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263 lines
8.2 KiB
C++
263 lines
8.2 KiB
C++
//===--- LayoutOverrideSource.cpp --Override Record Layouts ---------------===//
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//
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// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
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// See https://llvm.org/LICENSE.txt for license information.
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// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
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//
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//===----------------------------------------------------------------------===//
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#include "clang/Frontend/LayoutOverrideSource.h"
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#include "clang/AST/Decl.h"
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#include "clang/AST/DeclCXX.h"
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#include "clang/Basic/CharInfo.h"
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#include "llvm/Support/raw_ostream.h"
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#include <fstream>
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#include <string>
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using namespace clang;
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/// Parse a simple identifier.
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static std::string parseName(StringRef S) {
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if (S.empty() || !isAsciiIdentifierStart(S[0]))
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return "";
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unsigned Offset = 1;
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while (Offset < S.size() && isAsciiIdentifierContinue(S[Offset]))
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++Offset;
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return S.substr(0, Offset).str();
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}
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/// Parse an unsigned integer and move S to the next non-digit character.
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static bool parseUnsigned(StringRef &S, unsigned long long &ULL) {
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if (S.empty() || !isDigit(S[0]))
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return false;
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unsigned Idx = 1;
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while (Idx < S.size() && isDigit(S[Idx]))
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++Idx;
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(void)S.substr(0, Idx).getAsInteger(10, ULL);
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S = S.substr(Idx);
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return true;
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}
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LayoutOverrideSource::LayoutOverrideSource(StringRef Filename) {
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std::ifstream Input(Filename.str().c_str());
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if (!Input.is_open())
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return;
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// Parse the output of -fdump-record-layouts.
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std::string CurrentType;
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Layout CurrentLayout;
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bool ExpectingType = false;
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while (Input.good()) {
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std::string Line;
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getline(Input, Line);
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StringRef LineStr(Line);
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// Determine whether the following line will start a
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if (LineStr.contains("*** Dumping AST Record Layout")) {
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// Flush the last type/layout, if there is one.
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if (!CurrentType.empty())
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Layouts[CurrentType] = CurrentLayout;
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CurrentLayout = Layout();
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ExpectingType = true;
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continue;
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}
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// If we're expecting a type, grab it.
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if (ExpectingType) {
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ExpectingType = false;
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StringRef::size_type Pos;
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if ((Pos = LineStr.find("struct ")) != StringRef::npos)
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LineStr = LineStr.substr(Pos + strlen("struct "));
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else if ((Pos = LineStr.find("class ")) != StringRef::npos)
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LineStr = LineStr.substr(Pos + strlen("class "));
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else if ((Pos = LineStr.find("union ")) != StringRef::npos)
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LineStr = LineStr.substr(Pos + strlen("union "));
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else
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continue;
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// Find the name of the type.
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CurrentType = parseName(LineStr);
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CurrentLayout = Layout();
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continue;
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}
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// Check for the size of the type.
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StringRef::size_type Pos = LineStr.find(" Size:");
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if (Pos != StringRef::npos) {
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// Skip past the " Size:" prefix.
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LineStr = LineStr.substr(Pos + strlen(" Size:"));
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unsigned long long Size = 0;
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if (parseUnsigned(LineStr, Size))
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CurrentLayout.Size = Size;
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continue;
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}
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// Check for the alignment of the type.
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Pos = LineStr.find("Alignment:");
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if (Pos != StringRef::npos) {
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// Skip past the "Alignment:" prefix.
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LineStr = LineStr.substr(Pos + strlen("Alignment:"));
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unsigned long long Alignment = 0;
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if (parseUnsigned(LineStr, Alignment))
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CurrentLayout.Align = Alignment;
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continue;
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}
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// Check for the size/alignment of the type. The number follows "size=" or
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// "align=" indicates number of bytes.
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Pos = LineStr.find("sizeof=");
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if (Pos != StringRef::npos) {
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/* Skip past the sizeof= prefix. */
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LineStr = LineStr.substr(Pos + strlen("sizeof="));
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// Parse size.
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unsigned long long Size = 0;
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if (parseUnsigned(LineStr, Size))
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CurrentLayout.Size = Size * 8;
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Pos = LineStr.find("align=");
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if (Pos != StringRef::npos) {
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/* Skip past the align= prefix. */
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LineStr = LineStr.substr(Pos + strlen("align="));
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// Parse alignment.
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unsigned long long Alignment = 0;
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if (parseUnsigned(LineStr, Alignment))
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CurrentLayout.Align = Alignment * 8;
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}
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continue;
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}
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// Check for the field offsets of the type.
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Pos = LineStr.find("FieldOffsets: [");
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if (Pos != StringRef::npos) {
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LineStr = LineStr.substr(Pos + strlen("FieldOffsets: ["));
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while (!LineStr.empty() && isDigit(LineStr[0])) {
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unsigned long long Offset = 0;
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if (parseUnsigned(LineStr, Offset))
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CurrentLayout.FieldOffsets.push_back(Offset);
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// Skip over this offset, the following comma, and any spaces.
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LineStr = LineStr.substr(1);
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LineStr = LineStr.drop_while(isWhitespace);
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}
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}
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// Check for the virtual base offsets.
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Pos = LineStr.find("VBaseOffsets: [");
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if (Pos != StringRef::npos) {
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LineStr = LineStr.substr(Pos + strlen("VBaseOffsets: ["));
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while (!LineStr.empty() && isDigit(LineStr[0])) {
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unsigned long long Offset = 0;
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if (parseUnsigned(LineStr, Offset))
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CurrentLayout.VBaseOffsets.push_back(CharUnits::fromQuantity(Offset));
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// Skip over this offset, the following comma, and any spaces.
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LineStr = LineStr.substr(1);
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LineStr = LineStr.drop_while(isWhitespace);
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}
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continue;
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}
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// Check for the base offsets.
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Pos = LineStr.find("BaseOffsets: [");
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if (Pos != StringRef::npos) {
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LineStr = LineStr.substr(Pos + strlen("BaseOffsets: ["));
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while (!LineStr.empty() && isDigit(LineStr[0])) {
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unsigned long long Offset = 0;
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if (parseUnsigned(LineStr, Offset))
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CurrentLayout.BaseOffsets.push_back(CharUnits::fromQuantity(Offset));
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// Skip over this offset, the following comma, and any spaces.
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LineStr = LineStr.substr(1);
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LineStr = LineStr.drop_while(isWhitespace);
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}
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}
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}
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// Flush the last type/layout, if there is one.
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if (!CurrentType.empty())
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Layouts[CurrentType] = CurrentLayout;
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}
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bool
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LayoutOverrideSource::layoutRecordType(const RecordDecl *Record,
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uint64_t &Size, uint64_t &Alignment,
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llvm::DenseMap<const FieldDecl *, uint64_t> &FieldOffsets,
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llvm::DenseMap<const CXXRecordDecl *, CharUnits> &BaseOffsets,
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llvm::DenseMap<const CXXRecordDecl *, CharUnits> &VirtualBaseOffsets)
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{
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// We can't override unnamed declarations.
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if (!Record->getIdentifier())
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return false;
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// Check whether we have a layout for this record.
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llvm::StringMap<Layout>::iterator Known = Layouts.find(Record->getName());
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if (Known == Layouts.end())
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return false;
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// Provide field layouts.
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unsigned NumFields = 0;
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for (RecordDecl::field_iterator F = Record->field_begin(),
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FEnd = Record->field_end();
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F != FEnd; ++F, ++NumFields) {
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if (NumFields >= Known->second.FieldOffsets.size())
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continue;
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FieldOffsets[*F] = Known->second.FieldOffsets[NumFields];
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}
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// Wrong number of fields.
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if (NumFields != Known->second.FieldOffsets.size())
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return false;
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// Provide base offsets.
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if (const auto *RD = dyn_cast<CXXRecordDecl>(Record)) {
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unsigned NumNB = 0;
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unsigned NumVB = 0;
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for (const auto &I : RD->vbases()) {
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if (NumVB >= Known->second.VBaseOffsets.size())
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continue;
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const CXXRecordDecl *VBase = I.getType()->getAsCXXRecordDecl();
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VirtualBaseOffsets[VBase] = Known->second.VBaseOffsets[NumVB++];
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}
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for (const auto &I : RD->bases()) {
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if (I.isVirtual() || NumNB >= Known->second.BaseOffsets.size())
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continue;
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const CXXRecordDecl *Base = I.getType()->getAsCXXRecordDecl();
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BaseOffsets[Base] = Known->second.BaseOffsets[NumNB++];
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}
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}
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Size = Known->second.Size;
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Alignment = Known->second.Align;
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return true;
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}
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LLVM_DUMP_METHOD void LayoutOverrideSource::dump() {
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raw_ostream &OS = llvm::errs();
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for (llvm::StringMap<Layout>::iterator L = Layouts.begin(),
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LEnd = Layouts.end();
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L != LEnd; ++L) {
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OS << "Type: blah " << L->first() << '\n';
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OS << " Size:" << L->second.Size << '\n';
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OS << " Alignment:" << L->second.Align << '\n';
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OS << " FieldOffsets: [";
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for (unsigned I = 0, N = L->second.FieldOffsets.size(); I != N; ++I) {
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if (I)
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OS << ", ";
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OS << L->second.FieldOffsets[I];
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}
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OS << "]\n";
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}
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}
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