From dea57aa1cd879df4feae1b9595b38c5b6ff74574 Mon Sep 17 00:00:00 2001
From: Bruce Ashfield <bruce.ashfield@gmail.com>
Date: Tue, 9 Mar 2021 14:23:36 -0500
Subject: perf: fix reproducibility issues

perf has been failing our reproducible testing due to multiple symbols
containg build paths.

With this commit, we fix the issues:

 1) The following line in the Makefle:

     override PYTHON := $(call get-executable-or-default,PYTHON,$(PYTHON_AUTO))

 "PYTHON" / "PYTHON_AUTO" have the full path as part of the variable. We've
 ensure that the environment is setup and we do not need the full path to be
 captured, since the symbol gets built into the executable, making it not
 reproducible.

 2) The following line:

    srcdir_SQ = $(patsubst %tools/perf,tools/perf,$(subst ','\'',$(srcdir))),

 Captures the full src path of perf, which of course makes it not
 reproducible. We really only need the relative location 'tools/perf', so we
 change the Makefile line to remove everything before 'tools/perf'

 3) OUTPUT is the full path, we have python on the path so we remove it from the
 definition. This is captured in the perf binary, so breaks reproducibility

     PYTHONPATH="BUILD_STR(python)

 4) To avoid bison generating #ifdefs that have captured paths, we make sure
 all the calls have YFLAGS, which contains prefix mapping information.

Upstream-status: OE specific to our cross/build environments. Variants
                 will be developed for upstream

Signed-off-by: Bruce Ashfield <bruce.ashfield@gmail.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>
---
 meta/recipes-kernel/perf/perf.bb | 38 ++++++++++++++++++++++++++++++++++++++
 1 file changed, 38 insertions(+)

diff --git a/meta/recipes-kernel/perf/perf.bb b/meta/recipes-kernel/perf/perf.bb
index 868cde7353..2beb404c03 100644
--- a/meta/recipes-kernel/perf/perf.bb
+++ b/meta/recipes-kernel/perf/perf.bb
@@ -81,6 +81,7 @@ EXTRA_OEMAKE = '\
     AR="${AR}" \
     LD="${LD}" \
     EXTRA_CFLAGS="-ldw" \
+    YFLAGS='-y --file-prefix-map=${WORKDIR}=/usr/src/debug/${PN}/${EXTENDPE}${PV}-${PR}' \
     EXTRA_LDFLAGS="${PERF_EXTRA_LDFLAGS}" \
     perfexecdir=${libexecdir} \
     NO_GTK2=1 \
@@ -214,6 +215,43 @@ do_configure_prepend () {
             ${S}/tools/build/Makefile.build
     fi
 
+    # start reproducibility substitutions
+    if [ -e "${S}/tools/perf/Makefile.config" ]; then
+        # The following line in the Makefle:
+        #     override PYTHON := $(call get-executable-or-default,PYTHON,$(PYTHON_AUTO))
+        # "PYTHON" / "PYTHON_AUTO" have the full path as part of the variable. We've
+        # ensure that the environment is setup and we do not need the full path to be
+        # captured, since the symbol gets built into the executable, making it not
+        # reproducible.
+        sed -i -e 's,$(call get-executable-or-default\,PYTHON\,$(PYTHON_AUTO)),$(notdir $(call get-executable-or-default\,PYTHON\,$(PYTHON_AUTO))),g' \
+            ${S}/tools/perf/Makefile.config
+
+        # The following line:
+        #     srcdir_SQ = $(patsubst %tools/perf,tools/perf,$(subst ','\'',$(srcdir))),
+        # Captures the full src path of perf, which of course makes it not
+        # reproducible. We really only need the relative location 'tools/perf', so we
+        # change the Makefile line to remove everything before 'tools/perf'
+        sed -i -e "s%srcdir_SQ = \$(subst ','\\\'',\$(srcdir))%srcdir_SQ = \$(patsubst \%tools/perf,tools/perf,\$(subst ','\\\'',\$(srcdir)))%g" \
+            ${S}/tools/perf/Makefile.config
+    fi
+    if [ -e "${S}/tools/perf/tests/Build" ]; then
+        # OUTPUT is the full path, we have python on the path so we remove it from the
+        # definition. This is captured in the perf binary, so breaks reproducibility
+        sed -i -e 's,PYTHONPATH="BUILD_STR($(OUTPUT)python)",PYTHONPATH="BUILD_STR(python)",g' \
+            ${S}/tools/perf/tests/Build
+    fi
+    if [ -e "${S}/tools/perf/util/Build" ]; then
+        # To avoid bison generating #ifdefs that have captured paths, we make sure
+        # all the calls have YFLAGS, which contains prefix mapping information.
+        sed -i -e 's,$(BISON),$(BISON) $(YFLAGS),g' ${S}/tools/perf/util/Build
+    fi
+    if [ -e "${S}/scripts/Makefile.host" ]; then
+        # To avoid yacc (bison) generating #ifdefs that have captured paths, we make sure
+        # all the calls have YFLAGS, which contains prefix mapping information.
+        sed -i -e 's,$(YACC),$(YACC) $(YFLAGS),g' ${S}/scripts/Makefile.host
+    fi
+    # end reproducibility substitutions
+
     # We need to ensure the --sysroot option in CC is preserved
     if [ -e "${S}/tools/perf/Makefile.perf" ]; then
         sed -i 's,CC = $(CROSS_COMPILE)gcc,#CC,' ${S}/tools/perf/Makefile.perf
-- 
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