| Message ID | 1344196054-17208-1-git-send-email-penberg@kernel.org (mailing list archive) |
|---|---|
| State | Mainlined, archived |
| Headers | show |
On Sun, Aug 05, 2012 at 10:47:34PM +0300, Pekka Enberg wrote: > Jonathan Neuschäfer writes: > > compiling a little real-world program with sparse-llvm, it segfaulted. > Using a tool called "delta"[1] and some bash scripting, I managed to > reduce the code to this test case: > > extern struct foo *foop; > extern void func(struct foo *f); > int main(int argc, char **argv) { > func(foop); > } > > The problem is that pseudo_to_value() does not know abou the extern > symbol because Sparse never calls output_data() on it which registers > globals with LLVMAddGlobal(). > > As explained by Linus, 'extern' symbols are just names with types. They > don't have any value associated with them, they just have the type and > the name. Therefore we need to explicitly call LLVMAddGlobal() for > symbols we have not encountered in pseudo_to_value(). > > Reported by: Jonathan Neuschäfer <j.neuschaefer@gmx.net> > Cc: Christopher Li <sparse@chrisli.org> > Cc: Jeff Garzik <jgarzik@redhat.com> > Cc: Linus Torvalds <torvalds@linux-foundation.org> > Signed-off-by: Pekka Enberg <penberg@kernel.org> This fixes the crash, thanks. Jonathan -- To unsubscribe from this list: send the line "unsubscribe linux-sparse" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
diff --git a/sparse-llvm.c b/sparse-llvm.c index 6b94205..5bcc758 100644 --- a/sparse-llvm.c +++ b/sparse-llvm.c @@ -335,6 +335,14 @@ static LLVMValueRef pseudo_to_value(struct function *fn, struct instruction *ins default: assert(0); } + } else { + const char *name = show_ident(sym->ident); + + result = LLVMGetNamedGlobal(fn->module, name); + if (!result) { + LLVMTypeRef type = symbol_type(fn->module, sym); + result = LLVMAddGlobal(fn->module, type, name); + } } break; } diff --git a/validation/backend/extern.c b/validation/backend/extern.c new file mode 100644 index 0000000..24cbae5 --- /dev/null +++ b/validation/backend/extern.c @@ -0,0 +1,11 @@ +extern unsigned long foo; + +static unsigned long bar(void) +{ + return foo; +} + +/* + * check-name: Extern symbol code generation + * check-command: ./sparsec -c $file -o tmp.o + */
Jonathan Neuschäfer writes: compiling a little real-world program with sparse-llvm, it segfaulted. Using a tool called "delta"[1] and some bash scripting, I managed to reduce the code to this test case: extern struct foo *foop; extern void func(struct foo *f); int main(int argc, char **argv) { func(foop); } The problem is that pseudo_to_value() does not know abou the extern symbol because Sparse never calls output_data() on it which registers globals with LLVMAddGlobal(). As explained by Linus, 'extern' symbols are just names with types. They don't have any value associated with them, they just have the type and the name. Therefore we need to explicitly call LLVMAddGlobal() for symbols we have not encountered in pseudo_to_value(). Reported by: Jonathan Neuschäfer <j.neuschaefer@gmx.net> Cc: Christopher Li <sparse@chrisli.org> Cc: Jeff Garzik <jgarzik@redhat.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Pekka Enberg <penberg@kernel.org> --- sparse-llvm.c | 8 ++++++++ validation/backend/extern.c | 11 +++++++++++ 2 files changed, 19 insertions(+), 0 deletions(-) create mode 100644 validation/backend/extern.c