| Message ID | 20170816153455.97693-12-luc.vanoostenryck@gmail.com (mailing list archive) |
|---|---|
| State | Changes Requested, archived |
| Headers | show |
On Wed, Aug 16, 2017 at 11:34 AM, Luc Van Oostenryck <luc.vanoostenryck@gmail.com> wrote: > Processing in the middle-end are much easier if undefined values > have been clearly identified. Once done, we can then make > choices like: > - always initialize them to zero > - allow arbitraly simplification, Can pick arbitrate initialized value, but can't do arbitraly simplification. The chance looks good. I need to take a crash now. To be continue... Chris -- 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
Hi Chris, On 17 August 2017 at 08:30, Christopher Li <sparse@chrisli.org> wrote: > On Wed, Aug 16, 2017 at 11:34 AM, Luc Van Oostenryck > <luc.vanoostenryck@gmail.com> wrote: >> Processing in the middle-end are much easier if undefined values >> have been clearly identified. Once done, we can then make >> choices like: >> - always initialize them to zero >> - allow arbitraly simplification, > > Can pick arbitrate initialized value, but can't do arbitraly simplification. > I agree with that. Perhaps a specific default value can be set? Regards Dibyendu -- 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
On Thu, Aug 17, 2017 at 6:55 PM, Dibyendu Majumdar <mobile@majumdar.org.uk> wrote: >>> Processing in the middle-end are much easier if undefined values >>> have been clearly identified. Once done, we can then make >>> choices like: >>> - always initialize them to zero >>> - allow arbitraly simplification, >> >> Can pick arbitrate initialized value, but can't do arbitraly simplification. >> > > I agree with that. Perhaps a specific default value can be set? I was speaking loosely to say that a lot of simplifications are possible once the involved pseudo(s) is/are undefined. -- Luc -- 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/linearize.c b/linearize.c index 190c47241..9ec65079a 100644 --- a/linearize.c +++ b/linearize.c @@ -155,6 +155,8 @@ const char *show_pseudo(pseudo_t pseudo) if (pseudo->ident) sprintf(buf+i, "(%s)", show_ident(pseudo->ident)); break; + case PSEUDO_UNDEF: + return "UNDEF"; default: snprintf(buf, 64, "<bad pseudo type %d>", pseudo->type); } diff --git a/linearize.h b/linearize.h index c03940eea..54fcf2a46 100644 --- a/linearize.h +++ b/linearize.h @@ -21,6 +21,7 @@ DECLARE_PTR_LIST(pseudo_user_list, struct pseudo_user); enum pseudo_type { PSEUDO_VOID, + PSEUDO_UNDEF, PSEUDO_REG, PSEUDO_SYM, PSEUDO_VAL, @@ -290,7 +291,7 @@ static inline void add_pseudo_user_ptr(struct pseudo_user *user, struct pseudo_u static inline int has_use_list(pseudo_t p) { - return (p && p->type != PSEUDO_VOID && p->type != PSEUDO_VAL); + return (p && p->type != PSEUDO_VOID && p->type != PSEUDO_UNDEF && p->type != PSEUDO_VAL); } static inline struct pseudo_user *alloc_pseudo_user(struct instruction *insn, pseudo_t *pp) diff --git a/sparse-llvm.c b/sparse-llvm.c index 29fb65f15..f8d48d264 100644 --- a/sparse-llvm.c +++ b/sparse-llvm.c @@ -289,6 +289,7 @@ static void pseudo_name(pseudo_t pseudo, char *buf) assert(0); break; case PSEUDO_VAL: + case PSEUDO_UNDEF: assert(0); break; case PSEUDO_ARG: { @@ -372,6 +373,9 @@ static LLVMValueRef pseudo_to_value(struct function *fn, struct instruction *ins case PSEUDO_VOID: result = NULL; break; + case PSEUDO_UNDEF: + result = LLVMGetUndef(symbol_type(fn->module, insn->type)); + break; default: assert(0); }
Processing in the middle-end are much easier if undefined values have been clearly identified. Once done, we can then make choices like: - always initialize them to zero - allow arbitraly simplification, - ... Prepare for this by declaring a new type of pseudo: PSEUDO_UNDEF somewhat similar to PSEUDO_VOID. Signed-off-by: Luc Van Oostenryck <luc.vanoostenryck@gmail.com> --- linearize.c | 2 ++ linearize.h | 3 ++- sparse-llvm.c | 4 ++++ 3 files changed, 8 insertions(+), 1 deletion(-)