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authorBen Gainey <ben.gainey@arm.com>2017-11-22 18:25:41 -0600
committerArnaldo Carvalho de Melo <acme@redhat.com>2017-12-18 11:54:08 -0300
commitca58d7e64bdfc54f7dfe46713c1e2acc68d7522d (patch)
tree678bafe4111a7268c5cdf0dee1845a21875ee68d /tools/arch
parent61fb26a6a23c0f1a07a0f8a11b54bafb1ac2398b (diff)
perf jvmti: Generate correct debug information for inlined code
tools/perf/jvmti is broken in so far as it generates incorrect debug information. Specifically it attributes all debug lines to the original method being output even in the case that some code is being inlined from elsewhere. This patch fixes the issue. To test (from within linux/tools/perf): export JDIR=/usr/lib/jvm/java-8-openjdk-amd64/ make cat << __EOF > Test.java public class Test { private StringBuilder b = new StringBuilder(); private void loop(int i, String... args) { for (String a : args) b.append(a); long hc = b.hashCode() * System.nanoTime(); b = new StringBuilder(); b.append(hc); System.out.printf("Iteration %d = %d\n", i, hc); } public void run(String... args) { for (int i = 0; i < 10000; ++i) { loop(i, args); } } public static void main(String... args) { Test t = new Test(); t.run(args); } } __EOF $JDIR/bin/javac Test.java ./perf record -F 10000 -g -k mono $JDIR/bin/java -agentpath:`pwd`/libperf-jvmti.so Test ./perf inject --jit -i perf.data -o perf.data.jitted ./perf annotate -i perf.data.jitted --stdio | grep Test\.java: | sort -u Before this patch, Test.java line numbers get reported that are greater than the number of lines in the Test.java file. They come from the source file of the inlined function, e.g. java/lang/String.java:1085. For further validation one can examine those lines in the JDK source distribution and confirm that they map to inlined functions called by Test.java. After this patch, the filename of the inlined function is output rather than the incorrect original source filename. Signed-off-by: Ben Gainey <ben.gainey@arm.com> Tested-by: Arnaldo Carvalho de Melo <acme@redhat.com> Tested-by: Stephane Eranian <eranian@google.com> Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com> Cc: Ben Gainey <ben.gainey@arm.com> Cc: Colin King <colin.king@canonical.com> Cc: Darren Hart <dvhart@infradead.org> Cc: Jiri Olsa <jolsa@redhat.com> Cc: Namhyung Kim <namhyung@kernel.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Fixes: 598b7c6919c7 ("perf jit: add source line info support") Link: http://lkml.kernel.org/r/20171122182541.d25599a3eb1ada3480d142fa@arm.com Signed-off-by: Kim Phillips <kim.phillips@arm.com> Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
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