Dumping graphs on the command line

[Doug Simon]

Hi Alex,

Graphs will only be dumped for methods compiled by Graal. Most likely, your example is small enough that it never reaches the top tier compiler. To force a method to be compiled by Graal, you need to either make sure it's hot (e.g., by placing calls to it in a loop with many iterations) or use -XX:CompileOnly[1]. The former is usually a better approach since you'll get a compilation with a more realistic profile. To see what is being compiled by Graal, use either the -XX:+PrintCompilation or -Dgraal.PrintCompilation=true options (the latter shows C1 compilations as well). To restrict compilation only to Graal, use -XX:-TieredCompilation. As you're probably aware, you need -XX:+UseJVMCICompiler in all cases.

-Doug

[1] https://docs.oracle.com/javase/8/docs/technotes/tools/unix/java.html

> On 2 Jun 2017, at 12:45, Alexander Senier <alexander.senier at tu-dresden.de> wrote:
> 
> Hi all,
> 
> I'm looking into Graal to create data flow graphs from Java programs.
> Following the info from the repository I successfully got graphs in IGV
> from the unittests (Linux, version 0.23 from the website):
> 
> $ JAVA_HOME=../../labsjdk1.8.0_121-jvmci-0.26/ ../../mx/mx igv&
> $ PATH=/opt/graalvm-0.23/bin:$PATH
> JAVA_HOME=../../labsjdk1.8.0_121-jvmci-0.26/ ../../mx/mx unittest
> -Dgraal.Dump= -Dgraal.PrintCFG=true BC_aload
> 
> I see the graphs in IGV as well as the CFGPrinter log output.
> Subsequently, I tried to get the same graphs for a custom example:
> 
> $ /opt/graalvm-0.23/bin/javac  DH.java
> $ /opt/graalvm-0.23/bin/java -Dgraal.Dump= -Dgraal.PrintCFG=true
> -XX:+UseJVMCICompiler DH
> 
> While the program is compiled and run, no graphs are generated in IGV
> nor do I see any log files. I see no graal related messages either.
> 
> What is the canonical way to dump graphs from a compilation, preferably
> on the Linux command line?
> 
> Thanks!
> 
> Cheers,
> Alex
> 
> -- 
> Dipl.-Inf. Alexander Senier
> Scientific Assistant
> 
> TU Dresden
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> Institute of System Architecture
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