Hi,
The call target pass in the poolalloc suite yields an incorrect output for the
following short test program:
#include <stdio.h>
struct OP {
void (*func)(struct OP*);
};
void bar(struct OP *op);
void foo(struct OP *op) {
printf("Foo\n");
op->func = bar;
}
void bar(struct OP *op) {
printf("Bar\n");
op->func = foo;
}
int main(int argc, char **argv) {
int i;
struct OP op;
op.func = foo;
for(i = 0; i < 10; ++i) {
op.func(&op);
}
return 0;
}
Specifically, pass indicates that indirect function call in the main function
may call the foo method and that the the list of callees is complete. In fact,
the indirect function call can target both the foo and bar methods, so the list
should be marked incomplete, or should include the other callees. Thanks.
Tom
On Thu, Sep 25, 2008 at 5:04 PM, Thomas B. Jablin <tjablin at cs.princeton.edu> wrote:> Hi, > The call target pass in the poolalloc suite yields an incorrect output for the following short test program:The DSA results are now (r56847) correct for this test case. The call is marked incomplete. Doing better is actually a pathological case in DSA which is hard to fix without expotential growth problems, but I have some ideas (and happen to have to be working on DSA for something anyway, so you are in luck). Andrew> #include <stdio.h> > > struct OP { > void (*func)(struct OP*); > }; > > void bar(struct OP *op); > > void foo(struct OP *op) { > printf("Foo\n"); > op->func = bar; > } > > void bar(struct OP *op) { > printf("Bar\n"); > op->func = foo; > } > > int main(int argc, char **argv) { > int i; > struct OP op; > op.func = foo; > for(i = 0; i < 10; ++i) { > op.func(&op); > } > return 0; > } > > Specifically, pass indicates that indirect function call in the main function may call the foo method and that the the list of callees is complete. In fact, the indirect function call can target both the foo and bar methods, so the list should be marked incomplete, or should include the other callees. Thanks. > Tom > _______________________________________________ > LLVM Developers mailing list > LLVMdev at cs.uiuc.edu http://llvm.cs.uiuc.edu > http://lists.cs.uiuc.edu/mailman/listinfo/llvmdev >
Thanks. ----- Original Message ----- From: "Andrew Lenharth" <andrewl at lenharth.org> To: "LLVM Developers Mailing List" <llvmdev at cs.uiuc.edu> Sent: Tuesday, September 30, 2008 11:31:26 AM GMT -05:00 US/Canada Eastern Subject: Re: [LLVMdev] CallTargets Analysis Incorrect On Thu, Sep 25, 2008 at 5:04 PM, Thomas B. Jablin <tjablin at cs.princeton.edu> wrote:> Hi, > The call target pass in the poolalloc suite yields an incorrect output for the following short test program:The DSA results are now (r56847) correct for this test case. The call is marked incomplete. Doing better is actually a pathological case in DSA which is hard to fix without expotential growth problems, but I have some ideas (and happen to have to be working on DSA for something anyway, so you are in luck). Andrew> #include <stdio.h> > > struct OP { > void (*func)(struct OP*); > }; > > void bar(struct OP *op); > > void foo(struct OP *op) { > printf("Foo\n"); > op->func = bar; > } > > void bar(struct OP *op) { > printf("Bar\n"); > op->func = foo; > } > > int main(int argc, char **argv) { > int i; > struct OP op; > op.func = foo; > for(i = 0; i < 10; ++i) { > op.func(&op); > } > return 0; > } > > Specifically, pass indicates that indirect function call in the main function may call the foo method and that the the list of callees is complete. In fact, the indirect function call can target both the foo and bar methods, so the list should be marked incomplete, or should include the other callees. Thanks. > Tom > _______________________________________________ > LLVM Developers mailing list > LLVMdev at cs.uiuc.edu http://llvm.cs.uiuc.edu > http://lists.cs.uiuc.edu/mailman/listinfo/llvmdev >_______________________________________________ LLVM Developers mailing list LLVMdev at cs.uiuc.edu http://llvm.cs.uiuc.edu http://lists.cs.uiuc.edu/mailman/listinfo/llvmdev