Hello,
the attached patch adds ccache support for compiler color diagnostics (also
reported by somebody as #10075).
Clang automatically uses colors for output automatically if used in terminal.
Ccache's redirecting to a file disables this. GCC 4.8 has got a similar
support, except that it apparently requires also $GCC_COLORS or an explicit
option.
The patch detects if the compiler would use colors if used without ccache and
explicitly forces an option to achieve this. Note that I do not have GCC 4.8
here, so I tested with Clang's alias and the GCC_COLORS support is done based
on documentation.
Caveats:
- GCC developers decided to roll their own name for the option when
introducing it. Clang has an alias for the GCC way, but versions predating
that obviously can't support it, so it's necessary to detect the compiler. As
ccache doesn't do that (and I don't find it worth much effort, as it can't be
100% reliable anyway), the code merely guesses from the binary name. If the
compiler used will be e.g. the 'cc' symlink, there'll be no colors. No big
deal.
- Since the stderr is different, obviously compiling with and without colors
has different results as well. That means that such a compile
is "duplicated". It's hopefully not such a common case, although it's
perfectly possible. I don't know if it's worth the effort to try to be smart
here. A possibly simple improvement could be to search the cache with and
without the option set and if stderr is empty, reuse the result regardless of
the option. I'm not quite sure where exactly this should happen in the code.
I expect it'd make sense to add $CCACHE_NOCOLORS to disable this support?
I can also create manpage section for this color support, but I first wanted
to check here with the code.
--
Lubos Lunak
From d4284a161e733a68ad1c1c84d124d81d3c627db8 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Lubo=C5=A1=20Lu=C5=88=C3=A1k?= <l.lu...@centrum.cz>
Date: Fri, 29 Nov 2013 12:14:03 +0100
Subject: [PATCH] support compiler color diagnostics if possible
Clang and GCC (starting with 4.8) support color output if possible,
but since ccache redirects stderr to a file, they detect the output
is not a terminal and do not enable colors. Try to detect if colors
would be used and force colors explicitly.
Caveats:
- Compiles with and without colors are considered different from each
other (so they are "duplicated").
- GCC decided to roll its own name for the option, so it's necessary
to guess which compiler is actually used.
---
ccache.c | 72 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
1 file changed, 72 insertions(+)
diff --git a/ccache.c b/ccache.c
index 90c38e7..158ad5e 100644
--- a/ccache.c
+++ b/ccache.c
@@ -1065,6 +1065,24 @@ hash_compiler(struct mdfour *hash, struct stat *st, const char *path,
}
/*
+ * Note that these compiler checks are unreliable, so nothing should hard-depend on them.
+ */
+
+static bool compiler_is_clang()
+{
+ const char* name = strrchr( orig_args->argv[ 0 ], '/' );
+ name = name ? name + 1 : orig_args->argv[ 0 ];
+ return strstr( name, "clang" ) != NULL;
+}
+
+static bool compiler_is_gcc()
+{
+ const char* name = strrchr(orig_args->argv[ 0 ], '/' );
+ name = name ? name + 1 : orig_args->argv[ 0 ];
+ return strstr(name, "gcc") != NULL || strstr(name, "g++") != NULL;
+}
+
+/*
* Update a hash sum with information common for the direct and preprocessor
* modes.
*/
@@ -1128,6 +1146,15 @@ calculate_common_hash(struct args *args, struct mdfour *hash)
}
free(p);
}
+
+ /* Possibly hash GCC_COLORS (for color diagnostics). */
+ if (compiler_is_gcc()) {
+ const char* gcc_colors = getenv("GCC_COLORS");
+ if (gcc_colors != NULL) {
+ hash_delimiter(hash,"gcccolors");
+ hash_string(hash, gcc_colors);
+ }
+ }
}
/*
@@ -1626,6 +1653,13 @@ is_precompiled_header(const char *path)
|| str_eq(get_extension(path), ".pth");
}
+static bool color_output_possible()
+{
+ const char* term_env = getenv("TERM");
+
+ return isatty(STDERR_FILENO) && term_env && strcasecmp(term_env, "DUMB") != 0;
+}
+
/*
* Process the compiler options into options suitable for passing to the
* preprocessor and the real compiler. The preprocessor options don't include
@@ -1654,6 +1688,7 @@ cc_process_args(struct args *args, struct args **preprocessor_args,
int argc;
char **argv;
bool result = true;
+ bool found_color_diagnostics = false;
expanded_args = args_copy(args);
stripped_args = args_init(0, NULL);
@@ -2010,6 +2045,21 @@ cc_process_args(struct args *args, struct args **preprocessor_args,
free(arg);
}
+ if (str_eq(argv[i], "-fcolor-diagnostics")
+ || str_eq(argv[i], "-fno-color-diagnostics")
+ || str_eq(argv[i], "-fdiagnostics-color")
+ || str_eq(argv[i], "-fdiagnostics-color=always")
+ || str_eq(argv[i], "-fno-diagnostics-color")
+ || str_eq(argv[i], "-fdiagnostics-color=never")) {
+ args_add(stripped_args, argv[i]);
+ found_color_diagnostics = true;
+ continue;
+ }
+ if (str_eq(argv[i], "-fdiagnostics-color=auto")) {
+ /* Ignore the option and let automatic color handling below handle this. */
+ continue;
+ }
+
/*
* Options taking an argument that we may want to rewrite to relative paths
* to get better hit rate. A secondary effect is that paths in the standard
@@ -2298,6 +2348,28 @@ cc_process_args(struct args *args, struct args **preprocessor_args,
args_add(cpp_args, explicit_language);
}
+ /*
+ * Since output is redirected, compilers will not color their output by default,
+ * so force it explicitly if it would be otherwise done.
+ */
+ if (!found_color_diagnostics && color_output_possible()) {
+ if (compiler_is_clang()) {
+ args_add(stripped_args, "-fcolor-diagnostics");
+ cc_log("Automatically enabling colors");
+ } else if (compiler_is_gcc()) {
+ /*
+ * GCC has it since 4.8, but that'd require detecting what GCC
+ * version is used for the actual compile. However it requires
+ * also GCC_COLORS to be set (and not empty), so use that
+ * for detecting if GCC would use colors.
+ */
+ if (getenv("GCC_COLORS") != NULL && getenv("GCC_COLORS")[ 0 ] != '\0') {
+ args_add(stripped_args, "-fdiagnostics-color");
+ cc_log("Automatically enabling colors");
+ }
+ }
+ }
+
/*
* Add flags for dependency generation only to the preprocessor command line.
*/
--
1.8.1.4
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