try_compile: Add SOURCE_FROM_FILE

Add ability to copy try_compile (and try_run) source files from
arbitrary locations into the operation directory. This is included for
the sake of completion and consolidation, although use cases which
actually require this may be rare.

Help/command/try_compile.rst

@@ -58,7 +58,8 @@ Try Compiling Source Files
   try_compile(<resultVar>
               <SOURCES <srcfile...>]             |
                SOURCE_FROM_ARG <name> <content>] |
-               SOURCE_FROM_VAR <name> <var>]     >...
+               SOURCE_FROM_VAR <name> <var>]     |
+               SOURCE_FROM_FILE <name> <path>    >...
               [CMAKE_FLAGS <flags>...]
               [COMPILE_DEFINITIONS <defs>...]
               [LINK_OPTIONS <options>...]
@@ -178,6 +179,16 @@ The options are:
 
   ``SOURCE_FROM_ARG`` may be specified multiple times.
 
+``SOURCE_FROM_FILE <name> <path>``
+  .. versionadded:: 3.25
+
+  Copy ``<path>`` to a file named ``<name>`` in the operation directory. This
+  can be used to consolidate files into the operation directory, which may be
+  useful if a source which already exists (i.e. as a stand-alone file in a
+  project's source repository) needs to refer to other file(s) created by
+  ``SOURCE_FROM_*``. (Otherwise, ``SOURCES`` is usually more convenient.) The
+  specified ``<name>`` is not allowed to contain path components.
+
 ``SOURCE_FROM_VAR <name> <content>``
   .. versionadded:: 3.25
 

Help/command/try_run.rst

@@ -15,7 +15,8 @@ Try Compiling and Running Source Files
   try_run(<runResultVar> <compileResultVar>
           <SOURCES <srcfile...>]             |
            SOURCE_FROM_ARG <name> <content>] |
-           SOURCE_FROM_VAR <name> <var>]     >...
+           SOURCE_FROM_VAR <name> <var>]     |
+           SOURCE_FROM_FILE <name> <path>    >...
           [CMAKE_FLAGS <flags>...]
           [COMPILE_DEFINITIONS <defs>...]
           [LINK_OPTIONS <options>...]

Source/cmCoreTryCompile.cxx

@@ -174,6 +174,7 @@ auto const TryCompileBaseNewSourcesArgParser =
   cmArgumentParser<Arguments>{ TryCompileBaseSourcesArgParser }
     .Bind("SOURCE_FROM_ARG"_s, &Arguments::SourceFromArg)
     .Bind("SOURCE_FROM_VAR"_s, &Arguments::SourceFromVar)
+    .Bind("SOURCE_FROM_FILE"_s, &Arguments::SourceFromFile)
   /* keep semicolon on own line */;
 
 auto const TryCompileBaseProjectArgParser =
@@ -416,6 +417,12 @@ bool cmCoreTryCompile::TryCompileCode(Arguments& arguments,
         "SOURCE_FROM_VAR requires exactly two arguments");
       return false;
     }
+    if (arguments.SourceFromFile && arguments.SourceFromFile->size() % 2) {
+      this->Makefile->IssueMessage(
+        MessageType::FATAL_ERROR,
+        "SOURCE_FROM_FILE requires exactly two arguments");
+      return false;
+    }
   } else {
     // only valid for srcfile signatures
     if (!arguments.LangProps.empty()) {
@@ -497,6 +504,31 @@ bool cmCoreTryCompile::TryCompileCode(Arguments& arguments,
         sources.emplace_back(std::move(out));
       }
     }
+    if (arguments.SourceFromFile) {
+      auto const k = arguments.SourceFromFile->size();
+      for (auto i = decltype(k){ 0 }; i < k; i += 2) {
+        const auto& dst = (*arguments.SourceFromFile)[i + 0];
+        const auto& src = (*arguments.SourceFromFile)[i + 1];
+
+        if (!cmSystemTools::GetFilenamePath(dst).empty()) {
+          const auto& msg =
+            cmStrCat("SOURCE_FROM_FILE given invalid filename \"", dst, "\"");
+          this->Makefile->IssueMessage(MessageType::FATAL_ERROR, msg);
+          return false;
+        }
+
+        auto dstPath = cmStrCat(this->BinaryDirectory, "/", dst);
+        auto const result = cmSystemTools::CopyFileAlways(src, dstPath);
+        if (!result.IsSuccess()) {
+          const auto& msg = cmStrCat("SOURCE_FROM_FILE failed to copy \"", src,
+                                     "\": ", result.GetString());
+          this->Makefile->IssueMessage(MessageType::FATAL_ERROR, msg);
+          return false;
+        }
+
+        sources.emplace_back(std::move(dstPath));
+      }
+    }
     // TODO: ensure sources is not empty
 
     // Detect languages to enable.

Source/cmCoreTryCompile.h

@@ -44,6 +44,8 @@ public:
       SourceFromArg;
     cm::optional<ArgumentParser::NonEmpty<std::vector<std::string>>>
       SourceFromVar;
+    cm::optional<ArgumentParser::NonEmpty<std::vector<std::string>>>
+      SourceFromFile;
     ArgumentParser::MaybeEmpty<std::vector<std::string>> CMakeFlags{
       1, "CMAKE_FLAGS"
     }; // fake argv[0]

Tests/RunCMake/try_compile/RunCMakeTest.cmake

@@ -23,6 +23,7 @@ unset(RunCMake_TEST_OPTIONS)
 run_cmake(SourceFromOneArg)
 run_cmake(SourceFromThreeArgs)
 run_cmake(SourceFromBadName)
+run_cmake(SourceFromBadFile)
 
 run_cmake(ProjectCopyFile)
 run_cmake(NonSourceCopyFile)

Tests/RunCMake/try_compile/SourceFromBadFile-result.txt

@@ -0,0 +1 @@
+1

Tests/RunCMake/try_compile/SourceFromBadFile-stderr.txt

@@ -0,0 +1,4 @@
+CMake Error at SourceFromBadFile.cmake:[0-9]+ \(try_compile\):
+  SOURCE_FROM_FILE failed to copy "bad#source.c": No such file or directory
+Call Stack \(most recent call first\):
+  CMakeLists.txt:3 \(include\)

Tests/RunCMake/try_compile/SourceFromBadFile.cmake

@@ -0,0 +1 @@
+try_compile(RESULT SOURCE_FROM_FILE bad.c "bad#source.c")

Tests/TryCompile/CMakeLists.txt

@@ -89,6 +89,12 @@ if(SHOULD_FAIL_DUE_TO_EMPTY_SOURCE)
   message(SEND_ERROR "Trying to compile an empty source succeeded?")
 endif()
 
+# try to compile a copied source
+try_compile(SHOULD_PASS
+  SOURCE_FROM_FILE pass.c ${TryCompile_SOURCE_DIR}/pass.c
+  OUTPUT_VARIABLE TRY_OUT)
+EXPECT_COMPILED("SOURCE_FROM_FILE" SHOULD_PASS "${TRY_OUT}")
+
 # try to run a source specified directly
 set(TRY_RUN_MAIN_CODE
   "extern int answer(); \n"