[LLVMdev] Bad permissions for mapped region

Konstantin Olkhovskiy lupus at oxnull.net
Sat Sep 21 23:17:02 PDT 2013

Hi List,

I'm trying to upgrade our llvm-c based compiler from JIT to MCJIT.
While trying to do so I encountered several problems. Looks like C
API does not have proper functions to intialize LLVM with MCJIT.
I ended up wrapping the following functions in my own init routine.


With this set of functions it attempts to JIT something at least.
I run into a segfault, valgrind reports the following:

==27130== Process terminating with default action of signal 11 (SIGSEGV)
==27130==  Bad permissions for mapped region at address 0xEAF02F7
==27130==    at 0xEAF031F:
llvm::RuntimeDyldELF::resolveX86_64Relocation(llvm::SectionEntry const&,
unsigned long, unsigned long, unsigned int, long, unsigned long)
==27130==    by 0xEAF260F:
llvm::RuntimeDyldELF::resolveRelocation(llvm::SectionEntry const&, unsigned
long, unsigned long, unsigned int, long, unsigned long)
==27130==    by 0xEAF258F:
llvm::RuntimeDyldELF::resolveRelocation(llvm::RelocationEntry const&,
unsigned long) (RuntimeDyldELF.cpp:787)
==27130==    by 0xEAE7C67:
64u> const&, unsigned long) (RuntimeDyld.cpp:462)
==27130==    by 0xEAE543C: llvm::RuntimeDyldImpl::resolveRelocations()
==27130==    by 0xEAE8236: llvm::RuntimeDyld::resolveRelocations()
==27130==    by 0xA25EA99: llvm::MCJIT::finalizeObject() (MCJIT.cpp:173)
==27130==    by 0xAB57918: LLVMGetPointerToGlobal
==27130==    by 0x4E4813D: compile_query (ql.c:2286)
==27130==    by 0x4E4836A: tusto_ql_compile (ql.c:2322)
==27130==    by 0x402D19: process_query (ts_util.c:167)
==27130==    by 0x403205: run_shell (ts_util.c:296)

I have source tree checked out at f46e5eadc307beaef6e8dd0602bb4c63ca41fd50.
To create MCJIT i use provided llvm-c apis:

LLVMInitializeMCJITCompilerOptions(&options, sizeof(options));
options.OptLevel = MODULE_OPT_LEVEL; /* 3 of 0 */
options.CodeModel = LLVMCodeModelJITDefault;

if (LLVMCreateMCJITCompilerForModule(&qry->llvm.engine, qry->llvm.mod,
&options, sizeof(options), &error) != 0) {
fprintf(stderr, "%s\n", error);

Then I do the IR building and get the function pointer i need:

iter->run = LLVMGetPointerToGlobal(qry->llvm.engine, func_ref);

Am i doing something wrong?

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