chore: add script to trace allocations with Instruments (#16191)

scripts/trace.sh

@@ -0,0 +1,40 @@
+#!/bin/bash
+
+# @file trace.sh
+# @summary build + run bun with Instruments. All args are forwarded to `bun-debug`.
+#
+# @description
+# This script builds bun, signs it with debug entitlements, and runs it with an
+# Allocations template. After running, a `.trace` folder will be created. Open
+# it with `open foo.trace` to view it in Instruments.
+#
+# This script requires xcode command line tools to be installed and only works
+# on MacOS.
+
+set -e -o pipefail
+
+BUN="bun-debug"
+DEBUG_BUN="build/debug/${BUN}"
+
+file_to_run=$1
+if [[ -z $file_to_run ]]; then
+  echo "Usage: $0 <file_to_run> [bun args]"
+  echo "       $0 test <file_to_run> [bun args]"
+  exit 1
+fi
+
+bun run build
+
+echo "Signing bun binary..."
+codesign --entitlements $(realpath entitlements.debug.plist) --force --timestamp --sign - -vvvv --deep --strict ${DEBUG_BUN}
+
+export BUN_JSC_logJITCodeForPerf=1
+export BUN_JSC_collectExtraSamplingProfilerData=1
+export BUN_JSC_sampleCCode=1
+export BUN_JSC_alwaysGeneratePCToCodeOriginMap=1
+
+echo "Tracing ${file_to_run}..."
+xcrun xctrace record --template "Allocations" -output . --launch -- "./${DEBUG_BUN}" $file_to_run
+# perf record -k 1 --sample-cpu -e cycles:u -j any --call-graph dwarf,16384 -F 499 -p (pgrep -f "${BUN}")
+
+# DEBUGINFOD_URLS="" perf inject --jit --input perf.data --output=perf.jit.data -v