On Tue, Sep 16, 2014 at 5:12 PM, Eric Christopher <[email protected]> wrote:
> > > On Tue, Sep 16, 2014 at 4:00 PM, Akira Hatanaka <[email protected]> > wrote: > >> On Tue, Sep 16, 2014 at 1:06 PM, Eric Christopher <[email protected]> >> wrote: >> >>> You'll want to split out the new contraints for input size into a >>> separate patch. (And just commit it). >>> A small comment of why we're ignoring dependent types would be good. >>> >>> One question: Why not just add all of the contraints first rather than >>> piecemeal as you get testcases? (Related to the comment above). >>> >>> >> Just to make sure I'm not misunderstanding your question, are you >> suggesting I use "=abcdSD" instead of "=a" in the test case and do the >> check in one line? >> >> uint64_t val; >> >> __asm__ volatile("addl %1, %0" : "=abcdSD" (val) : "a" (msr)); // >> expected-error {{invalid output size for constraint '=abcdSD'}} >> >> >> Are you also suggesting that we should have clang print just the >> constraints that are invalid in the error message? For example, if we added >> "A" and use "=abcdSDA" instead, clang would remove "A", since it can be >> bound to a 64-bit variable, and print "=abcdSD" or "abcdSD" instead? >> >> >> > No, I'm curious why you're adding S and D now, but not any other > constraint that has a size associated with the register. > > OK, I see. I just felt that S and D should be added too, since they are single register constraints that have to be bound to variables smaller than 64-bit, as constraints a-d are. I can probably add R, q, Q, to the switch-case statement too. Also, in my next patch, I was going to add checks for constraints x and y. Should I add the all the constraints I mentioned above to X86_32TargetInfo::validateInputSize or X86TargetInfo::validateInputSize first and then add the checks for output constraints? -eric > > >> >> Thanks! >>> >>> -eric >>> >>> On Fri Aug 29 2014 at 4:46:37 PM Akira Hatanaka <[email protected]> >>> wrote: >>> >>>> Does the latest patch look fine? I am working on another patch which >>>> fixes a similar bug and I need to commit this patch first. >>>> >>>> >>>> On Thu, Aug 28, 2014 at 10:08 AM, Akira Hatanaka <[email protected]> >>>> wrote: >>>> >>>>> Latest version of the patch is attached which fixes a couple of >>>>> oversights. I had to add a line which checks whether Ty is a dependent >>>>> type >>>>> before getTypeSize is called. Also, in the test case, "=" was missing >>>>> before constraint "a", so fixed that too. >>>>> >>>>> On Wed, Aug 27, 2014 at 3:22 PM, Reid Kleckner <[email protected]> wrote: >>>>> >>>>>> New patch looks good to me. >>>>>> >>>>>> It sounds like we have two cases of size mismatch: >>>>>> - The output operand lvalue is smaller than the constraint, meaning >>>>>> the store will write out of bounds. Your patch adds this. >>>>>> - The output operand lvalue is bigger than the constraint, meaning >>>>>> the whole value won't be initialized. We currently warn here via >>>>>> validateConstraintModifier. >>>>>> >>>>>> This code probably deserves some cleanup, but your patch is >>>>>> consistent with what we do for input operands, so let's go with that. >>>>>> >>>>>> >>>>> The reason llvm is crashing in the backend is that it's trying to use >>>>> a 64-bit register in 32-bit mode. It's not because a store is writing out >>>>> of bounds or there is a value left uninitialized. In the test case, if we >>>>> declare the variable bound to constraint "=a" to be a unit32_t or an >>>>> integer type that is smaller than 32-bit, clang compiles the program fine. >>>>> >>>>> >>>>>> >>>>>> On Wed, Aug 27, 2014 at 12:35 PM, Akira Hatanaka <[email protected]> >>>>>> wrote: >>>>>> >>>>>>> The commit log in r166737 doesn't say much about why this is a >>>>>>> warning instead of an error, but I know there are cases where warnings >>>>>>> are >>>>>>> needed. For example, clang has to issue warnings instead of errors for >>>>>>> the >>>>>>> inline-asm statements in the test case committed in r216260. If it's not >>>>>>> desirable to change validateConstraintModifier, we can add a function >>>>>>> which >>>>>>> checks the output size that is similar to validateInputSize in r167717 >>>>>>> (see >>>>>>> attached patch), which was suggested in the post-commit review. >>>>>>> >>>>>>> >>>>>>> http://lists.cs.uiuc.edu/pipermail/cfe-commits/Week-of-Mon-20121112/067945.html >>>>>>> >>>>>>> I am not sure whether we can use fixit in this case. Fixit hints >>>>>>> should be used only if we know the user's intent and it's very clear >>>>>>> that >>>>>>> applying the fixit hint is the right thing to do. Changing the type of >>>>>>> variable "r" to a 32-bit int will avoid crashing, but it doesn't look >>>>>>> like >>>>>>> that's what the user wants. >>>>>>> >>>>>>> On Mon, Aug 25, 2014 at 6:20 PM, Reid Kleckner <[email protected]> >>>>>>> wrote: >>>>>>> >>>>>>>> Can you investigate why we are warning in the first place? I think >>>>>>>> we should either only warn or only error. Currently we have a warning >>>>>>>> with >>>>>>>> a fixit but we don't recover as though we had applied the fixit. If we >>>>>>>> did >>>>>>>> that, we would not crash. >>>>>>>> >>>>>>>> In addition to the Clang-side changes, LLVM should probably be >>>>>>>> returning an error or reporting a fatal error instead of hitting >>>>>>>> unreachable. >>>>>>>> >>>>>>>> >>>>>>>> On Mon, Aug 25, 2014 at 2:10 PM, Akira Hatanaka < >>>>>>>> [email protected]> wrote: >>>>>>>> >>>>>>>>> Rebased patches attached. >>>>>>>>> >>>>>>>>> I also made changes to the clang patch so that clang can error-out >>>>>>>>> after a size mismatch is found as soon as >>>>>>>>> possible.TargetInfo::validateConstraintModifier has an extra parameter >>>>>>>>> IsError, which is set when it decides there is no point in continuing >>>>>>>>> compilation and it should stop compilation immediately. The error >>>>>>>>> message >>>>>>>>> clang prints looks better than lllvm's message, but if it isn't right >>>>>>>>> to >>>>>>>>> change the warning to an error, then I guess we have to detect the >>>>>>>>> error >>>>>>>>> later just before isel, as is done in the llvm patch. >>>>>>>>> >>>>>>>>> On Wed, Jul 23, 2014 at 3:56 PM, Akira Hatanaka < >>>>>>>>> [email protected]> wrote: >>>>>>>>> >>>>>>>>>> llvm should error-out when a 64-bit variable is bound to a single >>>>>>>>>> register in x86 32-bit mode, but ToT clang/llvm fails to detect this >>>>>>>>>> error >>>>>>>>>> and continues compilation until it crashes in type-legalization: >>>>>>>>>> >>>>>>>>>> $ llc test/CodeGen/X86/inline-asm-regsize.ll -O3 >>>>>>>>>> -mtriple=i386-apple-darwin -o - >>>>>>>>>> >>>>>>>>>> inline-asm-regsize.ll -O3 -mtriple=i386-apple-darwin -o - >>>>>>>>>> >>>>>>>>>> .section __TEXT,__text,regular,pure_instructions >>>>>>>>>> >>>>>>>>>> ExpandIntegerResult #0: 0x7fa2d1041728: i64 = Register %RCX [ID=0] >>>>>>>>>> >>>>>>>>>> >>>>>>>>>> Do not know how to expand the result of this operator! >>>>>>>>>> >>>>>>>>>> UNREACHABLE executed at >>>>>>>>>> /Users/ahatanaka/projects/llvm/git/llvm3/lib/CodeGen/SelectionDAG/LegalizeIntegerTypes.cpp:1116! >>>>>>>>>> >>>>>>>>>> The attached patch fixes llvm to error-out and print this error >>>>>>>>>> message: >>>>>>>>>> >>>>>>>>>> error: Cannot bind a variable larger than 32-bit to a single >>>>>>>>>> register in 32-bit mode >>>>>>>>>> >>>>>>>>>> >>>>>>>>>> My initial solution was to have clang detect this error in >>>>>>>>>> TargetInfo::validateConstraintModifier. However, the code in >>>>>>>>>> SemaStmtAsm.cpp has to be changed to error-out instead of issuing a >>>>>>>>>> warning, which I wasn't sure was the right thing to do. I am >>>>>>>>>> attaching this >>>>>>>>>> patch too in case someone has a suggestion or an opinion on it. >>>>>>>>>> >>>>>>>>>> <rdar://problem/17476970> >>>>>>>>>> >>>>>>>>>> >>>>>>>>> >>>>>>>>> _______________________________________________ >>>>>>>>> cfe-commits mailing list >>>>>>>>> [email protected] >>>>>>>>> http://lists.cs.uiuc.edu/mailman/listinfo/cfe-commits >>>>>>>>> >>>>>>>>> >>>>>>>> >>>>>>> >>>>>> >>>>> >>>>> >>>>> >>>> _______________________________________________ >>>> cfe-commits mailing list >>>> [email protected] >>>> http://lists.cs.uiuc.edu/mailman/listinfo/cfe-commits >>>> >>> >> >
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