[cfe-commits] r165143 - /cfe/trunk/lib/CodeGen/TargetInfo.cpp

Hal Finkel hfinkel at anl.gov
Wed Oct 3 14:21:16 PDT 2012


On Wed, 03 Oct 2012 15:53:20 -0500
"William J. Schmidt" <wschmidt at linux.vnet.ibm.com> wrote:

> On Wed, 2012-10-03 at 14:28 -0500, Hal Finkel wrote:
> > On Wed, 03 Oct 2012 19:18:57 -0000
> > Bill Schmidt <wschmidt at linux.vnet.ibm.com> wrote:
> > 
> > > Author: wschmidt
> > > Date: Wed Oct  3 14:18:57 2012
> > > New Revision: 165143
> > > 
> > > URL: http://llvm.org/viewvc/llvm-project?rev=165143&view=rev
> > > Log:
> > > This patch enables general varargs support for the 64-bit PPC SVR4
> > > ABI.
> > > 
> > > Most of the pieces for this were already in place, but a proper
> > > EmitVAArg is needed for aggregates and complex numbers to be
> > > handled.  Although the va_list for 64-bit PowerPC SVR4 consists of
> > > GPRs 3 through 10 together with the overflow portion of the
> > > parameter save area, we can treat va_list as pointing to
> > > contiguous memory for all parameters, since the back end forces
> > > the parameter GPRs to memory for varargs functions.
> > > 
> > > There is no need at this time to model parameters and return
> > > values beyond what the DefaultABIInfo provides.
> > 
> > I realize that this fixes some test-suite unit tests, but we should
> > probably have a clang codegen regression test as well.
> > 
> >  -Hal
> > 
> 
> OK.  How does the following look?
> 
> // REQUIRES: ppc64-registered-target
> // RUN: %clang_cc1 -triple powerpc64-unknown-linux-gnu -emit-llvm -o
> - %s | FileCheck %s
> 
> #include <stdarg.h>
> 
> struct x {
>   long a;
>   double b;
> };
> 
> double testva (int n, ...)
> {
>   int i;
>   double result = 1.0;
>   va_list ap;
>   va_start(ap, n);
> 
>   for (i = 0; i < n; i++)
>     {
>       struct x t = va_arg (ap, struct x);
> // CHECK: bitcast i8* %ap.cur to %struct.x*
> // CHECK: bitcast %struct.x* %t to i8*
> // CHECK: bitcast %struct.x* %{{[0-9]+}} to i8*
> // CHECK: call void @llvm.memcpy
>       result *= t.b;

I think that this is certainly the right general idea. Does this cover
the various other cases that call CreateIntToPtr? Otherwise, LGTM.

 -Hal

>     }
> 
>   return result;
> }
> 
> 
> Seems to work.  If this is OK, I'll commit it shortly.
> 
> Thanks,
> Bill
> 
> > > 
> > > Modified:
> > >     cfe/trunk/lib/CodeGen/TargetInfo.cpp
> > > 
> > > Modified: cfe/trunk/lib/CodeGen/TargetInfo.cpp
> > > URL:
> > > http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/CodeGen/TargetInfo.cpp?rev=165143&r1=165142&r2=165143&view=diff
> > > ==============================================================================
> > > --- cfe/trunk/lib/CodeGen/TargetInfo.cpp (original) +++
> > > cfe/trunk/lib/CodeGen/TargetInfo.cpp Wed Oct  3 14:18:57 2012 @@
> > > -2581,6 +2581,39 @@ // PowerPC-64
> > >  
> > >  namespace {
> > > +/// PPC64_SVR4_ABIInfo - The 64-bit PowerPC ELF (SVR4) ABI
> > > information. +class PPC64_SVR4_ABIInfo : public DefaultABIInfo {
> > > +
> > > +public:
> > > +  PPC64_SVR4_ABIInfo(CodeGen::CodeGenTypes &CGT) :
> > > DefaultABIInfo(CGT) {} +
> > > +  // TODO: Could override computeInfo to model the ABI more
> > > completely if
> > > +  // it would be helpful.  Example: We might remove the byVal
> > > flag from
> > > +  // aggregate arguments that fit in a register to avoid pushing
> > > them to
> > > +  // memory on function entry.  Note that this is a performance
> > > optimization,
> > > +  // not a compliance issue.  In general we prefer to keep ABI
> > > details in
> > > +  // the back end where possible, but modifying an argument flag
> > > seems like
> > > +  // a good thing to do before invoking the back end.
> > > +
> > > +  virtual llvm::Value *EmitVAArg(llvm::Value *VAListAddr, 
> > > +                                 QualType Ty,
> > > +                                 CodeGenFunction &CGF) const;
> > > +};
> > > +
> > > +class PPC64_SVR4_TargetCodeGenInfo : public TargetCodeGenInfo {
> > > +public:
> > > +  PPC64_SVR4_TargetCodeGenInfo(CodeGenTypes &CGT)
> > > +    : TargetCodeGenInfo(new PPC64_SVR4_ABIInfo(CGT)) {}
> > > +
> > > +  int getDwarfEHStackPointer(CodeGen::CodeGenModule &M) const {
> > > +    // This is recovered from gcc output.
> > > +    return 1; // r1 is the dedicated stack pointer
> > > +  }
> > > +
> > > +  bool initDwarfEHRegSizeTable(CodeGen::CodeGenFunction &CGF,
> > > +                               llvm::Value *Address) const;
> > > +};
> > > +
> > >  class PPC64TargetCodeGenInfo : public DefaultTargetCodeGenInfo {
> > >  public:
> > >    PPC64TargetCodeGenInfo(CodeGenTypes &CGT) :
> > > DefaultTargetCodeGenInfo(CGT) {} @@ -2596,9 +2629,56 @@
> > >  
> > >  }
> > >  
> > > -bool
> > > -PPC64TargetCodeGenInfo::initDwarfEHRegSizeTable(CodeGen::CodeGenFunction
> > > &CGF,
> > > -                                                llvm::Value
> > > *Address) const { +// Based on ARMABIInfo::EmitVAArg, adjusted for
> > > 64-bit machine. +llvm::Value
> > > *PPC64_SVR4_ABIInfo::EmitVAArg(llvm::Value *VAListAddr,
> > > +                                           QualType Ty,
> > > +                                           CodeGenFunction &CGF)
> > > const {
> > > +  llvm::Type *BP = CGF.Int8PtrTy;
> > > +  llvm::Type *BPP = CGF.Int8PtrPtrTy;
> > > +
> > > +  CGBuilderTy &Builder = CGF.Builder;
> > > +  llvm::Value *VAListAddrAsBPP =
> > > Builder.CreateBitCast(VAListAddr, BPP, "ap");
> > > +  llvm::Value *Addr = Builder.CreateLoad(VAListAddrAsBPP,
> > > "ap.cur"); +
> > > +  // Handle address alignment for type alignment > 64 bits.
> > > Although
> > > +  // long double normally requires 16-byte alignment, this is
> > > not the
> > > +  // case when it is passed as an argument; so handle that
> > > special case.
> > > +  const BuiltinType *BT = Ty->getAs<BuiltinType>();
> > > +  unsigned TyAlign = CGF.getContext().getTypeAlign(Ty) / 8;
> > > +
> > > +  if (TyAlign > 8 && (!BT || !BT->isFloatingPoint())) {
> > > +    assert((TyAlign & (TyAlign - 1)) == 0 &&
> > > +           "Alignment is not power of 2!");
> > > +    llvm::Value *AddrAsInt = Builder.CreatePtrToInt(Addr,
> > > CGF.Int64Ty);
> > > +    AddrAsInt = Builder.CreateAdd(AddrAsInt,
> > > Builder.getInt64(TyAlign - 1));
> > > +    AddrAsInt = Builder.CreateAnd(AddrAsInt,
> > > Builder.getInt64(~(TyAlign - 1)));
> > > +    Addr = Builder.CreateIntToPtr(AddrAsInt, BP);
> > > +  }
> > > +
> > > +  // Update the va_list pointer.
> > > +  unsigned SizeInBytes = CGF.getContext().getTypeSize(Ty) / 8;
> > > +  unsigned Offset = llvm::RoundUpToAlignment(SizeInBytes, 8);
> > > +  llvm::Value *NextAddr =
> > > +    Builder.CreateGEP(Addr, llvm::ConstantInt::get(CGF.Int64Ty,
> > > Offset),
> > > +                      "ap.next");
> > > +  Builder.CreateStore(NextAddr, VAListAddrAsBPP);
> > > +
> > > +  // If the argument is smaller than 8 bytes, it is
> > > right-adjusted in
> > > +  // its doubleword slot.  Adjust the pointer to pick it up from
> > > the
> > > +  // correct offset.
> > > +  if (SizeInBytes < 8) {
> > > +    llvm::Value *AddrAsInt = Builder.CreatePtrToInt(Addr,
> > > CGF.Int64Ty);
> > > +    AddrAsInt = Builder.CreateAdd(AddrAsInt, Builder.getInt64(8 -
> > > SizeInBytes));
> > > +    Addr = Builder.CreateIntToPtr(AddrAsInt, BP);
> > > +  }
> > > +
> > > +  llvm::Type *PTy =
> > > llvm::PointerType::getUnqual(CGF.ConvertType(Ty));
> > > +  return Builder.CreateBitCast(Addr, PTy);
> > > +}
> > > +
> > > +static bool
> > > +PPC64_initDwarfEHRegSizeTable(CodeGen::CodeGenFunction &CGF,
> > > +                              llvm::Value *Address) {
> > >    // This is calculated from the LLVM and GCC tables and verified
> > >    // against gcc output.  AFAIK all ABIs use the same encoding.
> > >  
> > > @@ -2637,6 +2717,21 @@
> > >    return false;
> > >  }
> > >  
> > > +bool
> > > +PPC64_SVR4_TargetCodeGenInfo::initDwarfEHRegSizeTable(
> > > +  CodeGen::CodeGenFunction &CGF,
> > > +  llvm::Value *Address) const {
> > > +
> > > +  return PPC64_initDwarfEHRegSizeTable(CGF, Address);
> > > +}
> > > +
> > > +bool
> > > +PPC64TargetCodeGenInfo::initDwarfEHRegSizeTable(CodeGen::CodeGenFunction
> > > &CGF,
> > > +                                                llvm::Value
> > > *Address) const { +
> > > +  return PPC64_initDwarfEHRegSizeTable(CGF, Address);
> > > +}
> > > +
> > >  //===----------------------------------------------------------------------===//
> > >  // ARM ABI Implementation
> > >  //===----------------------------------------------------------------------===//
> > > @@ -3878,7 +3973,10 @@
> > >    case llvm::Triple::ppc:
> > >      return *(TheTargetCodeGenInfo = new
> > > PPC32TargetCodeGenInfo(Types)); case llvm::Triple::ppc64:
> > > -    return *(TheTargetCodeGenInfo = new
> > > PPC64TargetCodeGenInfo(Types));
> > > +    if (Triple.isOSBinFormatELF())
> > > +      return *(TheTargetCodeGenInfo = new
> > > PPC64_SVR4_TargetCodeGenInfo(Types));
> > > +    else
> > > +      return *(TheTargetCodeGenInfo = new
> > > PPC64TargetCodeGenInfo(Types)); 
> > >    case llvm::Triple::nvptx:
> > >    case llvm::Triple::nvptx64:
> > > 
> > > 
> > > _______________________________________________
> > > cfe-commits mailing list
> > > cfe-commits at cs.uiuc.edu
> > > http://lists.cs.uiuc.edu/mailman/listinfo/cfe-commits
> > 
> > 
> > 
> 



-- 
Hal Finkel
Postdoctoral Appointee
Leadership Computing Facility
Argonne National Laboratory



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