perf python: Port arm-cs-trace-disasm to perf module

Port arm-cs-trace-disasm.py to a standalone script in tools/perf/python/
using the perf module directly.

Improvements compared to the legacy script:
- Encapsulate trace disassembly state in a TraceDisasm class.
- Default to itrace="b" when creating perf.session() (overridable via
  --itrace or PERF_ITRACE) so all CoreSight branch samples are
  synthesized without requiring --itrace=b on the command line.
- Automatically search standard kernel debug paths (find_vmlinux())
  when -k/--vmlinux is not specified, and query
  perf.config_get("annotate.objdump") for the default objdump binary.
- Bound DISASM_CACHE memory consumption by evicting the cache at 1024
  entries and skipping caching of oversized (> 512 lines) objdump
  outputs.
- Use sample.srccode() from the perf extension module to annotate
  disassembly output with source filenames, line numbers, and source
  lines.

Update the ARM CoreSight disassembly shell test
(test_arm_coresight_disasm.sh) to invoke the standalone script.

Assisted-by: Antigravity:gemini-3.1-pro
Reviewed-by: James Clark <james.clark@linaro.org>
Signed-off-by: Ian Rogers <irogers@google.com>
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

1 files changed, 18 insertions, 7 deletions

diff --git a/tools/perf/tests/shell/coresight/test_arm_coresight_disasm.sh b/tools/perf/tests/shell/coresight/test_arm_coresight_disasm.sh
index f3ebad596378..82cdb1762285 100755
--- a/tools/perf/tests/shell/coresight/test_arm_coresight_disasm.sh
+++ b/tools/perf/tests/shell/coresight/test_arm_coresight_disasm.sh
@@ -1,6 +1,6 @@
 #!/bin/bash
-# Check Arm CoreSight disassembly script completes without errors (exclusive)
 # SPDX-License-Identifier: GPL-2.0
+# Check Arm CoreSight disassembly script completes without errors (exclusive)
 
 # The disassembly script reconstructs ranges of instructions and gives these to objdump to
 # decode. objdump doesn't like ranges that go backwards, but these are a good indication
@@ -20,11 +20,23 @@ skip_if_no_cs_etm_event || exit 2
 set -e
 glb_err=1
 
+# Relative path works whether it's installed or running from repo
+if [ -n "$PERF_EXEC_PATH" ] && [ -e "$PERF_EXEC_PATH/python/arm-cs-trace-disasm.py" ]; then
+	script_path="$PERF_EXEC_PATH/python/arm-cs-trace-disasm.py"
+else
+	script_path=$(dirname "$0")/../../../python/arm-cs-trace-disasm.py
+fi
+
+# shellcheck source=lib/setup_python.sh
+. "$(dirname "$0")"/../lib/setup_python.sh
+$PYTHON -c "import perf" 2>/dev/null || {
+	echo "Skipping test, perf python module not found"
+	exit 2
+}
+
 perfdata_dir=$(mktemp -d /tmp/__perf_test.perf.data.XXXXX)
 perfdata=${perfdata_dir}/perf.data
 file=$(mktemp /tmp/temporary_file.XXXXX)
-# Relative path works whether it's installed or running from repo
-script_path=$(dirname "$0")/../../../scripts/python/arm-cs-trace-disasm.py
 
 cleanup_files()
 {
@@ -44,8 +56,8 @@ branch_search='[[:space:]](bl|b(\.(eq|ne|cs|cc|mi|pl|vs|vc|hi|ls|ge|lt|gt|le|al)
 if [ "$(id -u)" == 0 ] && [ -e /proc/kcore ]; then
 	echo "Testing kernel disassembly"
 	perf record -o ${perfdata} -e cs_etm//k --kcore -Se -m,64K -- touch $file > /dev/null 2>&1
-	perf script -i ${perfdata} --itrace=b -s python:${script_path} -- \
-		-d --stop-sample=2 -k ${perfdata}/kcore_dir/kcore 2> /dev/null > ${file}
+	$PYTHON ${script_path} -i ${perfdata} -d --stop-sample=2 \
+		-k ${perfdata}/kcore_dir/kcore 2> /dev/null > ${file}
 	grep -q -E ${branch_search} ${file}
 	echo "Found kernel branches"
 else
@@ -56,8 +68,7 @@ fi
 ## Test user ##
 echo "Testing userspace disassembly"
 perf record -o ${perfdata} -e cs_etm//u -Se -m,64K -- touch $file > /dev/null 2>&1
-perf script -i ${perfdata} --itrace=b -s python:${script_path} -- \
-	-d --stop-sample=2 2> /dev/null > ${file}
+$PYTHON ${script_path} -i ${perfdata} -d --stop-sample=2 2> /dev/null > ${file}
 grep -q -E ${branch_search} ${file}
 echo "Found userspace branches"