fix: Don't add additional depend mode options after Clang -- option

With the depend mode enabled, ccache executes the original command line
verbatim, potentially with the addition of a few extra options. However,
for clang or clang-cl it is not possible to simply append the additional
options to the end of the original command line since there may be a
"--" option to indicate the end of options.

Fix this by inserting the additional options directly after the compiler
instead of at the end.

Fixes #1273.

2 files changed, 16 insertions, 1 deletions

diff --git a/src/ccache.cpp b/src/ccache.cpp
index 9547f538..71ea532e 100644
--- a/src/ccache.cpp
+++ b/src/ccache.cpp
@@ -1103,7 +1103,9 @@ to_cache(Context& ctx,
     // mode.
     Args depend_mode_args = ctx.orig_args;
     depend_mode_args.erase_with_prefix("--ccache-");
-    depend_mode_args.push_back(depend_extra_args);
+    // Add depend_mode_args directly after the compiler. We can't add them last
+    // since options then may be placed after a "--" option.
+    depend_mode_args.insert(1, depend_extra_args);
     add_prefix(ctx, depend_mode_args, ctx.config.prefix_command());
 
     ctx.time_of_compilation = util::TimePoint::now();
diff --git a/test/suites/depend.bash b/test/suites/depend.bash
index 03a14af6..37cff130 100644
--- a/test/suites/depend.bash
+++ b/test/suites/depend.bash
@@ -357,4 +357,17 @@ EOF
     expect_stat preprocessed_cache_hit 0
     expect_stat cache_miss 1
     expect_equal_content 'file with$special#characters.d' reference.d
+
+    # -------------------------------------------------------------------------
+    if touch empty.c && $COMPILER -c -- empty.c 2>/dev/null; then
+        TEST "--"
+
+        $CCACHE_COMPILE -c -- test.c
+        expect_stat direct_cache_hit 0
+        expect_stat cache_miss 1
+
+        $CCACHE_COMPILE -c -- test.c
+        expect_stat direct_cache_hit 1
+        expect_stat cache_miss 1
+    fi
 }