Error at .*/Tests/RunCMake/try_compile/CxxStandard-build/CMakeFiles/CMakeTmp/CMakeLists.txt:[0-9]+ \(add_executable\):
+  CXX_STANDARD is set to invalid value '3'
++
+CMake Error at CxxStandard.cmake:[0-9]+ \(try_compile\):
+  Failed to generate test project build system.
+Call Stack \(most recent call first\):
+  CMakeLists.txt:[0-9]+ \(include\)$
diff --git a/Tests/RunCMake/try_compile/CxxStandard.cmake b/Tests/RunCMake/try_compile/CxxStandard.cmake
new file mode 100644
index 0000000..bcb49b9
--- /dev/null
+++ b/Tests/RunCMake/try_compile/CxxStandard.cmake
@@ -0,0 +1,7 @@
+enable_language(CXX)
+try_compile(result ${CMAKE_CURRENT_BINARY_DIR}
+  SOURCES ${CMAKE_CURRENT_SOURCE_DIR}/src.cxx
+  CXX_STANDARD 3
+  OUTPUT_VARIABLE out
+  )
+message("try_compile output:\n${out}")
diff --git a/Tests/RunCMake/try_compile/CxxStandardGNU.cmake b/Tests/RunCMake/try_compile/CxxStandardGNU.cmake
new file mode 100644
index 0000000..cc16bea
--- /dev/null
+++ b/Tests/RunCMake/try_compile/CxxStandardGNU.cmake
@@ -0,0 +1,11 @@
+enable_language(CXX)
+try_compile(result ${CMAKE_CURRENT_BINARY_DIR}
+  SOURCES ${CMAKE_CURRENT_SOURCE_DIR}/CxxStandardGNU.cxx
+  CXX_STANDARD 11
+  CXX_STANDARD_REQUIRED 1
+  CXX_EXTENSIONS 0
+  OUTPUT_VARIABLE out
+  )
+if(NOT result)
+  message(FATAL_ERROR "try_compile failed:\n${out}")
+endif()
diff --git a/Tests/RunCMake/try_compile/CxxStandardGNU.cxx b/Tests/RunCMake/try_compile/CxxStandardGNU.cxx
new file mode 100644
index 0000000..7990a78
--- /dev/null
+++ b/Tests/RunCMake/try_compile/CxxStandardGNU.cxx
@@ -0,0 +1,11 @@
+#if __cplusplus != 201103L &&                                                 \
+  !(__cplusplus < 201103L && defined(__GXX_EXPERIMENTAL_CXX0X__))
+#error "Not GNU C++ 11 mode!"
+#endif
+#ifndef __STRICT_ANSI__
+#error "Not GNU C++ strict ANSI!"
+#endif
+int main()
+{
+  return 0;
+}
diff --git a/Tests/RunCMake/try_compile/CxxStandardNoDefault.cmake b/Tests/RunCMake/try_compile/CxxStandardNoDefault.cmake
new file mode 100644
index 0000000..35caa9d
--- /dev/null
+++ b/Tests/RunCMake/try_compile/CxxStandardNoDefault.cmake
@@ -0,0 +1,9 @@
+enable_language(CXX)
+try_compile(result ${CMAKE_CURRENT_BINARY_DIR}
+  SOURCES ${CMAKE_CURRENT_SOURCE_DIR}/src.cxx
+  CXX_STANDARD 3 # bogus, but not used
+  OUTPUT_VARIABLE out
+  )
+if(NOT result)
+  message(FATAL_ERROR "try_compile failed:\n${out}")
+endif()
diff --git a/Tests/RunCMake/try_compile/RunCMakeTest.cmake b/Tests/RunCMake/try_compile/RunCMakeTest.cmake
index 4934bcd..dadcf35 100644
--- a/Tests/RunCMake/try_compile/RunCMakeTest.cmake
+++ b/Tests/RunCMake/try_compile/RunCMakeTest.cmake
@@ -25,6 +25,23 @@ run_cmake(TargetTypeExe)
 run_cmake(TargetTypeInvalid)
 run_cmake(TargetTypeStatic)
 
+if(CMAKE_C_STANDARD_DEFAULT)
+  run_cmake(CStandard)
+elseif(DEFINED CMAKE_C_STANDARD_DEFAULT)
+  run_cmake(CStandardNoDefault)
+endif()
+if(CMAKE_CXX_STANDARD_DEFAULT)
+  run_cmake(CxxStandard)
+elseif(DEFINED CMAKE_CXX_STANDARD_DEFAULT)
+  run_cmake(CxxStandardNoDefault)
+endif()
+if(CMAKE_C_COMPILER_ID STREQUAL "GNU" AND NOT CMAKE_C_COMPILER_VERSION VERSION_LESS 4.4)
+  run_cmake(CStandardGNU)
+endif()
+if(CMAKE_CXX_COMPILER_ID STREQUAL "GNU" AND NOT CMAKE_CXX_COMPILER_VERSION VERSION_LESS 4.4)
+  run_cmake(CxxStandardGNU)
+endif()
+
 run_cmake(CMP0056)
 run_cmake(CMP0066)
 
diff --git a/Tests/RunCMake/try_compile/src.cxx b/Tests/RunCMake/try_compile/src.cxx
new file mode 100644
index 0000000..f8b643a
--- /dev/null
+++ b/Tests/RunCMake/try_compile/src.cxx
@@ -0,0 +1,4 @@
+int main()
+{
+  return 0;
+}