From 0d27ca145fff7d71ca2da5d356925a1df6f533ca Mon Sep 17 00:00:00 2001 From: Eric Christopher Date: Thu, 8 Aug 2013 23:45:55 +0000 Subject: [PATCH] Move hash computation code into a separate class and file. No functional change intended. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@188028 91177308-0d34-0410-b5e6-96231b3b80d8 --- lib/CodeGen/AsmPrinter/DIEHash.cpp | 136 ++++++++++++++++++++++++++ lib/CodeGen/AsmPrinter/DIEHash.h | 46 +++++++++ lib/CodeGen/AsmPrinter/DwarfDebug.cpp | 108 ++------------------ 3 files changed, 191 insertions(+), 99 deletions(-) create mode 100644 lib/CodeGen/AsmPrinter/DIEHash.cpp create mode 100644 lib/CodeGen/AsmPrinter/DIEHash.h diff --git a/lib/CodeGen/AsmPrinter/DIEHash.cpp b/lib/CodeGen/AsmPrinter/DIEHash.cpp new file mode 100644 index 00000000000..81ea20a5ffb --- /dev/null +++ b/lib/CodeGen/AsmPrinter/DIEHash.cpp @@ -0,0 +1,136 @@ +//===-- llvm/CodeGen/DIEHash.cpp - Dwarf Hashing Framework ----------------===// +// +// The LLVM Compiler Infrastructure +// +// This file is distributed under the University of Illinois Open Source +// License. See LICENSE.TXT for details. +// +//===----------------------------------------------------------------------===// +// +// This file contains support for DWARF4 hashing of DIEs. +// +//===----------------------------------------------------------------------===// + +#define DEBUG_TYPE "dwarfdebug" + +#include "DIE.h" +#include "DIEHash.h" +#include "DwarfCompileUnit.h" +#include "llvm/ADT/ArrayRef.h" +#include "llvm/ADT/StringRef.h" +#include "llvm/Support/Debug.h" +#include "llvm/Support/Dwarf.h" +#include "llvm/Support/Endian.h" +#include "llvm/Support/MD5.h" +#include "llvm/Support/raw_ostream.h" + +using namespace llvm; + +/// \brief Grabs the string in whichever attribute is passed in and returns +/// a reference to it. +static StringRef getDIEStringAttr(DIE *Die, uint16_t Attr) { + const SmallVectorImpl &Values = Die->getValues(); + const DIEAbbrev &Abbrevs = Die->getAbbrev(); + + // Iterate through all the attributes until we find the one we're + // looking for, if we can't find it return an empty string. + for (size_t i = 0; i < Values.size(); ++i) { + if (Abbrevs.getData()[i].getAttribute() == Attr) { + DIEValue *V = Values[i]; + assert(isa(V) && "String requested. Not a string."); + DIEString *S = cast(V); + return S->getString(); + } + } + return StringRef(""); +} + +/// \brief Adds the string in \p Str to the hash. This also hashes +/// a trailing NULL with the string. +void DIEHash::addString(StringRef Str) { + DEBUG(dbgs() << "Adding string " << Str << " to hash.\n"); + Hash.update(Str); + Hash.update(makeArrayRef((uint8_t)'\0')); +} + +// FIXME: The LEB128 routines are copied and only slightly modified out of +// LEB128.h. + +/// \brief Adds the unsigned in \p Value to the hash encoded as a ULEB128. +void DIEHash::addULEB128(uint64_t Value) { + DEBUG(dbgs() << "Adding ULEB128 " << Value << " to hash.\n"); + do { + uint8_t Byte = Value & 0x7f; + Value >>= 7; + if (Value != 0) + Byte |= 0x80; // Mark this byte to show that more bytes will follow. + Hash.update(Byte); + } while (Value != 0); +} + +/// \brief Including \p Parent adds the context of Parent to the hash.. +void DIEHash::addParentContext(DIE *Parent) { + + DEBUG(dbgs() << "Adding parent context to hash...\n"); + + // [7.27.2] For each surrounding type or namespace beginning with the + // outermost such construct... + SmallVector Parents; + while (Parent->getTag() != dwarf::DW_TAG_compile_unit) { + Parents.push_back(Parent); + Parent = Parent->getParent(); + } + + // Reverse iterate over our list to go from the outermost construct to the + // innermost. + for (SmallVectorImpl::reverse_iterator I = Parents.rbegin(), + E = Parents.rend(); + I != E; ++I) { + DIE *Die = *I; + + // ... Append the letter "C" to the sequence... + addULEB128('C'); + + // ... Followed by the DWARF tag of the construct... + addULEB128(Die->getTag()); + + // ... Then the name, taken from the DW_AT_name attribute. + StringRef Name = getDIEStringAttr(Die, dwarf::DW_AT_name); + DEBUG(dbgs() << "... adding context: " << Name << "\n"); + if (!Name.empty()) + addString(Name); + } +} + +/// This is based on the type signature computation given in section 7.27 of the +/// DWARF4 standard. It is the md5 hash of a flattened description of the DIE +/// with +/// the exception that we are hashing only the context and the name of the type. +uint64_t DIEHash::computeDIEODRSignature(DIE *Die) { + + // Add the contexts to the hash. We won't be computing the ODR hash for + // function local types so it's safe to use the generic context hashing + // algorithm here. + // FIXME: If we figure out how to account for linkage in some way we could + // actually do this with a slight modification to the parent hash algorithm. + DIE *Parent = Die->getParent(); + if (Parent) + addParentContext(Parent); + + // Add the current DIE information. + + // Add the DWARF tag of the DIE. + addULEB128(Die->getTag()); + + // Add the name of the type to the hash. + addString(getDIEStringAttr(Die, dwarf::DW_AT_name)); + + // Now get the result. + MD5::MD5Result Result; + Hash.final(Result); + + // ... take the least significant 8 bytes and return those. Our MD5 + // implementation always returns its results in little endian, swap bytes + // appropriately. + return *reinterpret_cast(Result + 8); +} diff --git a/lib/CodeGen/AsmPrinter/DIEHash.h b/lib/CodeGen/AsmPrinter/DIEHash.h new file mode 100644 index 00000000000..b9f811c91af --- /dev/null +++ b/lib/CodeGen/AsmPrinter/DIEHash.h @@ -0,0 +1,46 @@ +//===-- llvm/CodeGen/DIEHash.h - Dwarf Hashing Framework -------*- C++ -*--===// +// +// The LLVM Compiler Infrastructure +// +// This file is distributed under the University of Illinois Open Source +// License. See LICENSE.TXT for details. +// +//===----------------------------------------------------------------------===// +// +// This file contains support for DWARF4 hashing of DIEs. +// +//===----------------------------------------------------------------------===// + +#include "llvm/Support/MD5.h" + +namespace llvm { + +class CompileUnit; + +/// \brief An object containing the capability of hashing and adding hash +/// attributes onto a DIE. +class DIEHash { +public: + /// \brief Initializes. The hash is default initialized. + DIEHash() {} + + /// \brief Computes the ODR signature + uint64_t computeDIEODRSignature(DIE *Die); + + // Helper routines to process parts of a DIE. + private: + /// \brief Adds the parent context of \param Die to the hash. + void addParentContext(DIE *Die); + + // Routines that add DIEValues to the hash. +private: + /// \brief Encodes and adds \param Value to the hash as a ULEB128. + void addULEB128(uint64_t Value); + + /// \brief Adds \param Str to the hash and includes a NULL byte. + void addString(StringRef Str); + +private: + MD5 Hash; +}; +} diff --git a/lib/CodeGen/AsmPrinter/DwarfDebug.cpp b/lib/CodeGen/AsmPrinter/DwarfDebug.cpp index 7bd2bb2ee50..4a10a0e94cf 100644 --- a/lib/CodeGen/AsmPrinter/DwarfDebug.cpp +++ b/lib/CodeGen/AsmPrinter/DwarfDebug.cpp @@ -14,6 +14,7 @@ #define DEBUG_TYPE "dwarfdebug" #include "DwarfDebug.h" #include "DIE.h" +#include "DIEHash.h" #include "DwarfAccelTable.h" #include "DwarfCompileUnit.h" #include "llvm/ADT/STLExtras.h" @@ -962,8 +963,7 @@ void DwarfDebug::collectDeadVariables() { DeleteContainerSeconds(DeadFnScopeMap); } -// Type Signature [7.27] computation code. -typedef ArrayRef HashValue; +// Type Signature [7.27] and ODR Hash code. /// \brief Grabs the string in whichever attribute is passed in and returns /// a reference to it. Returns "" if the attribute doesn't exist. @@ -976,100 +976,6 @@ static StringRef getDIEStringAttr(DIE *Die, unsigned Attr) { return StringRef(""); } -/// \brief Adds the string in \p Str to the hash in \p Hash. This also hashes -/// a trailing NULL with the string. -static void addStringToHash(MD5 &Hash, StringRef Str) { - DEBUG(dbgs() << "Adding string " << Str << " to hash.\n"); - Hash.update(Str); - Hash.update(makeArrayRef((uint8_t)'\0')); -} - -// FIXME: These are copied and only slightly modified out of LEB128.h. - -/// \brief Adds the unsigned in \p N to the hash in \p Hash. This also encodes -/// the unsigned as a ULEB128. -static void addULEB128ToHash(MD5 &Hash, uint64_t Value) { - DEBUG(dbgs() << "Adding ULEB128 " << Value << " to hash.\n"); - do { - uint8_t Byte = Value & 0x7f; - Value >>= 7; - if (Value != 0) - Byte |= 0x80; // Mark this byte to show that more bytes will follow. - Hash.update(Byte); - } while (Value != 0); -} - -/// \brief Including \p Parent adds the context of Parent to \p Hash. -static void addParentContextToHash(MD5 &Hash, DIE *Parent) { - - DEBUG(dbgs() << "Adding parent context to hash...\n"); - - // [7.27.2] For each surrounding type or namespace beginning with the - // outermost such construct... - SmallVector Parents; - while (Parent->getTag() != dwarf::DW_TAG_compile_unit) { - Parents.push_back(Parent); - Parent = Parent->getParent(); - } - - // Reverse iterate over our list to go from the outermost construct to the - // innermost. - for (SmallVectorImpl::reverse_iterator I = Parents.rbegin(), - E = Parents.rend(); - I != E; ++I) { - DIE *Die = *I; - - // ... Append the letter "C" to the sequence... - addULEB128ToHash(Hash, 'C'); - - // ... Followed by the DWARF tag of the construct... - addULEB128ToHash(Hash, Die->getTag()); - - // ... Then the name, taken from the DW_AT_name attribute. - StringRef Name = getDIEStringAttr(Die, dwarf::DW_AT_name); - DEBUG(dbgs() << "... adding context: " << Name << "\n"); - if (!Name.empty()) - addStringToHash(Hash, Name); - } -} - -/// This is based on the type signature computation given in section 7.27 of the -/// DWARF4 standard. It is the md5 hash of a flattened description of the DIE with -/// the exception that we are hashing only the context and the name of the type. -static void addDIEODRSignature(MD5 &Hash, CompileUnit *CU, DIE *Die) { - - // Add the contexts to the hash. We won't be computing the ODR hash for - // function local types so it's safe to use the generic context hashing - // algorithm here. - // FIXME: If we figure out how to account for linkage in some way we could - // actually do this with a slight modification to the parent hash algorithm. - DIE *Parent = Die->getParent(); - if (Parent) - addParentContextToHash(Hash, Parent); - - // Add the current DIE information. - - // Add the DWARF tag of the DIE. - addULEB128ToHash(Hash, Die->getTag()); - - // Add the name of the type to the hash. - addStringToHash(Hash, getDIEStringAttr(Die, dwarf::DW_AT_name)); - - // Now get the result. - MD5::MD5Result Result; - Hash.final(Result); - - // ... take the least significant 8 bytes and store those as the attribute. - // Our MD5 implementation always returns its results in little endian, swap - // bytes appropriately. - uint64_t Signature = *reinterpret_cast(Result + 8); - - // FIXME: This should be added onto the type unit, not the type, but this - // works as an intermediate stage. - CU->addUInt(Die, dwarf::DW_AT_GNU_odr_signature, dwarf::DW_FORM_data8, - Signature); -} - /// Return true if the current DIE is contained within an anonymous namespace. static bool isContainedInAnonNamespace(DIE *Die) { DIE *Parent = Die->getParent(); @@ -1090,7 +996,7 @@ static bool shouldAddODRHash(CompileUnit *CU, DIE *Die) { return CU->getLanguage() == dwarf::DW_LANG_C_plus_plus && getDIEStringAttr(Die, dwarf::DW_AT_name) != "" && !isContainedInAnonNamespace(Die); - } +} void DwarfDebug::finalizeModuleInfo() { // Collect info for variables that were optimized out. @@ -1111,12 +1017,16 @@ void DwarfDebug::finalizeModuleInfo() { // out type. // FIXME: Do type splitting. for (unsigned i = 0, e = TypeUnits.size(); i != e; ++i) { - MD5 Hash; DIE *Die = TypeUnits[i]; + DIEHash Hash; // If we've requested ODR hashes and it's applicable for an ODR hash then // add the ODR signature now. + // FIXME: This should be added onto the type unit, not the type, but this + // works as an intermediate stage. if (GenerateODRHash && shouldAddODRHash(CUMap.begin()->second, Die)) - addDIEODRSignature(Hash, CUMap.begin()->second, Die); + CUMap.begin()->second->addUInt(Die, dwarf::DW_AT_GNU_odr_signature, + dwarf::DW_FORM_data8, + Hash.computeDIEODRSignature(Die)); } // Compute DIE offsets and sizes. -- 2.34.1