[PATCH] perf: build reproducibility improvements

[Denys Zagorui <dzagorui@cisco.com>]

This patch helps to make perf build more reproducible

It seems there is some need to have an ability to invoke
perf from build directory without installation
(84cfac7f05e1: perf tools: Set and pass DOCDIR to builtin-report.c)
DOCDIR contains an absolute path to kernel source directory.
In such case this path can be determined in runtime by using
/proc/self/exe link. In case of building perf with O=
Documentation/tips.txt can be copied to output directory.

There is also python binding test where PYTHONPATH is used to store
absolute path to python/perf.so library. This path can be
also determined in runtime.

bison stores full paths in generated files. This can be
remapped by using --file-prefix-map option that is available
starting from version 3.6.3.

Signed-off-by: Denys Zagorui <dzagorui@cisco.com>
---
 tools/lib/subcmd/exec-cmd.c   | 21 +++++++++++++++++++++
 tools/lib/subcmd/exec-cmd.h   |  1 +
 tools/perf/Build              |  1 -
 tools/perf/Makefile.perf      |  3 +++
 tools/perf/builtin-report.c   | 21 ++++++++++++++++++---
 tools/perf/tests/Build        |  2 +-
 tools/perf/tests/python-use.c | 14 +++++++++++++-
 tools/perf/util/Build         | 10 +++++++---
 8 files changed, 64 insertions(+), 9 deletions(-)

diff --git a/tools/lib/subcmd/exec-cmd.c b/tools/lib/subcmd/exec-cmd.c
index 33e94fb83986..9c293a810159 100644
--- a/tools/lib/subcmd/exec-cmd.c
+++ b/tools/lib/subcmd/exec-cmd.c
@@ -208,3 +208,24 @@ int execl_cmd(const char *cmd,...)
 	argv[argc] = NULL;
 	return execv_cmd(argv);
 }
+
+/* The caller is responsible to free the returned buffer */
+char *get_exec_abs_path(void)
+{
+	int ret;
+	int i;
+	char *buf;
+
+	buf = malloc(PATH_MAX);
+	ret = readlink("/proc/self/exe", buf, PATH_MAX - 1);
+	if (ret <= 0) {
+		free(buf);
+		return NULL;
+	}
+
+	for (i = ret - 1; buf[i] != '/'; i--)
+		; /* just counting */
+	buf[i + 1] = 0;
+
+	return buf;
+}
diff --git a/tools/lib/subcmd/exec-cmd.h b/tools/lib/subcmd/exec-cmd.h
index aba591b8d254..9dc98248dadf 100644
--- a/tools/lib/subcmd/exec-cmd.h
+++ b/tools/lib/subcmd/exec-cmd.h
@@ -13,5 +13,6 @@ extern int execl_cmd(const char *cmd, ...);
 /* get_argv_exec_path and system_path return malloc'd string, caller must free it */
 extern char *get_argv_exec_path(void);
 extern char *system_path(const char *path);
+extern char *get_exec_abs_path(void);
 
 #endif /* __SUBCMD_EXEC_CMD_H */
diff --git a/tools/perf/Build b/tools/perf/Build
index db61dbe2b543..56d0189f1029 100644
--- a/tools/perf/Build
+++ b/tools/perf/Build
@@ -45,7 +45,6 @@ CFLAGS_perf.o              += -DPERF_HTML_PATH="BUILD_STR($(htmldir_SQ))"	\
 			      -DPREFIX="BUILD_STR($(prefix_SQ))"
 CFLAGS_builtin-trace.o	   += -DSTRACE_GROUPS_DIR="BUILD_STR($(STRACE_GROUPS_DIR_SQ))"
 CFLAGS_builtin-report.o	   += -DTIPDIR="BUILD_STR($(tipdir_SQ))"
-CFLAGS_builtin-report.o	   += -DDOCDIR="BUILD_STR($(srcdir_SQ)/Documentation)"
 
 perf-y += util/
 perf-y += arch/
diff --git a/tools/perf/Makefile.perf b/tools/perf/Makefile.perf
index f6e609673de2..2bebff69b064 100644
--- a/tools/perf/Makefile.perf
+++ b/tools/perf/Makefile.perf
@@ -627,6 +627,9 @@ $(OUTPUT)python/perf.so: $(PYTHON_EXT_SRCS) $(PYTHON_EXT_DEPS) $(LIBTRACEEVENT_D
 	  --quiet build_ext; \
 	cp $(PYTHON_EXTBUILD_LIB)perf*.so $(OUTPUT)python/
 
+_dummy := $(shell [ -d '$(OUTPUT)Documentation' ] || mkdir -p '$(OUTPUT)Documentation' && \
+		cp '$(srcdir)/Documentation/tips.txt' '$(OUTPUT)Documentation/')
+
 please_set_SHELL_PATH_to_a_more_modern_shell:
 	$(Q)$$(:)
 
diff --git a/tools/perf/builtin-report.c b/tools/perf/builtin-report.c
index 2a845d6cac09..d9441055357e 100644
--- a/tools/perf/builtin-report.c
+++ b/tools/perf/builtin-report.c
@@ -610,12 +610,27 @@ static int report__browse_hists(struct report *rep)
 	struct perf_session *session = rep->session;
 	struct evlist *evlist = session->evlist;
 	const char *help = perf_tip(system_path(TIPDIR));
+	char *exec_path;
+	char *docdir;
 
 	if (help == NULL) {
 		/* fallback for people who don't install perf ;-) */
-		help = perf_tip(DOCDIR);
-		if (help == NULL)
-			help = "Cannot load tips.txt file, please install perf!";
+		exec_path = get_exec_abs_path();
+		if (exec_path == NULL || asprintf(&docdir, "%sDocumentation", exec_path) < 0) {
+			docdir = NULL;
+			help = "Not enough memory or some other internal error occurred!";
+		}
+
+		if (docdir != NULL) {
+			help = perf_tip(docdir);
+			if (help == NULL)
+				help = "Cannot load tips.txt file, please install perf!";
+		}
+
+		if (exec_path)
+			free(exec_path);
+		if (docdir)
+			free(docdir);
 	}
 
 	switch (use_browser) {
diff --git a/tools/perf/tests/Build b/tools/perf/tests/Build
index 650aec19d490..a20098dcdbc4 100644
--- a/tools/perf/tests/Build
+++ b/tools/perf/tests/Build
@@ -98,5 +98,5 @@ perf-$(CONFIG_DWARF_UNWIND) += dwarf-unwind.o
 endif
 
 CFLAGS_attr.o         += -DBINDIR="BUILD_STR($(bindir_SQ))" -DPYTHON="BUILD_STR($(PYTHON_WORD))"
-CFLAGS_python-use.o   += -DPYTHONPATH="BUILD_STR($(OUTPUT)python)" -DPYTHON="BUILD_STR($(PYTHON_WORD))"
+CFLAGS_python-use.o   += -DPYTHON="BUILD_STR($(PYTHON_WORD))"
 CFLAGS_dwarf-unwind.o += -fno-optimize-sibling-calls
diff --git a/tools/perf/tests/python-use.c b/tools/perf/tests/python-use.c
index 98c6d474aa6f..8b4865c90d5d 100644
--- a/tools/perf/tests/python-use.c
+++ b/tools/perf/tests/python-use.c
@@ -8,16 +8,28 @@
 #include <linux/compiler.h>
 #include "tests.h"
 #include "util/debug.h"
+#include <subcmd/exec-cmd.h>
 
 int test__python_use(struct test *test __maybe_unused, int subtest __maybe_unused)
 {
 	char *cmd;
 	int ret;
+	char *exec_path = NULL;
+	char *pythonpath;
+
+	exec_path = get_exec_abs_path();
+	if (exec_path == NULL)
+		return -1;
+
+	if (asprintf(&pythonpath, "%spython", exec_path) < 0)
+		return -1;
 
 	if (asprintf(&cmd, "echo \"import sys ; sys.path.append('%s'); import perf\" | %s %s",
-		     PYTHONPATH, PYTHON, verbose > 0 ? "" : "2> /dev/null") < 0)
+		     pythonpath, PYTHON, verbose > 0 ? "" : "2> /dev/null") < 0)
 		return -1;
 
+	free(exec_path);
+	free(pythonpath);
 	pr_debug("python usage test: \"%s\"\n", cmd);
 	ret = system(cmd) ? -1 : 0;
 	free(cmd);
diff --git a/tools/perf/util/Build b/tools/perf/util/Build
index e3e12f9d4733..05454c6340e5 100644
--- a/tools/perf/util/Build
+++ b/tools/perf/util/Build
@@ -197,6 +197,10 @@ CFLAGS_llvm-utils.o += -DPERF_INCLUDE_DIR="BUILD_STR($(perf_include_dir_SQ))"
 # avoid compiler warnings in 32-bit mode
 CFLAGS_genelf_debug.o  += -Wno-packed
 
+ifeq ($(shell expr $(shell $(BISON) --version | grep bison | sed -e 's/.\+ \([0-9]\+\).\([0-9]\+\).\([0-9]\+\)/\1\2\3/g') \>\= 363), 1)
+  BISON_FILE_PREFIX_MAP := --file-prefix-map=$(OUTPUT)=
+endif
+
 $(OUTPUT)util/parse-events-flex.c $(OUTPUT)util/parse-events-flex.h: util/parse-events.l $(OUTPUT)util/parse-events-bison.c
 	$(call rule_mkdir)
 	$(Q)$(call echo-cmd,flex)$(FLEX) -o $(OUTPUT)util/parse-events-flex.c \
@@ -204,7 +208,7 @@ $(OUTPUT)util/parse-events-flex.c $(OUTPUT)util/parse-events-flex.h: util/parse-
 
 $(OUTPUT)util/parse-events-bison.c $(OUTPUT)util/parse-events-bison.h: util/parse-events.y
 	$(call rule_mkdir)
-	$(Q)$(call echo-cmd,bison)$(BISON) -v $< -d $(PARSER_DEBUG_BISON) \
+	$(Q)$(call echo-cmd,bison)$(BISON) -v $< -d $(PARSER_DEBUG_BISON) $(BISON_FILE_PREFIX_MAP) \
 		-o $(OUTPUT)util/parse-events-bison.c -p parse_events_
 
 $(OUTPUT)util/expr-flex.c $(OUTPUT)util/expr-flex.h: util/expr.l $(OUTPUT)util/expr-bison.c
@@ -214,7 +218,7 @@ $(OUTPUT)util/expr-flex.c $(OUTPUT)util/expr-flex.h: util/expr.l $(OUTPUT)util/e
 
 $(OUTPUT)util/expr-bison.c $(OUTPUT)util/expr-bison.h: util/expr.y
 	$(call rule_mkdir)
-	$(Q)$(call echo-cmd,bison)$(BISON) -v $< -d $(PARSER_DEBUG_BISON) \
+	$(Q)$(call echo-cmd,bison)$(BISON) -v $< -d $(PARSER_DEBUG_BISON) $(BISON_FILE_PREFIX_MAP) \
 		-o $(OUTPUT)util/expr-bison.c -p expr_
 
 $(OUTPUT)util/pmu-flex.c $(OUTPUT)util/pmu-flex.h: util/pmu.l $(OUTPUT)util/pmu-bison.c
@@ -224,7 +228,7 @@ $(OUTPUT)util/pmu-flex.c $(OUTPUT)util/pmu-flex.h: util/pmu.l $(OUTPUT)util/pmu-
 
 $(OUTPUT)util/pmu-bison.c $(OUTPUT)util/pmu-bison.h: util/pmu.y
 	$(call rule_mkdir)
-	$(Q)$(call echo-cmd,bison)$(BISON) -v $< -d $(PARSER_DEBUG_BISON) \
+	$(Q)$(call echo-cmd,bison)$(BISON) -v $< -d $(PARSER_DEBUG_BISON) $(BISON_FILE_PREFIX_MAP) \
 		-o $(OUTPUT)util/pmu-bison.c -p perf_pmu_
 
 FLEX_GE_26 := $(shell expr $(shell $(FLEX) --version | sed -e  's/flex \([0-9]\+\).\([0-9]\+\)/\1\2/g') \>\= 26)
-- 
2.23.1