[RFC PATCH v9 24/50] perf tools: Introduce llvm config options

[Wang Nan <wangnan0@huawei.com>]

This patch introduces [llvm] config section with 5 options. Following
patches will use then to config llvm dynamica compiling.

'llvm-utils.[ch]' is introduced in this patch for holding all
llvm/clang related stuffs.

Example:

  [llvm]
        # Path to clang. If omit, search it from $PATH.
	clang-path = "/path/to/clang"

        # Cmdline template. Following line shows its default value.
        # Environment variable is used to passing options.
	clang-bpf-cmd-template = "$CLANG_EXEC $CLANG_OPTIONS \
				  $KERNEL_INC_OPTIONS -Wno-unused-value \
				  -Wno-pointer-sign -working-directory \
				  $WORKING_DIR  -c $CLANG_SOURCE -target \
				  bpf -O2 -o -"

        # Options passed to clang, will be passed to cmdline by
        # $CLANG_OPTIONS.
	clang-opt = "-Wno-unused-value -Wno-pointer-sign"

        # kbuild directory. If not set, use /lib/modules/`uname -r`/build.
        # If set to "" deliberately, skip kernel header auto-detector.
	kbuild-dir = "/path/to/kernel/build"

        # Options passed to 'make' when detecting kernel header options.
	kbuild-opts = "ARCH=x86_64"

Signed-off-by: Wang Nan <wangnan0@huawei.com>
---
 tools/perf/util/Build        |  1 +
 tools/perf/util/config.c     |  4 ++++
 tools/perf/util/llvm-utils.c | 45 ++++++++++++++++++++++++++++++++++++++++++++
 tools/perf/util/llvm-utils.h | 36 +++++++++++++++++++++++++++++++++++
 4 files changed, 86 insertions(+)
 create mode 100644 tools/perf/util/llvm-utils.c
 create mode 100644 tools/perf/util/llvm-utils.h

diff --git a/tools/perf/util/Build b/tools/perf/util/Build
index 586a59d..edd48b5 100644
--- a/tools/perf/util/Build
+++ b/tools/perf/util/Build
@@ -14,6 +14,7 @@ libperf-y += find_next_bit.o
 libperf-y += help.o
 libperf-y += kallsyms.o
 libperf-y += levenshtein.o
+libperf-y += llvm-utils.o
 libperf-y += parse-options.o
 libperf-y += parse-events.o
 libperf-y += path.o
diff --git a/tools/perf/util/config.c b/tools/perf/util/config.c
index e18f653..2e452ac 100644
--- a/tools/perf/util/config.c
+++ b/tools/perf/util/config.c
@@ -12,6 +12,7 @@
 #include "cache.h"
 #include "exec_cmd.h"
 #include "util/hist.h"  /* perf_hist_config */
+#include "util/llvm-utils.h"   /* perf_llvm_config */
 
 #define MAXNAME (256)
 
@@ -408,6 +409,9 @@ int perf_default_config(const char *var, const char *value,
 	if (!prefixcmp(var, "call-graph."))
 		return perf_callchain_config(var, value);
 
+	if (!prefixcmp(var, "llvm."))
+		return perf_llvm_config(var, value);
+
 	/* Add other config variables here. */
 	return 0;
 }
diff --git a/tools/perf/util/llvm-utils.c b/tools/perf/util/llvm-utils.c
new file mode 100644
index 0000000..fd5b1bc
--- /dev/null
+++ b/tools/perf/util/llvm-utils.c
@@ -0,0 +1,45 @@
+/*
+ * Copyright (C) 2015, Wang Nan <wangnan0@huawei.com>
+ * Copyright (C) 2015, Huawei Inc.
+ */
+
+#include <stdio.h>
+#include "util.h"
+#include "debug.h"
+#include "llvm-utils.h"
+#include "cache.h"
+
+#define CLANG_BPF_CMD_DEFAULT_TEMPLATE				\
+		"$CLANG_EXEC $CLANG_OPTIONS $KERNEL_INC_OPTIONS " \
+		"-Wno-unused-value -Wno-pointer-sign "		\
+		"-working-directory $WORKING_DIR "		\
+		" -c \"$CLANG_SOURCE\" -target bpf -O2 -o -"
+
+struct llvm_param llvm_param = {
+	.clang_path = "clang",
+	.clang_bpf_cmd_template = CLANG_BPF_CMD_DEFAULT_TEMPLATE,
+	.clang_opt = NULL,
+	.kbuild_dir = NULL,
+	.kbuild_opts = NULL,
+};
+
+int perf_llvm_config(const char *var, const char *value)
+{
+	if (prefixcmp(var, "llvm."))
+		return 0;
+	var += sizeof("llvm.") - 1;
+
+	if (!strcmp(var, "clang-path"))
+		llvm_param.clang_path = strdup(value);
+	else if (!strcmp(var, "clang-bpf-cmd-template"))
+		llvm_param.clang_bpf_cmd_template = strdup(value);
+	else if (!strcmp(var, "clang-opt"))
+		llvm_param.clang_opt = strdup(value);
+	else if (!strcmp(var, "kbuild-dir"))
+		llvm_param.kbuild_dir = strdup(value);
+	else if (!strcmp(var, "kbuild-opts"))
+		llvm_param.kbuild_opts = strdup(value);
+	else
+		return -1;
+	return 0;
+}
diff --git a/tools/perf/util/llvm-utils.h b/tools/perf/util/llvm-utils.h
new file mode 100644
index 0000000..504b799
--- /dev/null
+++ b/tools/perf/util/llvm-utils.h
@@ -0,0 +1,36 @@
+/*
+ * Copyright (C) 2015, Wang Nan <wangnan0@huawei.com>
+ * Copyright (C) 2015, Huawei Inc.
+ */
+#ifndef __LLVM_UTILS_H
+#define __LLVM_UTILS_H
+
+#include "debug.h"
+
+struct llvm_param {
+	/* Path of clang executable */
+	const char *clang_path;
+	/*
+	 * Template of clang bpf compiling. 5 env variables
+	 * can be used:
+	 *   $CLANG_EXEC:		Path to clang.
+	 *   $CLANG_OPTIONS:		Extra options to clang.
+	 *   $KERNEL_INC_OPTIONS:	Kernel include directories.
+	 *   $WORKING_DIR:		Kernel source directory.
+	 *   $CLANG_SOURCE:		Source file to be compiled.
+	 */
+	const char *clang_bpf_cmd_template;
+	/* Will be filled in $CLANG_OPTIONS */
+	const char *clang_opt;
+	/* Where to find kbuild system */
+	const char *kbuild_dir;
+	/*
+	 * Arguments passed to make, like 'ARCH=arm' if doing cross
+	 * compiling. Should not be used for dynamic compiling.
+	 */
+	const char *kbuild_opts;
+};
+
+extern struct llvm_param llvm_param;
+extern int perf_llvm_config(const char *var, const char *value);
+#endif
-- 
1.8.3.4