Hello all,
I’m having trouble getting this analysis to print out it’s graph of aliases. I am processing an example C file into llvm ir, like this:
int main(void) {
int x=1, y=2, z=3;
int *p;
int **p1, *p2;
if (x==z) { //0x100000f40
p=&x;
p1=&p;
x=2;
*p1+=z;
}
}
clang -S -emit-llvm example.c -o example.ll
Then, I am trying to run the Andersen alias analysis on it:
opt -analyze --cfl-anders-aa -aa example.ll
I wrote a new print function for the anders alias analysis, and the print function parameter Module *M and the Result calculated each indicate that there are no aliases. I’m certain I’m missing something, but I don’t know what. To be absolutely clear, a Result is calculated of type:
std::unique_ptr Result;
And CFLAndersAAResult contains member fields:
DenseMap<const Function *, Optional> Cache;
std::forward_list<cflaa::FunctionHandle> Handles;
The DenseMap Cache is empty, and so is Handles.
I can do -print-alias-sets, and that prints something, but I don’t think it’s the result of the Andersen analysis. Because when I do commands with --cfl-anders-aa taken out, I still get the same alias sets.
Can anybody help me get the Andersen alias results?