"Jumped to invalid address in trampoline"

[Erhannis]

I've finally gotten nestedvm to compile (I'd add MAKEINFO=true to the make dist ... arguments, in the README), but I have yet to successfully run a translated class. For instance, I have a test cc.c in /tmp/:

#include <stdio.h>

int test(int x) {
    return x*4;
}

int main(int argc, char **argv) {
    printf("hello moon!\n");
    return test(1717);
}

And in upstream/install/bin/ I run

./mips-unknown-elf-gcc -o /tmp/cc /tmp/cc.c

and get

/home/erhannis/Documents/workspace/nestedvm/install/bin/../lib/gcc/mips-unknown-elf/4.8.5/../../../../mips-unknown-elf/bin/ld: warning: cannot find entry symbol _start; defaulting to 0000000000010000

but it seeeems to work. So I run either

java -jar nestedvm.jar /tmp/cc

or

java -jar compiler.jar -outfile /tmp/cc.class cc /tmp/cc
java -cp /tmp/:unix_runtime.jar cc

and in either case I get similar errors

org.ibex.nestedvm.Runtime$ExecutionException: Jumped to invalid address in trampoline (r2: -1 pc: -559038737) at (unknown)
	at cc.trampoline(/tmp/cc)
	at cc._execute(/tmp/cc)
	at org.ibex.nestedvm.Runtime.__execute(Runtime.java:511)
	at org.ibex.nestedvm.Runtime.execute(Runtime.java:528)
	at org.ibex.nestedvm.Runtime.run(Runtime.java:550)
	at org.ibex.nestedvm.Runtime.run(Runtime.java:543)
	at org.ibex.nestedvm.Runtime.run(Runtime.java:542)
	at cc.main(/tmp/cc)
Process exited on signal 4

or

Instansiated: nestedvm.runtimecompiled@156643d4
org.ibex.nestedvm.Runtime$ExecutionException: Jumped to invalid address in trampoline (r2: -1 pc: -559038737) at (unknown)
	at nestedvm.runtimecompiled.trampoline(Unknown Source)
	at nestedvm.runtimecompiled._execute(Unknown Source)
	at org.ibex.nestedvm.Runtime.__execute(Runtime.java:511)
	at org.ibex.nestedvm.Runtime.execute(Runtime.java:528)
	at org.ibex.nestedvm.UnixRuntime.executeAndExec(UnixRuntime.java:501)
	at org.ibex.nestedvm.UnixRuntime.runAndExec(UnixRuntime.java:495)
	at org.ibex.nestedvm.RuntimeCompiler.main(RuntimeCompiler.java:69)
Process exited on signal 4

Any idea what's up?
(I'd also gotten similar results with an effectively-empty main method, but this was the code I'd most recently tested, anyway.)

[Erhannis]

Oh - it should be noted perhaps that I installed openjdk-8-jdk rather than openjdk-7-jdk, because that's what was available. Would that cause this, do you think?

[zacura]

@Erhannis Initially I got the same errors, but reading the Makefile pointed me into the correct command line for using nestedvm. Here is how I got my Hello World (test.c) compiled to a Java class (output to build/com/test directory):

Compile C source

mips-unknown-elf-gcc -O3 -mmemcpy -ffunction-sections -fdata-sections -falign-functions=512 -fno-rename-registers -fno-schedule-insns -fno-delayed-branch -march=mips1 -specs=/usr/local/nestedvm/mips-unknown-elf/lib/crt0-override.spec -I. -Wall -Wno-unused -c -o build/com/test/Test.o test.c

Link to a MIPS binary

mips-unknown-elf-gcc -o build/com/test/Test.mips build/com/test/Test.o -march=mips1 -specs=/usr/local/nestedvm/mips-unknown-elf/lib/crt0-override.spec --static -Wl,--gc-sections

Compile to a Java class

java -cp "/usr/local/nestedvm/share/java/nestedvm-compiler.jar:build" org.ibex.nestedvm.Compiler -outformat class -d build com.test.Test build/com/test/Test.mips

Running the resulting Java application

java -cp /usr/local/nestedvm/share/java/nestedvm-runtime.jar:build com.test.Test

[Erhannis]

Holy COW. You'd think something like that would be in the README. It works, though! Good find. I'll update the README and make a pull request, in case @bgould ever sees it, I guess, haha.

[Erhannis]

Pull request: #4