Revert "[Clang][MS] Remove assertion on BaseOffset can't be smaller than Size."

This reverts commit 5d54213.

Breaks check-clang on Windows, see https://reviews.llvm.org/D152472#4422913

Author: nico

clang/include/clang/Frontend/LayoutOverrideSource.h

@@ -30,12 +30,6 @@ namespace clang {
       /// The alignment of the record.
       uint64_t Align;
 
-      /// The offsets of non-virtual base classes in the record.
-      SmallVector<CharUnits, 8> BaseOffsets;
-
-      /// The offsets of virtual base classes in the record.
-      SmallVector<CharUnits, 8> VBaseOffsets;
-
       /// The offsets of the fields, in source order.
       SmallVector<uint64_t, 8> FieldOffsets;
     };

clang/lib/AST/RecordLayoutBuilder.cpp

@@ -2926,7 +2926,8 @@ void MicrosoftRecordLayoutBuilder::layoutNonVirtualBase(
   bool FoundBase = false;
   if (UseExternalLayout) {
     FoundBase = External.getExternalNVBaseOffset(BaseDecl, BaseOffset);
-    if (BaseOffset > Size) {
+    if (FoundBase) {
+      assert(BaseOffset >= Size && "base offset already allocated");
       Size = BaseOffset;
     }
   }
@@ -3722,28 +3723,6 @@ void ASTContext::DumpRecordLayout(const RecordDecl *RD, raw_ostream &OS,
   if (Target->defaultsToAIXPowerAlignment())
     OS << "  PreferredAlignment:" << toBits(Info.getPreferredAlignment())
        << "\n";
-  if (const CXXRecordDecl *CXXRD = dyn_cast<CXXRecordDecl>(RD)) {
-    OS << "  BaseOffsets: [";
-    const CXXRecordDecl *Base = nullptr;
-    for (auto I : CXXRD->bases()) {
-      if (I.isVirtual())
-        continue;
-      if (Base)
-        OS << ", ";
-      Base = I.getType()->getAsCXXRecordDecl();
-      OS << Info.CXXInfo->BaseOffsets[Base].getQuantity();
-    }
-    OS << "]>\n";
-    OS << "  VBaseOffsets: [";
-    const CXXRecordDecl *VBase = nullptr;
-    for (auto I : CXXRD->vbases()) {
-      if (VBase)
-        OS << ", ";
-      VBase = I.getType()->getAsCXXRecordDecl();
-      OS << Info.CXXInfo->VBaseOffsets[VBase].VBaseOffset.getQuantity();
-    }
-    OS << "]>\n";
-  }
   OS << "  FieldOffsets: [";
   for (unsigned i = 0, e = Info.getFieldCount(); i != e; ++i) {
     if (i)

clang/lib/Frontend/LayoutOverrideSource.cpp

@@ -7,7 +7,6 @@
 //===----------------------------------------------------------------------===//
 #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>
@@ -27,18 +26,6 @@ static std::string parseName(StringRef S) {
   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())
@@ -93,8 +80,8 @@ LayoutOverrideSource::LayoutOverrideSource(StringRef Filename) {
       LineStr = LineStr.substr(Pos + strlen(" Size:"));
 
       unsigned long long Size = 0;
-      if (parseUnsigned(LineStr, Size))
-        CurrentLayout.Size = Size;
+      (void)LineStr.getAsInteger(10, Size);
+      CurrentLayout.Size = Size;
       continue;
     }
 
@@ -105,22 +92,21 @@ LayoutOverrideSource::LayoutOverrideSource(StringRef Filename) {
       LineStr = LineStr.substr(Pos + strlen("Alignment:"));
 
       unsigned long long Alignment = 0;
-      if (parseUnsigned(LineStr, Alignment))
-        CurrentLayout.Align = Alignment;
+      (void)LineStr.getAsInteger(10, Alignment);
+      CurrentLayout.Align = Alignment;
       continue;
     }
 
-    // Check for the size/alignment of the type. The number follows "size=" or
-    // "align=" indicates number of bytes.
+    // Check for the size/alignment of the type.
     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;
+      (void)LineStr.getAsInteger(10, Size);
+      CurrentLayout.Size = Size;
 
       Pos = LineStr.find("align=");
       if (Pos != StringRef::npos) {
@@ -129,59 +115,34 @@ LayoutOverrideSource::LayoutOverrideSource(StringRef Filename) {
 
         // Parse alignment.
         unsigned long long Alignment = 0;
-        if (parseUnsigned(LineStr, Alignment))
-          CurrentLayout.Align = Alignment * 8;
+        (void)LineStr.getAsInteger(10, Alignment);
+        CurrentLayout.Align = Alignment;
       }
 
       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);
-      }
-    }
+    if (Pos == StringRef::npos)
+      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));
+    LineStr = LineStr.substr(Pos + strlen("FieldOffsets: ["));
+    while (!LineStr.empty() && isDigit(LineStr[0])) {
+      // Parse this offset.
+      unsigned Idx = 1;
+      while (Idx < LineStr.size() && isDigit(LineStr[Idx]))
+        ++Idx;
 
-        // Skip over this offset, the following comma, and any spaces.
-        LineStr = LineStr.substr(1);
-        while (!LineStr.empty() && isWhitespace(LineStr[0]))
-          LineStr = LineStr.substr(1);
-      }
-    }
+      unsigned long long Offset = 0;
+      (void)LineStr.substr(0, Idx).getAsInteger(10, Offset);
 
-    // 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));
+      CurrentLayout.FieldOffsets.push_back(Offset);
 
-        // Skip over this offset, the following comma, and any spaces.
+      // Skip over this offset, the following comma, and any spaces.
+      LineStr = LineStr.substr(Idx + 1);
+      while (!LineStr.empty() && isWhitespace(LineStr[0]))
         LineStr = LineStr.substr(1);
-        while (!LineStr.empty() && isWhitespace(LineStr[0]))
-          LineStr = LineStr.substr(1);
-      }
     }
   }
 
@@ -221,24 +182,6 @@ LayoutOverrideSource::layoutRecordType(const RecordDecl *Record,
   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;