[Mesa-dev] [PATCH] gallivm: Use the LLVM's C disassembly interface.

Roland Scheidegger sroland at vmware.com
Thu May 28 11:26:05 PDT 2015


Looks ok, it's massively simpler and shouldn't break as often.

Reviewed-by: Roland Scheidegger <sroland at vmware.com>

Am 28.05.2015 um 17:57 schrieb Jose Fonseca:
> It doesn't do everything we want.  In particular it doesn't allow to
> detect jumps or return opcodes.  Currently we detect the x86's RET
> opcode.
> 
> Even though it's worse for LLVM 3.3, it's an improvement for LLVM 3.7,
> which was totally busted.
> ---
>  scons/llvm.py                                  |   4 +-
>  src/gallium/auxiliary/gallivm/lp_bld_debug.cpp | 260 ++++---------------------
>  2 files changed, 40 insertions(+), 224 deletions(-)
> 
> diff --git a/scons/llvm.py b/scons/llvm.py
> index 17278df..c59b8cb 100644
> --- a/scons/llvm.py
> +++ b/scons/llvm.py
> @@ -120,6 +120,7 @@ def generate(env):
>              ])
>          elif llvm_version >= distutils.version.LooseVersion('3.5'):
>              env.Prepend(LIBS = [
> +                'LLVMMCDisassembler',
>                  'LLVMBitWriter', 'LLVMMCJIT', 'LLVMRuntimeDyld',
>                  'LLVMX86Disassembler', 'LLVMX86AsmParser', 'LLVMX86CodeGen',
>                  'LLVMSelectionDAG', 'LLVMAsmPrinter', 'LLVMX86Desc',
> @@ -132,6 +133,7 @@ def generate(env):
>              ])
>          else:
>              env.Prepend(LIBS = [
> +                'LLVMMCDisassembler',
>                  'LLVMBitWriter', 'LLVMX86Disassembler', 'LLVMX86AsmParser',
>                  'LLVMX86CodeGen', 'LLVMX86Desc', 'LLVMSelectionDAG',
>                  'LLVMAsmPrinter', 'LLVMMCParser', 'LLVMX86AsmPrinter',
> @@ -189,7 +191,7 @@ def generate(env):
>              if '-fno-rtti' in cxxflags:
>                  env.Append(CXXFLAGS = ['-fno-rtti'])
>  
> -            components = ['engine', 'mcjit', 'bitwriter', 'x86asmprinter']
> +            components = ['engine', 'mcjit', 'bitwriter', 'x86asmprinter', 'mcdisassembler']
>  
>              env.ParseConfig('llvm-config --libs ' + ' '.join(components))
>              env.ParseConfig('llvm-config --ldflags')
> diff --git a/src/gallium/auxiliary/gallivm/lp_bld_debug.cpp b/src/gallium/auxiliary/gallivm/lp_bld_debug.cpp
> index 76c302f..64fb044 100644
> --- a/src/gallium/auxiliary/gallivm/lp_bld_debug.cpp
> +++ b/src/gallium/auxiliary/gallivm/lp_bld_debug.cpp
> @@ -28,40 +28,12 @@
>  #include <stddef.h>
>  
>  #include <llvm-c/Core.h>
> -#include <llvm/Target/TargetMachine.h>
> -#include <llvm/Target/TargetInstrInfo.h>
> +#include <llvm-c/Disassembler.h>
>  #include <llvm/Support/raw_ostream.h>
>  #include <llvm/Support/Format.h>
> -
> -#if HAVE_LLVM >= 0x0306
> -#include <llvm/Target/TargetSubtargetInfo.h>
> -#else
> -#include <llvm/Support/MemoryObject.h>
> -#endif
> -
> -#include <llvm/Support/TargetRegistry.h>
> -#include <llvm/MC/MCSubtargetInfo.h>
> -
>  #include <llvm/Support/Host.h>
> -
>  #include <llvm/IR/Module.h>
>  
> -#include <llvm/MC/MCDisassembler.h>
> -#include <llvm/MC/MCAsmInfo.h>
> -#include <llvm/MC/MCInst.h>
> -#include <llvm/MC/MCInstPrinter.h>
> -#include <llvm/MC/MCRegisterInfo.h>
> -
> -#if HAVE_LLVM >= 0x0305
> -#define OwningPtr std::unique_ptr
> -#else
> -#include <llvm/ADT/OwningPtr.h>
> -#endif
> -
> -#if HAVE_LLVM >= 0x0305
> -#include <llvm/MC/MCContext.h>
> -#endif
> -
>  #include "util/u_math.h"
>  #include "util/u_debug.h"
>  
> @@ -133,7 +105,7 @@ lp_get_module_id(LLVMModuleRef module)
>  extern "C" void
>  lp_debug_dump_value(LLVMValueRef value)
>  {
> -#if (defined(PIPE_OS_WINDOWS) && !defined(PIPE_CC_MSVC)) || defined(PIPE_OS_EMBDDED)
> +#if (defined(PIPE_OS_WINDOWS) && !defined(PIPE_CC_MSVC)) || defined(PIPE_OS_EMBEDDED)
>     raw_debug_ostream os;
>     llvm::unwrap(value)->print(os);
>     os.flush();
> @@ -143,44 +115,16 @@ lp_debug_dump_value(LLVMValueRef value)
>  }
>  
>  
> -#if HAVE_LLVM < 0x0306
> -
> -/*
> - * MemoryObject wrapper around a buffer of memory, to be used by MC
> - * disassembler.
> - */
> -class BufferMemoryObject:
> -   public llvm::MemoryObject
> +static const char *
> +disassemblerSymbolLookupCB(void *DisInfo,
> +                           uint64_t ReferenceValue,
> +                           uint64_t *ReferenceType,
> +                           uint64_t ReferencePC,
> +                           const char **ReferenceName)
>  {
> -private:
> -   const uint8_t *Bytes;
> -   uint64_t Length;
> -public:
> -   BufferMemoryObject(const uint8_t *bytes, uint64_t length) :
> -      Bytes(bytes), Length(length)
> -   {
> -   }
> -
> -   uint64_t getBase() const
> -   {
> -      return 0;
> -   }
> -
> -   uint64_t getExtent() const
> -   {
> -      return Length;
> -   }
> -
> -   int readByte(uint64_t addr, uint8_t *byte) const
> -   {
> -      if (addr > getExtent())
> -         return -1;
> -      *byte = Bytes[addr];
> -      return 0;
> -   }
> -};
> -
> -#endif /* HAVE_LLVM < 0x0306 */
> +   // TODO: Maybe this can be used to guess jumps
> +   return NULL;
> +}
>  
>  
>  /*
> @@ -193,8 +137,6 @@ public:
>  static size_t
>  disassemble(const void* func, llvm::raw_ostream & Out)
>  {
> -   using namespace llvm;
> -
>     const uint8_t *bytes = (const uint8_t *)func;
>  
>     /*
> @@ -202,101 +144,23 @@ disassemble(const void* func, llvm::raw_ostream & Out)
>      */
>     const uint64_t extent = 96 * 1024;
>  
> -   uint64_t max_pc = 0;
> -
>     /*
>      * Initialize all used objects.
>      */
>  
> -   std::string Triple = sys::getDefaultTargetTriple();
> -
> -   std::string Error;
> -   const Target *T = TargetRegistry::lookupTarget(Triple, Error);
> -
> -#if HAVE_LLVM >= 0x0304
> -   OwningPtr<const MCAsmInfo> AsmInfo(T->createMCAsmInfo(*T->createMCRegInfo(Triple), Triple));
> -#else
> -   OwningPtr<const MCAsmInfo> AsmInfo(T->createMCAsmInfo(Triple));
> -#endif
> -
> -   if (!AsmInfo) {
> -      Out << "error: no assembly info for target " << Triple << "\n";
> -      Out.flush();
> -      return 0;
> -   }
> -
> -   unsigned int AsmPrinterVariant = AsmInfo->getAssemblerDialect();
> -
> -   OwningPtr<const MCRegisterInfo> MRI(T->createMCRegInfo(Triple));
> -   if (!MRI) {
> -      Out << "error: no register info for target " << Triple.c_str() << "\n";
> -      Out.flush();
> -      return 0;
> -   }
> -
> -   OwningPtr<const MCInstrInfo> MII(T->createMCInstrInfo());
> -   if (!MII) {
> -      Out << "error: no instruction info for target " << Triple.c_str() << "\n";
> -      Out.flush();
> -      return 0;
> -   }
> +   std::string Triple = llvm::sys::getProcessTriple();
> +   LLVMDisasmContextRef D = LLVMCreateDisasm(Triple.c_str(), NULL, 0, NULL, &disassemblerSymbolLookupCB);
> +   char outline[1024];
>  
> -#if HAVE_LLVM >= 0x0305
> -   OwningPtr<const MCSubtargetInfo> STI(T->createMCSubtargetInfo(Triple, sys::getHostCPUName(), ""));
> -   OwningPtr<MCContext> MCCtx(new MCContext(AsmInfo.get(), MRI.get(), 0));
> -   OwningPtr<const MCDisassembler> DisAsm(T->createMCDisassembler(*STI, *MCCtx));
> -#else
> -   OwningPtr<const MCSubtargetInfo> STI(T->createMCSubtargetInfo(Triple, sys::getHostCPUName(), ""));
> -   OwningPtr<const MCDisassembler> DisAsm(T->createMCDisassembler(*STI));
> -#endif
> -   if (!DisAsm) {
> -      Out << "error: no disassembler for target " << Triple << "\n";
> -      Out.flush();
> +   if (!D) {
> +      Out << "error: couldn't create disassembler for triple " << Triple << "\n";
>        return 0;
>     }
>  
> -
> -#if HAVE_LLVM >= 0x0307
> -   OwningPtr<MCInstPrinter> Printer(
> -         T->createMCInstPrinter(llvm::Triple(Triple), AsmPrinterVariant, *AsmInfo, *MII, *MRI));
> -#else
> -   OwningPtr<MCInstPrinter> Printer(
> -         T->createMCInstPrinter(AsmPrinterVariant, *AsmInfo, *MII, *MRI, *STI));
> -#endif
> -   if (!Printer) {
> -      Out << "error: no instruction printer for target " << Triple.c_str() << "\n";
> -      Out.flush();
> -      return 0;
> -   }
> -
> -   TargetOptions options;
> -#if defined(DEBUG) && HAVE_LLVM < 0x0307
> -   options.JITEmitDebugInfo = true;
> -#endif
> -#if defined(PIPE_ARCH_X86)
> -   options.StackAlignmentOverride = 4;
> -#endif
> -#if defined(DEBUG) || defined(PROFILE)
> -#if HAVE_LLVM < 0x0307
> -   options.NoFramePointerElim = true;
> -#endif
> -#endif
> -   OwningPtr<TargetMachine> TM(T->createTargetMachine(Triple, sys::getHostCPUName(), "", options));
> -
> -   /*
> -    * Wrap the data in a MemoryObject
> -    */
> -#if HAVE_LLVM >= 0x0306
> -   ArrayRef<uint8_t> memoryObject((const uint8_t *)bytes, extent);
> -#else
> -   BufferMemoryObject memoryObject((const uint8_t *)bytes, extent);
> -#endif
> -
>     uint64_t pc;
>     pc = 0;
> -   while (true) {
> -      MCInst Inst;
> -      uint64_t Size;
> +   while (pc < extent) {
> +      size_t Size;
>  
>        /*
>         * Print address.  We use addresses relative to the start of the function,
> @@ -305,11 +169,13 @@ disassemble(const void* func, llvm::raw_ostream & Out)
>  
>        Out << llvm::format("%6lu:\t", (unsigned long)pc);
>  
> -      if (!DisAsm->getInstruction(Inst, Size, memoryObject,
> -                                 pc,
> -				  nulls(), nulls())) {
> -         Out << "invalid";
> +      Size = LLVMDisasmInstruction(D, (uint8_t *)bytes + pc, extent - pc, 0, outline,
> +                                   sizeof outline);
> +
> +      if (!Size) {
> +         Out << "invalid\n";
>           pc += 1;
> +         break;
>        }
>  
>        /*
> @@ -319,7 +185,7 @@ disassemble(const void* func, llvm::raw_ostream & Out)
>        if (0) {
>           unsigned i;
>           for (i = 0; i < Size; ++i) {
> -            Out << llvm::format("%02x ", ((const uint8_t*)bytes)[pc + i]);
> +            Out << llvm::format("%02x ", bytes[pc + i]);
>           }
>           for (; i < 16; ++i) {
>              Out << "   ";
> @@ -329,81 +195,27 @@ disassemble(const void* func, llvm::raw_ostream & Out)
>        /*
>         * Print the instruction.
>         */
> -#if HAVE_LLVM >= 0x0307
> -      Printer->printInst(&Inst, Out, "", *STI);
> -#else
> -      Printer->printInst(&Inst, Out, "");
> -#endif
>  
> -      /*
> -       * Advance.
> -       */
> +      Out << outline;
>  
> -      pc += Size;
> -
> -      const MCInstrDesc &TID = MII->get(Inst.getOpcode());
> +      Out << "\n";
>  
>        /*
> -       * Keep track of forward jumps to a nearby address.
> +       * Stop disassembling on return statements, if there is no record of a
> +       * jump to a successive address.
> +       *
> +       * XXX: This currently assumes x86
>         */
>  
> -      if (TID.isBranch()) {
> -         for (unsigned i = 0; i < Inst.getNumOperands(); ++i) {
> -            const MCOperand &operand = Inst.getOperand(i);
> -            if (operand.isImm()) {
> -               uint64_t jump;
> -
> -               /*
> -                * FIXME: Handle both relative and absolute addresses correctly.
> -                * EDInstInfo actually has this info, but operandTypes and
> -                * operandFlags enums are not exposed in the public interface.
> -                */
> -
> -               if (1) {
> -                  /*
> -                   * PC relative addr.
> -                   */
> -
> -                  jump = pc + operand.getImm();
> -               } else {
> -                  /*
> -                   * Absolute addr.
> -                   */
> -
> -                  jump = (uint64_t)operand.getImm();
> -               }
> -
> -               /*
> -                * Output the address relative to the function start, given
> -                * that MC will print the addresses relative the current pc.
> -                */
> -               Out << "\t\t; " << jump;
> -
> -               /*
> -                * Ignore far jumps given it could be actually a tail return to
> -                * a random address.
> -                */
> -
> -               if (jump > max_pc &&
> -                   jump < extent) {
> -                  max_pc = jump;
> -               }
> -            }
> -         }
> +      if (Size == 1 && bytes[pc] == 0xc3) {
> +         break;
>        }
>  
> -      Out << "\n";
> -
>        /*
> -       * Stop disassembling on return statements, if there is no record of a
> -       * jump to a successive address.
> +       * Advance.
>         */
>  
> -      if (TID.isReturn()) {
> -         if (pc > max_pc) {
> -            break;
> -         }
> -      }
> +      pc += Size;
>  
>        if (pc >= extent) {
>           Out << "disassembly larger than " << extent << "bytes, aborting\n";
> @@ -414,6 +226,8 @@ disassemble(const void* func, llvm::raw_ostream & Out)
>     Out << "\n";
>     Out.flush();
>  
> +   LLVMDisasmDispose(D);
> +
>     /*
>      * Print GDB command, useful to verify output.
>      */
> 



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