[PATCH] scripts/decode_stacktrace.sh: Support LLVM addr2line

[Bjorn Andersson <quic_bjorande@quicinc.com>]

The kernel build system adhere to the LLVM environment variable, to
select building the kernel using clang/llvm. In combination with the
ARCH environment variable the kernel can be cross-compiled without the
user specifying the CROSS_COMPILE variable.

The LLVM environment variable is used to specify the suffix of the llvm
executables (such as LLVM=-12 for llvm-addr2line-12), or to omit the
suffix when set to "1" (e.g. llvm-addr2line).

decode_stacktrace.sh allows invoking a specific addr2line executable by
prefixing the command with CROSS_COMPILE. At best allows the user to
trick decode_stacktrace.sh into invoking llvm-addr2line, and it does not
support specifying an alternative version based on the suffix.

Teach decode_stacktrace.sh about the two cases of the LLVM environment
variable, and use this to determine which addr2line to use. The current
behavior is maintained when the LLVM variable is not set.

Signed-off-by: Bjorn Andersson <quic_bjorande@quicinc.com>
---
 scripts/decode_stacktrace.sh | 9 ++++++++-
 1 file changed, 8 insertions(+), 1 deletion(-)

diff --git a/scripts/decode_stacktrace.sh b/scripts/decode_stacktrace.sh
index 564c5632e1a2..adf1d64477a1 100755
--- a/scripts/decode_stacktrace.sh
+++ b/scripts/decode_stacktrace.sh
@@ -16,6 +16,13 @@ elif type c++filt >/dev/null 2>&1 ; then
 	cppfilt_opts=-i
 fi
 
+# Determine which addr2line to use
+case "$LLVM" in
+	""	) addr2line="${CROSS_COMPILE}addr2line";;
+	"1"	) addr2line="llvm-addr2line";;
+	*	) addr2line="llvm-addr2line${LLVM}";;
+esac
+
 if [[ $1 == "-r" ]] ; then
 	vmlinux=""
 	basepath="auto"
@@ -169,7 +176,7 @@ parse_symbol() {
 	if [[ $aarray_support == true && "${cache[$module,$address]+isset}" == "isset" ]]; then
 		local code=${cache[$module,$address]}
 	else
-		local code=$(${CROSS_COMPILE}addr2line -i -e "$objfile" "$address" 2>/dev/null)
+		local code=$(${addr2line} -i -e "$objfile" "$address" 2>/dev/null)
 		if [[ $aarray_support == true ]]; then
 			cache[$module,$address]=$code
 		fi

---
base-commit: 39676dfe52331dba909c617f213fdb21015c8d10
change-id: 20231225-decode-stacktrace-llvm-f260a1614361

Best regards,
-- 
Bjorn Andersson <quic_bjorande@quicinc.com>