Fix removal of -MMD option when running the preprocessor

Usually, the `preproc.macros` recipe includes the C/C++ flags, and
through that the `-MMD` flag to generate dependency files. However,
since include detection passed an output file of `/dev/null` (or the
equivalent on other operating systems), this causes gcc to try and
generate a `/dev/null.d` file and fail.

To prevent this, the `-MMD` flag was filtered out, but this filtering
was applied to the `compiler.cpp.flags` variable, where it *usually*
comes from. However, this is not necessarily true for all platforms. For
example, the PIC32 platform used to have this flag in the
`compiler.c.flags` variable and have `compiler.cpp.flags` include that.
This prevented the flag from being filtered away and caused a failure.

Due to previous changes, it is now possible for this filtering to happen
after all variables have been replaced and the command to run was
generated, but before actually running it. An extra advantage is that
the filtering is more robust than the previous substring-based
filtering.

This fixes arduino#230.

Signed-off-by: Matthijs Kooijman <[email protected]>

Author: matthijskooijman

Diff for: builder_utils/utils.go

@@ -430,10 +430,6 @@ func PrepareCommandForRecipe(ctx *types.Context, buildProperties properties.Map,
 	return command, nil
 }
 
-func RemoveHyphenMDDFlagFromGCCCommandLine(buildProperties properties.Map) {
-	buildProperties[constants.BUILD_PROPERTIES_COMPILER_CPP_FLAGS] = strings.Replace(buildProperties[constants.BUILD_PROPERTIES_COMPILER_CPP_FLAGS], "-MMD", "", -1)
-}
-
 // CopyFile copies the contents of the file named src to the file named
 // by dst. The file will be created if it does not already exist. If the
 // destination file exists, all it's contents will be replaced by the contents

Diff for: gcc_preproc_runner.go

@@ -30,6 +30,7 @@
 package builder
 
 import (
+	"os/exec"
 	"strings"
 
 	"github.com/arduino/arduino-builder/builder_utils"
@@ -41,12 +42,12 @@ import (
 )
 
 func GCCPreprocRunner(ctx *types.Context, sourceFilePath string, targetFilePath string, includes []string) error {
-	properties, err := prepareGCCPreprocRecipeProperties(ctx, sourceFilePath, targetFilePath, includes)
+	cmd, err := prepareGCCPreprocRecipeProperties(ctx, sourceFilePath, targetFilePath, includes)
 	if err != nil {
 		return i18n.WrapError(err)
 	}
 
-	_, _, err = builder_utils.ExecRecipe(ctx, properties, constants.RECIPE_PREPROC_MACROS, true, /* stdout */ utils.ShowIfVerbose, /* stderr */ utils.Show)
+	_, _, err = utils.ExecCommand(ctx, cmd /* stdout */, utils.ShowIfVerbose /* stderr */, utils.Show)
 	if err != nil {
 		return i18n.WrapError(err)
 	}
@@ -55,34 +56,42 @@ func GCCPreprocRunner(ctx *types.Context, sourceFilePath string, targetFilePath
 }
 
 func GCCPreprocRunnerForDiscoveringIncludes(ctx *types.Context, sourceFilePath string, targetFilePath string, includes []string) ([]byte, error) {
-	properties, err := prepareGCCPreprocRecipeProperties(ctx, sourceFilePath, targetFilePath, includes)
+	cmd, err := prepareGCCPreprocRecipeProperties(ctx, sourceFilePath, targetFilePath, includes)
 	if err != nil {
 		return nil, i18n.WrapError(err)
 	}
 
-	_, stderr, err := builder_utils.ExecRecipe(ctx, properties, constants.RECIPE_PREPROC_MACROS, true, /* stdout */ utils.ShowIfVerbose, /* stderr */ utils.Capture)
+	_, stderr, err := utils.ExecCommand(ctx, cmd /* stdout */, utils.ShowIfVerbose /* stderr */, utils.Capture)
 	if err != nil {
 		return stderr, i18n.WrapError(err)
 	}
 
 	return stderr, nil
 }
 
-func prepareGCCPreprocRecipeProperties(ctx *types.Context, sourceFilePath string, targetFilePath string, includes []string) (properties.Map, error) {
+func prepareGCCPreprocRecipeProperties(ctx *types.Context, sourceFilePath string, targetFilePath string, includes []string) (*exec.Cmd, error) {
 	properties := ctx.BuildProperties.Clone()
 	properties[constants.BUILD_PROPERTIES_SOURCE_FILE] = sourceFilePath
 	properties[constants.BUILD_PROPERTIES_PREPROCESSED_FILE_PATH] = targetFilePath
 
 	includes = utils.Map(includes, utils.WrapWithHyphenI)
 	properties[constants.BUILD_PROPERTIES_INCLUDES] = strings.Join(includes, constants.SPACE)
-	builder_utils.RemoveHyphenMDDFlagFromGCCCommandLine(properties)
 
 	if properties[constants.RECIPE_PREPROC_MACROS] == constants.EMPTY_STRING {
 		//generate PREPROC_MACROS from RECIPE_CPP_PATTERN
 		properties[constants.RECIPE_PREPROC_MACROS] = GeneratePreprocPatternFromCompile(properties[constants.RECIPE_CPP_PATTERN])
 	}
 
-	return properties, nil
+	cmd, err := builder_utils.PrepareCommandForRecipe(ctx, properties, constants.RECIPE_PREPROC_MACROS, true)
+	if err != nil {
+		return nil, i18n.WrapError(err)
+	}
+
+	// Remove -MMD argument if present. Leaving it will make gcc try
+	// to create a /dev/null.d dependency file, which won't work.
+	cmd.Args = utils.Filter(cmd.Args, func(a string) bool { return a != "-MMD" })
+
+	return cmd, nil
 }
 
 func GeneratePreprocPatternFromCompile(compilePattern string) string {