cmake/Source/cmTryRunCommand.cxx

/* Distributed under the OSI-approved BSD 3-Clause License.  See accompanying
   file Copyright.txt or https://cmake.org/licensing for details.  */
#include "cmTryRunCommand.h"

#include <cstdio>

#include "cmsys/FStream.hxx"

#include "cmDuration.h"
#include "cmMakefile.h"
#include "cmMessageType.h"
#include "cmRange.h"
#include "cmState.h"
#include "cmStateTypes.h"
#include "cmStringAlgorithms.h"
#include "cmSystemTools.h"
#include "cmake.h"

class cmExecutionStatus;

// cmTryRunCommand
bool cmTryRunCommand::InitialPass(std::vector<std::string> const& argv,
                                  cmExecutionStatus&)
{
  if (argv.size() < 4) {
    return false;
  }

  if (this->Makefile->GetCMakeInstance()->GetWorkingMode() ==
      cmake::FIND_PACKAGE_MODE) {
    this->Makefile->IssueMessage(
      MessageType::FATAL_ERROR,
      "The TRY_RUN() command is not supported in --find-package mode.");
    return false;
  }

  // build an arg list for TryCompile and extract the runArgs,
  std::vector<std::string> tryCompile;

  this->CompileResultVariable.clear();
  this->RunResultVariable.clear();
  this->OutputVariable.clear();
  this->RunOutputVariable.clear();
  this->CompileOutputVariable.clear();

  std::string runArgs;
  unsigned int i;
  for (i = 1; i < argv.size(); ++i) {
    if (argv[i] == "ARGS") {
      ++i;
      while (i < argv.size() && argv[i] != "COMPILE_DEFINITIONS" &&
             argv[i] != "CMAKE_FLAGS" && argv[i] != "LINK_OPTIONS" &&
             argv[i] != "LINK_LIBRARIES") {
        runArgs += " ";
        runArgs += argv[i];
        ++i;
      }
      if (i < argv.size()) {
        tryCompile.push_back(argv[i]);
      }
    } else {
      if (argv[i] == "OUTPUT_VARIABLE") {
        if (argv.size() <= (i + 1)) {
          cmSystemTools::Error(
            "OUTPUT_VARIABLE specified but there is no variable");
          return false;
        }
        i++;
        this->OutputVariable = argv[i];
      } else if (argv[i] == "RUN_OUTPUT_VARIABLE") {
        if (argv.size() <= (i + 1)) {
          cmSystemTools::Error(
            "RUN_OUTPUT_VARIABLE specified but there is no variable");
          return false;
        }
        i++;
        this->RunOutputVariable = argv[i];
      } else if (argv[i] == "COMPILE_OUTPUT_VARIABLE") {
        if (argv.size() <= (i + 1)) {
          cmSystemTools::Error(
            "COMPILE_OUTPUT_VARIABLE specified but there is no variable");
          return false;
        }
        i++;
        this->CompileOutputVariable = argv[i];
      } else {
        tryCompile.push_back(argv[i]);
      }
    }
  }

  // although they could be used together, don't allow it, because
  // using OUTPUT_VARIABLE makes crosscompiling harder
  if (!this->OutputVariable.empty() &&
      (!this->RunOutputVariable.empty() ||
       !this->CompileOutputVariable.empty())) {
    cmSystemTools::Error(
      "You cannot use OUTPUT_VARIABLE together with COMPILE_OUTPUT_VARIABLE "
      "or RUN_OUTPUT_VARIABLE. Please use only COMPILE_OUTPUT_VARIABLE and/or "
      "RUN_OUTPUT_VARIABLE.");
    return false;
  }

  bool captureRunOutput = false;
  if (!this->OutputVariable.empty()) {
    captureRunOutput = true;
    tryCompile.emplace_back("OUTPUT_VARIABLE");
    tryCompile.push_back(this->OutputVariable);
  }
  if (!this->CompileOutputVariable.empty()) {
    tryCompile.emplace_back("OUTPUT_VARIABLE");
    tryCompile.push_back(this->CompileOutputVariable);
  }
  if (!this->RunOutputVariable.empty()) {
    captureRunOutput = true;
  }

  this->RunResultVariable = argv[0];
  this->CompileResultVariable = argv[1];

  // do the try compile
  int res = this->TryCompileCode(tryCompile, true);

  // now try running the command if it compiled
  if (!res) {
    if (this->OutputFile.empty()) {
      cmSystemTools::Error(this->FindErrorMessage);
    } else {
      // "run" it and capture the output
      std::string runOutputContents;
      if (this->Makefile->IsOn("CMAKE_CROSSCOMPILING") &&
          !this->Makefile->IsDefinitionSet("CMAKE_CROSSCOMPILING_EMULATOR")) {
        this->DoNotRunExecutable(
          runArgs, argv[3], captureRunOutput ? &runOutputContents : nullptr);
      } else {
        this->RunExecutable(runArgs, &runOutputContents);
      }

      // now put the output into the variables
      if (!this->RunOutputVariable.empty()) {
        this->Makefile->AddDefinition(this->RunOutputVariable,
                                      runOutputContents);
      }

      if (!this->OutputVariable.empty()) {
        // if the TryCompileCore saved output in this outputVariable then
        // prepend that output to this output
        const char* compileOutput =
          this->Makefile->GetDefinition(this->OutputVariable);
        if (compileOutput) {
          runOutputContents = compileOutput + runOutputContents;
        }
        this->Makefile->AddDefinition(this->OutputVariable, runOutputContents);
      }
    }
  }

  // if we created a directory etc, then cleanup after ourselves
  if (!this->Makefile->GetCMakeInstance()->GetDebugTryCompile()) {
    this->CleanupFiles(this->BinaryDirectory);
  }
  return true;
}

void cmTryRunCommand::RunExecutable(const std::string& runArgs,
                                    std::string* out)
{
  int retVal = -1;

  std::string finalCommand;
  const std::string& emulator =
    this->Makefile->GetSafeDefinition("CMAKE_CROSSCOMPILING_EMULATOR");
  if (!emulator.empty()) {
    std::vector<std::string> emulatorWithArgs = cmExpandedList(emulator);
    finalCommand +=
      cmSystemTools::ConvertToRunCommandPath(emulatorWithArgs[0]);
    finalCommand += " ";
    for (std::string const& arg : cmMakeRange(emulatorWithArgs).advance(1)) {
      finalCommand += "\"";
      finalCommand += arg;
      finalCommand += "\"";
      finalCommand += " ";
    }
  }
  finalCommand += cmSystemTools::ConvertToRunCommandPath(this->OutputFile);
  if (!runArgs.empty()) {
    finalCommand += runArgs;
  }
  bool worked = cmSystemTools::RunSingleCommand(
    finalCommand, out, out, &retVal, nullptr, cmSystemTools::OUTPUT_NONE,
    cmDuration::zero());
  // set the run var
  char retChar[16];
  const char* retStr;
  if (worked) {
    sprintf(retChar, "%i", retVal);
    retStr = retChar;
  } else {
    retStr = "FAILED_TO_RUN";
  }
  this->Makefile->AddCacheDefinition(this->RunResultVariable, retStr,
                                     "Result of TRY_RUN",
                                     cmStateEnums::INTERNAL);
}

/* This is only used when cross compiling. Instead of running the
 executable, two cache variables are created which will hold the results
 the executable would have produced.
*/
void cmTryRunCommand::DoNotRunExecutable(const std::string& runArgs,
                                         const std::string& srcFile,
                                         std::string* out)
{
  // copy the executable out of the CMakeFiles/ directory, so it is not
  // removed at the end of TRY_RUN and the user can run it manually
  // on the target platform.
  std::string copyDest =
    cmStrCat(this->Makefile->GetHomeOutputDirectory(), "/CMakeFiles/",
             cmSystemTools::GetFilenameWithoutExtension(this->OutputFile), '-',
             this->RunResultVariable,
             cmSystemTools::GetFilenameExtension(this->OutputFile));
  cmSystemTools::CopyFileAlways(this->OutputFile, copyDest);

  std::string resultFileName =
    cmStrCat(this->Makefile->GetHomeOutputDirectory(), "/TryRunResults.cmake");

  std::string detailsString = cmStrCat("For details see ", resultFileName);

  std::string internalRunOutputName =
    this->RunResultVariable + "__TRYRUN_OUTPUT";
  bool error = false;

  if (!this->Makefile->GetDefinition(this->RunResultVariable)) {
    // if the variables doesn't exist, create it with a helpful error text
    // and mark it as advanced
    std::string comment =
      cmStrCat("Run result of TRY_RUN(), indicates whether the executable "
               "would have been able to run on its target platform.\n",
               detailsString);
    this->Makefile->AddCacheDefinition(this->RunResultVariable,
                                       "PLEASE_FILL_OUT-FAILED_TO_RUN",
                                       comment.c_str(), cmStateEnums::STRING);

    cmState* state = this->Makefile->GetState();
    const char* existingValue =
      state->GetCacheEntryValue(this->RunResultVariable);
    if (existingValue) {
      state->SetCacheEntryProperty(this->RunResultVariable, "ADVANCED", "1");
    }

    error = true;
  }

  // is the output from the executable used ?
  if (out) {
    if (!this->Makefile->GetDefinition(internalRunOutputName)) {
      // if the variables doesn't exist, create it with a helpful error text
      // and mark it as advanced
      std::string comment = cmStrCat(
        "Output of TRY_RUN(), contains the text, which the executable "
        "would have printed on stdout and stderr on its target platform.\n",
        detailsString);

      this->Makefile->AddCacheDefinition(
        internalRunOutputName, "PLEASE_FILL_OUT-NOTFOUND", comment.c_str(),
        cmStateEnums::STRING);
      cmState* state = this->Makefile->GetState();
      const char* existing = state->GetCacheEntryValue(internalRunOutputName);
      if (existing) {
        state->SetCacheEntryProperty(internalRunOutputName, "ADVANCED", "1");
      }

      error = true;
    }
  }

  if (error) {
    static bool firstTryRun = true;
    cmsys::ofstream file(resultFileName.c_str(),
                         firstTryRun ? std::ios::out : std::ios::app);
    if (file) {
      if (firstTryRun) {
        /* clang-format off */
        file << "# This file was generated by CMake because it detected "
                "TRY_RUN() commands\n"
                "# in crosscompiling mode. It will be overwritten by the next "
                "CMake run.\n"
                "# Copy it to a safe location, set the variables to "
                "appropriate values\n"
                "# and use it then to preset the CMake cache (using -C).\n\n";
        /* clang-format on */
      }

      std::string comment =
        cmStrCat('\n', this->RunResultVariable,
                 "\n   indicates whether the executable would have been able "
                 "to run on its\n"
                 "   target platform. If so, set ",
                 this->RunResultVariable,
                 " to\n"
                 "   the exit code (in many cases 0 for success), otherwise "
                 "enter \"FAILED_TO_RUN\".\n");
      if (out) {
        comment += internalRunOutputName;
        comment +=
          "\n   contains the text the executable "
          "would have printed on stdout and stderr.\n"
          "   If the executable would not have been able to run, set ";
        comment += internalRunOutputName;
        comment += " empty.\n"
                   "   Otherwise check if the output is evaluated by the "
                   "calling CMake code. If so,\n"
                   "   check what the source file would have printed when "
                   "called with the given arguments.\n";
      }
      comment += "The ";
      comment += this->CompileResultVariable;
      comment += " variable holds the build result for this TRY_RUN().\n\n"
                 "Source file   : ";
      comment += srcFile + "\n";
      comment += "Executable    : ";
      comment += copyDest + "\n";
      comment += "Run arguments : ";
      comment += runArgs;
      comment += "\n";
      comment += "   Called from: " + this->Makefile->FormatListFileStack();
      cmsys::SystemTools::ReplaceString(comment, "\n", "\n# ");
      file << comment << "\n\n";

      file << "set( " << this->RunResultVariable << " \n     \""
           << this->Makefile->GetDefinition(this->RunResultVariable)
           << "\"\n     CACHE STRING \"Result from TRY_RUN\" FORCE)\n\n";

      if (out) {
        file << "set( " << internalRunOutputName << " \n     \""
             << this->Makefile->GetDefinition(internalRunOutputName)
             << "\"\n     CACHE STRING \"Output from TRY_RUN\" FORCE)\n\n";
      }
      file.close();
    }
    firstTryRun = false;

    std::string errorMessage =
      cmStrCat("TRY_RUN() invoked in cross-compiling mode, "
               "please set the following cache variables "
               "appropriately:\n   ",
               this->RunResultVariable, " (advanced)\n");
    if (out) {
      errorMessage += "   " + internalRunOutputName + " (advanced)\n";
    }
    errorMessage += detailsString;
    cmSystemTools::Error(errorMessage);
    return;
  }

  if (out) {
    (*out) = this->Makefile->GetDefinition(internalRunOutputName);
  }
}