[llvm] r373333 - [InstCombine] sprintf(dest, "%s", str) -> memccpy(dest, str, 0, MAX)

Wed Oct 2 06:42:48 PDT 2019

Looks like this has already been reverted in r373335. My apologies, false alarm.

Peter

On Wed, 2 Oct 2019 at 14:25, Peter Smith <peter.smith at linaro.org> wrote:
>
> This change has caused a regression in the AArch64 Linux kernel build
> (Linaro CI), I'll forward the details from the CI system of how to
> reproduce it directly via email
>
> The errors look to be from the linux kernel module tool modpost. These
> are undefined symbols coming from linux kernel modules.
> ERROR: "memccpy" [sound/pci/hda/snd-hda-codec-ca0132.ko] undefined!
> ERROR: "memccpy" [drivers/infiniband/hw/mlx4/mlx4_ib.ko] undefined!
> ERROR: "memccpy" [drivers/target/iscsi/iscsi_target_mod.ko] undefined!
> ERROR: "memccpy" [drivers/nvdimm/libnvdimm.ko] undefined!
> ERROR: "memccpy" [drivers/staging/rtl8192e/rtllib.ko] undefined!
> ERROR: "memccpy" [drivers/i2c/busses/i2c-jz4780.ko] undefined!
> ERROR: "memccpy" [drivers/usb/mtu3/mtu3.ko] undefined!
> ERROR: "memccpy" [drivers/net/usb/hso.ko] undefined!
> ERROR: "memccpy" [drivers/net/wireless/ath/ath9k/ath9k_htc.ko] undefined!
> ERROR: "memccpy" [drivers/net/ethernet/apm/xgene-v2/xgene-enet-v2.ko] undefined!
> ERROR: "memccpy" [drivers/net/ethernet/apm/xgene/xgene-enet.ko] undefined!
> ERROR: "memccpy" [drivers/net/ethernet/qlogic/qed/qed.ko] undefined!
> ERROR: "memccpy" [drivers/net/ethernet/mellanox/mlx4/mlx4_core.ko] undefined!
> ERROR: "memccpy" [drivers/net/ethernet/cavium/liquidio/liquidio_vf.ko]
> undefined!
> ERROR: "memccpy" [drivers/net/ethernet/cavium/liquidio/liquidio.ko] undefined!
> ERROR: "memccpy" [drivers/net/ethernet/brocade/bna/bna.ko] undefined!
> ERROR: "memccpy" [drivers/scsi/mpt3sas/mpt3sas.ko] undefined!
> ERROR: "memccpy" [drivers/scsi/bfa/bfa.ko] undefined!
>
> I believe that memccpy is not in the C Standard so it is likely the
> Linux kernel does not provide its own definition. Is there a reason to
> use a non-standard memccpy in the transformation unless we can
> guarantee that the environment will support it?
>
> Can you take a look?
>
> Peter
>
> On Tue, 1 Oct 2019 at 14:01, David Bolvansky via llvm-commits
> <llvm-commits at lists.llvm.org> wrote:
> >
> > Author: xbolva00
> > Date: Tue Oct  1 06:03:10 2019
> > New Revision: 373333
> >
> > URL: http://llvm.org/viewvc/llvm-project?rev=373333&view=rev
> > Log:
> > [InstCombine] sprintf(dest, "%s", str) -> memccpy(dest, str, 0, MAX)
> >
> > Modified:
> >     llvm/trunk/lib/Transforms/Utils/SimplifyLibCalls.cpp
> >     llvm/trunk/test/Transforms/InstCombine/2010-05-30-memcpy-Struct.ll
> >     llvm/trunk/test/Transforms/InstCombine/sprintf-1.ll
> >
> > Modified: llvm/trunk/lib/Transforms/Utils/SimplifyLibCalls.cpp
> > URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Transforms/Utils/SimplifyLibCalls.cpp?rev=373333&r1=373332&r2=373333&view=diff
> > ==============================================================================
> > --- llvm/trunk/lib/Transforms/Utils/SimplifyLibCalls.cpp (original)
> > +++ llvm/trunk/lib/Transforms/Utils/SimplifyLibCalls.cpp Tue Oct  1 06:03:10 2019
> > @@ -2415,9 +2415,11 @@ Value *LibCallSimplifier::optimizePrintF
> >  }
> >
> >  Value *LibCallSimplifier::optimizeSPrintFString(CallInst *CI, IRBuilder<> &B) {
> > +  Value *Dst = CI->getArgOperand(0);
> > +  Value *FmtStr = CI->getArgOperand(1);
> >    // Check for a fixed format string.
> >    StringRef FormatStr;
> > -  if (!getConstantStringInfo(CI->getArgOperand(1), FormatStr))
> > +  if (!getConstantStringInfo(FmtStr, FormatStr))
> >      return nullptr;
> >
> >    // If we just have a format string (nothing else crazy) transform it.
> > @@ -2428,9 +2430,10 @@ Value *LibCallSimplifier::optimizeSPrint
> >        return nullptr; // we found a format specifier, bail out.
> >
> >      // sprintf(str, fmt) -> llvm.memcpy(align 1 str, align 1 fmt, strlen(fmt)+1)
> > -    B.CreateMemCpy(CI->getArgOperand(0), 1, CI->getArgOperand(1), 1,
> > -                   ConstantInt::get(DL.getIntPtrType(CI->getContext()),
> > -                                    FormatStr.size() + 1)); // Copy the null byte.
> > +    B.CreateMemCpy(
> > +        Dst, 1, FmtStr, 1,
> > +        ConstantInt::get(DL.getIntPtrType(CI->getContext()),
> > +                         FormatStr.size() + 1)); // Copy the null byte.
> >      return ConstantInt::get(CI->getType(), FormatStr.size());
> >    }
> >
> > @@ -2440,13 +2443,14 @@ Value *LibCallSimplifier::optimizeSPrint
> >        CI->getNumArgOperands() < 3)
> >      return nullptr;
> >
> > +  Value *Str = CI->getArgOperand(2);
> >    // Decode the second character of the format string.
> >    if (FormatStr[1] == 'c') {
> >      // sprintf(dst, "%c", chr) --> *(i8*)dst = chr; *((i8*)dst+1) = 0
> > -    if (!CI->getArgOperand(2)->getType()->isIntegerTy())
> > +    if (!Str->getType()->isIntegerTy())
> >        return nullptr;
> > -    Value *V = B.CreateTrunc(CI->getArgOperand(2), B.getInt8Ty(), "char");
> > -    Value *Ptr = castToCStr(CI->getArgOperand(0), B);
> > +    Value *V = B.CreateTrunc(Str, B.getInt8Ty(), "char");
> > +    Value *Ptr = castToCStr(Dst, B);
> >      B.CreateStore(V, Ptr);
> >      Ptr = B.CreateGEP(B.getInt8Ty(), Ptr, B.getInt32(1), "nul");
> >      B.CreateStore(B.getInt8(0), Ptr);
> > @@ -2455,17 +2459,30 @@ Value *LibCallSimplifier::optimizeSPrint
> >    }
> >
> >    if (FormatStr[1] == 's') {
> > -    // sprintf(dest, "%s", str) -> llvm.memcpy(align 1 dest, align 1 str,
> > -    // strlen(str)+1)
> > -    if (!CI->getArgOperand(2)->getType()->isPointerTy())
> > +    if (!Str->getType()->isPointerTy())
> >        return nullptr;
> > +
> > +    // sprintf(dest, "%s", str) -> memccpy(dest, str, 0, MAX)
> > +    if (CI->use_empty()) {
> > +      Value *S = (Dst->getType() == Str->getType())
> > +                     ? Str
> > +                     : B.CreateBitCast(Str, Dst->getType());
> > +      unsigned SizeTyBitwidth =
> > +          DL.getIntPtrType(CI->getContext())->getPrimitiveSizeInBits();
> > +      Value *NewSize = ConstantInt::get(B.getIntNTy(SizeTyBitwidth),
> > +                                        APInt::getMaxValue(SizeTyBitwidth));
> > +      emitMemCCpy(Dst, S, B.getInt32('\0'), NewSize, B, TLI);
> > +      return Dst;
> > +    }
> >
> > -    Value *Len = emitStrLen(CI->getArgOperand(2), B, DL, TLI);
> > +    // sprintf(dest, "%s", str) -> llvm.memcpy(align 1 dest, align 1 str,
> > +    // strlen(str)+1)
> > +    Value *Len = emitStrLen(Str, B, DL, TLI);
> >      if (!Len)
> >        return nullptr;
> >      Value *IncLen =
> >          B.CreateAdd(Len, ConstantInt::get(Len->getType(), 1), "leninc");
> > -    B.CreateMemCpy(CI->getArgOperand(0), 1, CI->getArgOperand(2), 1, IncLen);
> > +    B.CreateMemCpy(Dst, 1, Str, 1, IncLen);
> >
> >      // The sprintf result is the unincremented number of bytes in the string.
> >      return B.CreateIntCast(Len, CI->getType(), false);
> >
> > Modified: llvm/trunk/test/Transforms/InstCombine/2010-05-30-memcpy-Struct.ll
> > URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/Transforms/InstCombine/2010-05-30-memcpy-Struct.ll?rev=373333&r1=373332&r2=373333&view=diff
> > ==============================================================================
> > --- llvm/trunk/test/Transforms/InstCombine/2010-05-30-memcpy-Struct.ll (original)
> > +++ llvm/trunk/test/Transforms/InstCombine/2010-05-30-memcpy-Struct.ll Tue Oct  1 06:03:10 2019
> > @@ -1,3 +1,4 @@
> > +; NOTE: Assertions have been autogenerated by utils/update_test_checks.py
> >  ; RUN: opt -instcombine -S < %s | FileCheck %s
> >  ; PR7265
> >
> > @@ -9,10 +10,14 @@ target triple = "x86_64-unknown-linux-gn
> >  @.str = private constant [3 x i8] c"%s\00"
> >
> >  define void @CopyEventArg(%union.anon* %ev) nounwind {
> > +; CHECK-LABEL: @CopyEventArg(
> > +; CHECK-NEXT:  entry:
> > +; CHECK-NEXT:    [[TMP0:%.*]] = bitcast %union.anon* [[EV:%.*]] to i8*
> > +; CHECK-NEXT:    [[MEMCCPY:%.*]] = call i8* @memccpy(i8* undef, i8* [[TMP0]], i32 0, i64 -1)
> > +; CHECK-NEXT:    ret void
> > +;
> >  entry:
> >    %call = call i32 (i8*, i8*, ...) @sprintf(i8* undef, i8* getelementptr inbounds ([3 x i8], [3 x i8]* @.str, i64 0, i64 0), %union.anon* %ev) nounwind
> > -; CHECK: bitcast %union.anon* %ev to i8*
> > -; CHECK: call void @llvm.memcpy.p0i8.p0i8.i64
> >    ret void
> >  }
> >
> >
> > Modified: llvm/trunk/test/Transforms/InstCombine/sprintf-1.ll
> > URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/Transforms/InstCombine/sprintf-1.ll?rev=373333&r1=373332&r2=373333&view=diff
> > ==============================================================================
> > --- llvm/trunk/test/Transforms/InstCombine/sprintf-1.ll (original)
> > +++ llvm/trunk/test/Transforms/InstCombine/sprintf-1.ll Tue Oct  1 06:03:10 2019
> > @@ -85,15 +85,11 @@ define void @test_simplify4(i8* %dst) {
> >
> >  define void @test_simplify5(i8* %dst, i8* %str) {
> >  ; CHECK-LABEL: @test_simplify5(
> > -; CHECK-NEXT:    [[STRLEN:%.*]] = call i32 @strlen(i8* nonnull dereferenceable(1) [[STR:%.*]])
> > -; CHECK-NEXT:    [[LENINC:%.*]] = add i32 [[STRLEN]], 1
> > -; CHECK-NEXT:    call void @llvm.memcpy.p0i8.p0i8.i32(i8* align 1 [[DST:%.*]], i8* align 1 [[STR]], i32 [[LENINC]], i1 false)
> > +; CHECK-NEXT:    [[MEMCCPY:%.*]] = call i8* @memccpy(i8* [[DST:%.*]], i8* [[STR:%.*]], i32 0, i32 -1)
> >  ; CHECK-NEXT:    ret void
> >  ;
> >  ; CHECK-IPRINTF-LABEL: @test_simplify5(
> > -; CHECK-IPRINTF-NEXT:    [[STRLEN:%.*]] = call i32 @strlen(i8* nonnull dereferenceable(1) [[STR:%.*]])
> > -; CHECK-IPRINTF-NEXT:    [[LENINC:%.*]] = add i32 [[STRLEN]], 1
> > -; CHECK-IPRINTF-NEXT:    call void @llvm.memcpy.p0i8.p0i8.i32(i8* align 1 [[DST:%.*]], i8* align 1 [[STR]], i32 [[LENINC]], i1 false)
> > +; CHECK-IPRINTF-NEXT:    [[MEMCCPY:%.*]] = call i8* @memccpy(i8* [[DST:%.*]], i8* [[STR:%.*]], i32 0, i32 -1)
> >  ; CHECK-IPRINTF-NEXT:    ret void
> >  ;
> >    %fmt = getelementptr [3 x i8], [3 x i8]* @percent_s, i32 0, i32 0
> >
> >
> > _______________________________________________
> > llvm-commits mailing list
> > llvm-commits at lists.llvm.org
> > https://lists.llvm.org/cgi-bin/mailman/listinfo/llvm-commits