src/llvm-project/clang/lib/Frontend/LayoutOverrideSource.cpp - toolchain/rustc - Git at Google

 //===--- LayoutOverrideSource.cpp --Override Record Layouts ---------------===//
 //
 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
 // See https://llvm.org/LICENSE.txt for license information.
 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
 //
 //===----------------------------------------------------------------------===//
 #include "clang/Frontend/LayoutOverrideSource.h"
 #include "clang/AST/Decl.h"
 #include "clang/AST/DeclCXX.h"
 #include "clang/Basic/CharInfo.h"
 #include "llvm/Support/raw_ostream.h"
 #include <fstream>
 #include <string>

 using namespace clang;

 /// Parse a simple identifier.
 static std::string parseName(StringRef S) {
   if (S.empty() || !isAsciiIdentifierStart(S[0]))
     return "";

   unsigned Offset = 1;
   while (Offset < S.size() && isAsciiIdentifierContinue(S[Offset]))
     ++Offset;

   return S.substr(0, Offset).str();
 }

 /// Parse an unsigned integer and move S to the next non-digit character.
 static bool parseUnsigned(StringRef &S, unsigned long long &ULL) {
   if (S.empty() || !isDigit(S[0]))
     return false;
   unsigned Idx = 1;
   while (Idx < S.size() && isDigit(S[Idx]))
     ++Idx;
   (void)S.substr(0, Idx).getAsInteger(10, ULL);
   S = S.substr(Idx);
   return true;
 }

 LayoutOverrideSource::LayoutOverrideSource(StringRef Filename) {
   std::ifstream Input(Filename.str().c_str());
   if (!Input.is_open())
     return;

   // Parse the output of -fdump-record-layouts.
   std::string CurrentType;
   Layout CurrentLayout;
   bool ExpectingType = false;

   while (Input.good()) {
     std::string Line;
     getline(Input, Line);

     StringRef LineStr(Line);

     // Determine whether the following line will start a
     if (LineStr.contains("*** Dumping AST Record Layout")) {
       // Flush the last type/layout, if there is one.
       if (!CurrentType.empty())
         Layouts[CurrentType] = CurrentLayout;
       CurrentLayout = Layout();

       ExpectingType = true;
       continue;
     }

     // If we're expecting a type, grab it.
     if (ExpectingType) {
       ExpectingType = false;

       StringRef::size_type Pos;
       if ((Pos = LineStr.find("struct ")) != StringRef::npos)
         LineStr = LineStr.substr(Pos + strlen("struct "));
       else if ((Pos = LineStr.find("class ")) != StringRef::npos)
         LineStr = LineStr.substr(Pos + strlen("class "));
       else if ((Pos = LineStr.find("union ")) != StringRef::npos)
         LineStr = LineStr.substr(Pos + strlen("union "));
       else
         continue;

       // Find the name of the type.
       CurrentType = parseName(LineStr);
       CurrentLayout = Layout();
       continue;
     }

     // Check for the size of the type.
     StringRef::size_type Pos = LineStr.find(" Size:");
     if (Pos != StringRef::npos) {
       // Skip past the " Size:" prefix.
       LineStr = LineStr.substr(Pos + strlen(" Size:"));

       unsigned long long Size = 0;
       if (parseUnsigned(LineStr, Size))
         CurrentLayout.Size = Size;
       continue;
     }

     // Check for the alignment of the type.
     Pos = LineStr.find("Alignment:");
     if (Pos != StringRef::npos) {
       // Skip past the "Alignment:" prefix.
       LineStr = LineStr.substr(Pos + strlen("Alignment:"));

       unsigned long long Alignment = 0;
       if (parseUnsigned(LineStr, Alignment))
         CurrentLayout.Align = Alignment;
       continue;
     }

     // Check for the size/alignment of the type. The number follows "size=" or
     // "align=" indicates number of bytes.
     Pos = LineStr.find("sizeof=");
     if (Pos != StringRef::npos) {
       /* Skip past the sizeof= prefix. */
       LineStr = LineStr.substr(Pos + strlen("sizeof="));

       // Parse size.
       unsigned long long Size = 0;
       if (parseUnsigned(LineStr, Size))
         CurrentLayout.Size = Size * 8;

       Pos = LineStr.find("align=");
       if (Pos != StringRef::npos) {
         /* Skip past the align= prefix. */
         LineStr = LineStr.substr(Pos + strlen("align="));

         // Parse alignment.
         unsigned long long Alignment = 0;
         if (parseUnsigned(LineStr, Alignment))
           CurrentLayout.Align = Alignment * 8;
       }

       continue;
     }

     // Check for the field offsets of the type.
     Pos = LineStr.find("FieldOffsets: [");
     if (Pos != StringRef::npos) {
       LineStr = LineStr.substr(Pos + strlen("FieldOffsets: ["));
       while (!LineStr.empty() && isDigit(LineStr[0])) {
         unsigned long long Offset = 0;
         if (parseUnsigned(LineStr, Offset))
           CurrentLayout.FieldOffsets.push_back(Offset);

         // Skip over this offset, the following comma, and any spaces.
         LineStr = LineStr.substr(1);
         while (!LineStr.empty() && isWhitespace(LineStr[0]))
           LineStr = LineStr.substr(1);
       }
     }

     // Check for the virtual base offsets.
     Pos = LineStr.find("VBaseOffsets: [");
     if (Pos != StringRef::npos) {
       LineStr = LineStr.substr(Pos + strlen("VBaseOffsets: ["));
       while (!LineStr.empty() && isDigit(LineStr[0])) {
         unsigned long long Offset = 0;
         if (parseUnsigned(LineStr, Offset))
           CurrentLayout.VBaseOffsets.push_back(CharUnits::fromQuantity(Offset));

         // Skip over this offset, the following comma, and any spaces.
         LineStr = LineStr.substr(1);
         while (!LineStr.empty() && isWhitespace(LineStr[0]))
           LineStr = LineStr.substr(1);
       }
       continue;
     }

     // Check for the base offsets.
     Pos = LineStr.find("BaseOffsets: [");
     if (Pos != StringRef::npos) {
       LineStr = LineStr.substr(Pos + strlen("BaseOffsets: ["));
       while (!LineStr.empty() && isDigit(LineStr[0])) {
         unsigned long long Offset = 0;
         if (parseUnsigned(LineStr, Offset))
           CurrentLayout.BaseOffsets.push_back(CharUnits::fromQuantity(Offset));

         // Skip over this offset, the following comma, and any spaces.
         LineStr = LineStr.substr(1);
         while (!LineStr.empty() && isWhitespace(LineStr[0]))
           LineStr = LineStr.substr(1);
       }
     }
   }

   // Flush the last type/layout, if there is one.
   if (!CurrentType.empty())
     Layouts[CurrentType] = CurrentLayout;
 }

 bool
 LayoutOverrideSource::layoutRecordType(const RecordDecl *Record,
   uint64_t &Size, uint64_t &Alignment,
   llvm::DenseMap<const FieldDecl *, uint64_t> &FieldOffsets,
   llvm::DenseMap<const CXXRecordDecl *, CharUnits> &BaseOffsets,
   llvm::DenseMap<const CXXRecordDecl *, CharUnits> &VirtualBaseOffsets)
 {
   // We can't override unnamed declarations.
   if (!Record->getIdentifier())
     return false;

   // Check whether we have a layout for this record.
   llvm::StringMap<Layout>::iterator Known = Layouts.find(Record->getName());
   if (Known == Layouts.end())
     return false;

   // Provide field layouts.
   unsigned NumFields = 0;
   for (RecordDecl::field_iterator F = Record->field_begin(),
                                FEnd = Record->field_end();
        F != FEnd; ++F, ++NumFields) {
     if (NumFields >= Known->second.FieldOffsets.size())
       continue;

     FieldOffsets[*F] = Known->second.FieldOffsets[NumFields];
   }

   // Wrong number of fields.
   if (NumFields != Known->second.FieldOffsets.size())
     return false;

   // Provide base offsets.
   if (const auto *RD = dyn_cast<CXXRecordDecl>(Record)) {
     unsigned NumNB = 0;
     unsigned NumVB = 0;
     for (const auto &I : RD->vbases()) {
       if (NumVB >= Known->second.VBaseOffsets.size())
         continue;
       const CXXRecordDecl *VBase = I.getType()->getAsCXXRecordDecl();
       VirtualBaseOffsets[VBase] = Known->second.VBaseOffsets[NumVB++];
     }
     for (const auto &I : RD->bases()) {
       if (I.isVirtual() || NumNB >= Known->second.BaseOffsets.size())
         continue;
       const CXXRecordDecl *Base = I.getType()->getAsCXXRecordDecl();
       BaseOffsets[Base] = Known->second.BaseOffsets[NumNB++];
     }
   }

   Size = Known->second.Size;
   Alignment = Known->second.Align;
   return true;
 }

 LLVM_DUMP_METHOD void LayoutOverrideSource::dump() {
   raw_ostream &OS = llvm::errs();
   for (llvm::StringMap<Layout>::iterator L = Layouts.begin(),
                                       LEnd = Layouts.end();
        L != LEnd; ++L) {
     OS << "Type: blah " << L->first() << '\n';
     OS << "  Size:" << L->second.Size << '\n';
     OS << "  Alignment:" << L->second.Align << '\n';
     OS << "  FieldOffsets: [";
     for (unsigned I = 0, N = L->second.FieldOffsets.size(); I != N; ++I) {
       if (I)
         OS << ", ";
       OS << L->second.FieldOffsets[I];
     }
     OS << "]\n";
   }
 }
	//===--- LayoutOverrideSource.cpp --Override Record Layouts ---------------===//
	//
	// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
	// See https://llvm.org/LICENSE.txt for license information.
	// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
	//
	//===----------------------------------------------------------------------===//
	#include "clang/Frontend/LayoutOverrideSource.h"
	#include "clang/AST/Decl.h"
	#include "clang/AST/DeclCXX.h"
	#include "clang/Basic/CharInfo.h"
	#include "llvm/Support/raw_ostream.h"
	#include <fstream>
	#include <string>

	using namespace clang;

	/// Parse a simple identifier.
	static std::string parseName(StringRef S) {
	if (S.empty() \|\| !isAsciiIdentifierStart(S[0]))
	return "";

	unsigned Offset = 1;
	while (Offset < S.size() && isAsciiIdentifierContinue(S[Offset]))
	++Offset;

	return S.substr(0, Offset).str();
	}

	/// Parse an unsigned integer and move S to the next non-digit character.
	static bool parseUnsigned(StringRef &S, unsigned long long &ULL) {
	if (S.empty() \|\| !isDigit(S[0]))
	return false;
	unsigned Idx = 1;
	while (Idx < S.size() && isDigit(S[Idx]))
	++Idx;
	(void)S.substr(0, Idx).getAsInteger(10, ULL);
	S = S.substr(Idx);
	return true;
	}

	LayoutOverrideSource::LayoutOverrideSource(StringRef Filename) {
	std::ifstream Input(Filename.str().c_str());
	if (!Input.is_open())
	return;

	// Parse the output of -fdump-record-layouts.
	std::string CurrentType;
	Layout CurrentLayout;
	bool ExpectingType = false;

	while (Input.good()) {
	std::string Line;
	getline(Input, Line);

	StringRef LineStr(Line);

	// Determine whether the following line will start a
	if (LineStr.contains("*** Dumping AST Record Layout")) {
	// Flush the last type/layout, if there is one.
	if (!CurrentType.empty())
	Layouts[CurrentType] = CurrentLayout;
	CurrentLayout = Layout();

	ExpectingType = true;
	continue;
	}

	// If we're expecting a type, grab it.
	if (ExpectingType) {
	ExpectingType = false;

	StringRef::size_type Pos;
	if ((Pos = LineStr.find("struct ")) != StringRef::npos)
	LineStr = LineStr.substr(Pos + strlen("struct "));
	else if ((Pos = LineStr.find("class ")) != StringRef::npos)
	LineStr = LineStr.substr(Pos + strlen("class "));
	else if ((Pos = LineStr.find("union ")) != StringRef::npos)
	LineStr = LineStr.substr(Pos + strlen("union "));
	else
	continue;

	// Find the name of the type.
	CurrentType = parseName(LineStr);
	CurrentLayout = Layout();
	continue;
	}

	// Check for the size of the type.
	StringRef::size_type Pos = LineStr.find(" Size:");
	if (Pos != StringRef::npos) {
	// Skip past the " Size:" prefix.
	LineStr = LineStr.substr(Pos + strlen(" Size:"));

	unsigned long long Size = 0;
	if (parseUnsigned(LineStr, Size))
	CurrentLayout.Size = Size;
	continue;
	}

	// Check for the alignment of the type.
	Pos = LineStr.find("Alignment:");
	if (Pos != StringRef::npos) {
	// Skip past the "Alignment:" prefix.
	LineStr = LineStr.substr(Pos + strlen("Alignment:"));

	unsigned long long Alignment = 0;
	if (parseUnsigned(LineStr, Alignment))
	CurrentLayout.Align = Alignment;
	continue;
	}

	// Check for the size/alignment of the type. The number follows "size=" or
	// "align=" indicates number of bytes.
	Pos = LineStr.find("sizeof=");
	if (Pos != StringRef::npos) {
	/* Skip past the sizeof= prefix. */
	LineStr = LineStr.substr(Pos + strlen("sizeof="));

	// Parse size.
	unsigned long long Size = 0;
	if (parseUnsigned(LineStr, Size))
	CurrentLayout.Size = Size * 8;

	Pos = LineStr.find("align=");
	if (Pos != StringRef::npos) {
	/* Skip past the align= prefix. */
	LineStr = LineStr.substr(Pos + strlen("align="));

	// Parse alignment.
	unsigned long long Alignment = 0;
	if (parseUnsigned(LineStr, Alignment))
	CurrentLayout.Align = Alignment * 8;
	}

	continue;
	}

	// Check for the field offsets of the type.
	Pos = LineStr.find("FieldOffsets: [");
	if (Pos != StringRef::npos) {
	LineStr = LineStr.substr(Pos + strlen("FieldOffsets: ["));
	while (!LineStr.empty() && isDigit(LineStr[0])) {
	unsigned long long Offset = 0;
	if (parseUnsigned(LineStr, Offset))
	CurrentLayout.FieldOffsets.push_back(Offset);

	// Skip over this offset, the following comma, and any spaces.
	LineStr = LineStr.substr(1);
	while (!LineStr.empty() && isWhitespace(LineStr[0]))
	LineStr = LineStr.substr(1);
	}
	}

	// Check for the virtual base offsets.
	Pos = LineStr.find("VBaseOffsets: [");
	if (Pos != StringRef::npos) {
	LineStr = LineStr.substr(Pos + strlen("VBaseOffsets: ["));
	while (!LineStr.empty() && isDigit(LineStr[0])) {
	unsigned long long Offset = 0;
	if (parseUnsigned(LineStr, Offset))
	CurrentLayout.VBaseOffsets.push_back(CharUnits::fromQuantity(Offset));

	// Skip over this offset, the following comma, and any spaces.
	LineStr = LineStr.substr(1);
	while (!LineStr.empty() && isWhitespace(LineStr[0]))
	LineStr = LineStr.substr(1);
	}
	continue;
	}

	// Check for the base offsets.
	Pos = LineStr.find("BaseOffsets: [");
	if (Pos != StringRef::npos) {
	LineStr = LineStr.substr(Pos + strlen("BaseOffsets: ["));
	while (!LineStr.empty() && isDigit(LineStr[0])) {
	unsigned long long Offset = 0;
	if (parseUnsigned(LineStr, Offset))
	CurrentLayout.BaseOffsets.push_back(CharUnits::fromQuantity(Offset));

	// Skip over this offset, the following comma, and any spaces.
	LineStr = LineStr.substr(1);
	while (!LineStr.empty() && isWhitespace(LineStr[0]))
	LineStr = LineStr.substr(1);
	}
	}
	}

	// Flush the last type/layout, if there is one.
	if (!CurrentType.empty())
	Layouts[CurrentType] = CurrentLayout;
	}

	bool
	LayoutOverrideSource::layoutRecordType(const RecordDecl *Record,
	uint64_t &Size, uint64_t &Alignment,
	llvm::DenseMap<const FieldDecl *, uint64_t> &FieldOffsets,
	llvm::DenseMap<const CXXRecordDecl *, CharUnits> &BaseOffsets,
	llvm::DenseMap<const CXXRecordDecl *, CharUnits> &VirtualBaseOffsets)
	{
	// We can't override unnamed declarations.
	if (!Record->getIdentifier())
	return false;

	// Check whether we have a layout for this record.
	llvm::StringMap<Layout>::iterator Known = Layouts.find(Record->getName());
	if (Known == Layouts.end())
	return false;

	// Provide field layouts.
	unsigned NumFields = 0;
	for (RecordDecl::field_iterator F = Record->field_begin(),
	FEnd = Record->field_end();
	F != FEnd; ++F, ++NumFields) {
	if (NumFields >= Known->second.FieldOffsets.size())
	continue;

	FieldOffsets[*F] = Known->second.FieldOffsets[NumFields];
	}

	// Wrong number of fields.
	if (NumFields != Known->second.FieldOffsets.size())
	return false;

	// Provide base offsets.
	if (const auto *RD = dyn_cast<CXXRecordDecl>(Record)) {
	unsigned NumNB = 0;
	unsigned NumVB = 0;
	for (const auto &I : RD->vbases()) {
	if (NumVB >= Known->second.VBaseOffsets.size())
	continue;
	const CXXRecordDecl *VBase = I.getType()->getAsCXXRecordDecl();
	VirtualBaseOffsets[VBase] = Known->second.VBaseOffsets[NumVB++];
	}
	for (const auto &I : RD->bases()) {
	if (I.isVirtual() \|\| NumNB >= Known->second.BaseOffsets.size())
	continue;
	const CXXRecordDecl *Base = I.getType()->getAsCXXRecordDecl();
	BaseOffsets[Base] = Known->second.BaseOffsets[NumNB++];
	}
	}

	Size = Known->second.Size;
	Alignment = Known->second.Align;
	return true;
	}

	LLVM_DUMP_METHOD void LayoutOverrideSource::dump() {
	raw_ostream &OS = llvm::errs();
	for (llvm::StringMap<Layout>::iterator L = Layouts.begin(),
	LEnd = Layouts.end();
	L != LEnd; ++L) {
	OS << "Type: blah " << L->first() << '\n';
	OS << " Size:" << L->second.Size << '\n';
	OS << " Alignment:" << L->second.Align << '\n';
	OS << " FieldOffsets: [";
	for (unsigned I = 0, N = L->second.FieldOffsets.size(); I != N; ++I) {
	if (I)
	OS << ", ";
	OS << L->second.FieldOffsets[I];
	}
	OS << "]\n";
	}
	}