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For a Java method signature like:
Ljava/lang/AbstractStringBuilder;appendChars(Ljava/lang/String;II)V
The demangler produces:
void class java.lang.AbstractStringBuilder.appendChars(class java.lang., shorttring., int, int)
The arguments should be (java.lang.String, int, int) but the demangler
interprets the "S" in String as the type code for "short". Correct this
and two other minor things:
- There is no "bool" type in Java, should be "boolean".
- The demangler prepends "class" to every Java class name. This is not
standard Java syntax and it wastes a lot of horizontal space if the
signature is long. Remove this as there isn't any ambiguity between
class names and primitives.
Committer notes:
This was split from a larger patch that also added a java demangler
'perf test' entry, that, before this patch shows the error being fixed
by it:
$ perf test java
65: Demangle Java : FAILED!
$ perf test -v java
Couldn't bump rlimit(MEMLOCK), failures may take place when creating BPF maps, etc
65: Demangle Java :
--- start ---
test child forked, pid 307264
FAILED: Ljava/lang/StringLatin1;equals([B[B)Z: bool class java.lang.StringLatin1.equals(byte[], byte[]) != boolean java.lang.StringLatin1.equals(byte[], byte[])
FAILED: Ljava/util/zip/ZipUtils;CENSIZ([BI)J: long class java.util.zip.ZipUtils.CENSIZ(byte[], int) != long java.util.zip.ZipUtils.CENSIZ(byte[], int)
FAILED: Ljava/util/regex/Pattern$BmpCharProperty;match(Ljava/util/regex/Matcher;ILjava/lang/CharSequence;)Z: bool class java.util.regex.Pattern$BmpCharProperty.match(class java.util.regex.Matcher., int, class java.lang., charhar, shortequence) != boolean java.util.regex.Pattern$BmpCharProperty.match(java.util.regex.Matcher, int, java.lang.CharSequence)
FAILED: Ljava/lang/AbstractStringBuilder;appendChars(Ljava/lang/String;II)V: void class java.lang.AbstractStringBuilder.appendChars(class java.lang., shorttring., int, int) != void java.lang.AbstractStringBuilder.appendChars(java.lang.String, int, int)
FAILED: Ljava/lang/Object;<init>()V: void class java.lang.Object<init>() != void java.lang.Object<init>()
test child finished with -1
---- end ----
Demangle Java: FAILED!
$
After applying this patch:
$ perf test java
65: Demangle Java : Ok
$
Signed-off-by: Nick Gasson <nick.gasson@arm.com>
Reviewed-by: Ian Rogers <irogers@google.com>
Tested-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Tested-by: Ian Rogers <irogers@google.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: http://lore.kernel.org/lkml/20200427061520.24905-4-nick.gasson@arm.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Linux kernel
============
There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.
In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``. The formatted documentation can also be read online at:
https://www.kernel.org/doc/html/latest/
There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.
Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.