Hi folks !
I just noticed, as I was digging into (yet another) unrelated llvm
problem with my code, that sparse-llvm fails to compile something that
has a statement such as:
static char *foo = "Foo !\n";
It pukes in output_data(), where we have initializer non-NULL and
initializer->type is EXPR_STRING. So we hit the default: case which is
an assert(0);
Now a trivial "fix" below doesn't quite work:
diff --git a/sparse-llvm.c b/sparse-llvm.c
index 9226a21..f151939 100644
--- a/sparse-llvm.c
+++ b/sparse-llvm.c
@@ -1181,6 +1181,12 @@ static LLVMValueRef output_data(LLVMModuleRef module, struct symbol *sym)
initial_value = output_data(module, sym);
break;
}
+ case EXPR_STRING: {
+ const char *s = initializer->string->data;
+
+ initial_value = LLVMConstString(strdup(s), strlen(s) + 1, true);
+ break;
+ }
default:
assert(0);
}
That has two interesting effects. First, if llvm is compiled with asserts,
it pukes claiming that the initializer is of the wrong type. Now that's
odd because as far as I can tell, the type is an array of i8 ... and it
works if you don't build the asserts in llvm.
Mind you, I had that problem with a different program, which was using
the various "InContext" variants of the various functions rather than
the global context ones... because at one point I was using the global
context for one of the LLVMInt8Type and that made it fail (again worked
fine without asserts).
Looks like the assert internally to LLVM is a pointer comparison of
Type * so it has to resolve to -exactly- the same type object internally,
pretty touchy. Maybe throwing a cast might help.
The second effect however is that the result is not nice:
.../...
@"<noident>" = private global [7 x i8] c"Foo !\0A\00"
@foo = private global i8* @"<noident>"
.../...
I haven't quite manage to coerce it to just have a single @foo = <something>
so it looks like we need to separately define the storage (the string)
and foo as a pointer to it, unless I missed something.
I tried to use the same construct we use in pseudo_to_value() (I factored
it out) but that results in worse output, where it now names the string
(.str<N>) but then creates a <noident> ptr and then assigns that to foo...
LLVM is harder than it seems :-)
Cheers,
Ben.
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