use mem-mapping on Windows

src/coreclr/inc/pedecoder.inl

@@ -100,7 +100,6 @@ inline PEDecoder::PEDecoder(PTR_VOID mappedBase, bool fixedUp /*= FALSE*/)
     {
         CONSTRUCTOR_CHECK;
         PRECONDITION(CheckPointer(mappedBase));
-        PRECONDITION(CheckAligned(mappedBase, GetOsPageSize()));
         PRECONDITION(PEDecoder(mappedBase,fixedUp).CheckNTHeaders());
         THROWS;
         GC_NOTRIGGER;
@@ -172,7 +171,6 @@ inline HRESULT PEDecoder::Init(void *mappedBase, bool fixedUp /*= FALSE*/)
         NOTHROW;
         GC_NOTRIGGER;
         PRECONDITION(CheckPointer(mappedBase));
-        PRECONDITION(CheckAligned(mappedBase, GetOsPageSize()));
         PRECONDITION(!HasContents());
     }
     CONTRACTL_END;

src/coreclr/pal/src/map/map.cpp

@@ -2165,14 +2165,9 @@ void * MAPMapPEFile(HANDLE hFile, off_t offset)
         goto done;
     }
 
-    // For compat reasons we always allow 32bit header.
-    // We may not get correct preferred ImageBase, but otherwise 32bit header is the same for our uses here.
-    // We will not patch the header into platform bitness though, since coreclr does not require that.
-    // NOTE: actual checks whether the PE is platform-specific or contains native code will happen later as needed.
     if ((VAL16(IMAGE_DOS_SIGNATURE) != VAL16(dosHeader.e_magic))
         || (VAL32(IMAGE_NT_SIGNATURE) != VAL32(ntHeader.Signature))
-        || ((VAL16(IMAGE_NT_OPTIONAL_HDR_MAGIC) != VAL16(ntHeader.OptionalHeader.Magic)) &&
-            (VAL16(IMAGE_NT_OPTIONAL_HDR32_MAGIC) != VAL16(ntHeader.OptionalHeader.Magic))))
+        || (VAL16(IMAGE_NT_OPTIONAL_HDR_MAGIC) != VAL16(ntHeader.OptionalHeader.Magic) ) )
     {
         ERROR_(LOADER)( "Magic number mismatch\n" );
         palError = ERROR_INVALID_PARAMETER;

src/coreclr/tools/aot/ILCompiler.ReadyToRun/ObjectWriter/R2RPEBuilder.cs

@@ -683,17 +683,25 @@ public static PEHeaderBuilder Create(Subsystem subsystem, TargetDetails target)
             ulong imageBase = is64BitTarget ? PE64HeaderConstants.DllImageBase : PE32HeaderConstants.ImageBase;
 
             int fileAlignment = 0x200;
-            if (!target.IsWindows && !is64BitTarget)
+            if (target.IsWindows || !is64BitTarget)
             {
                 // To minimize wasted VA space on 32-bit systems, align file to page boundaries (presumed to be 4K)
+                //
+                // On Windows we use 4K file alignment, so that we could load the PE manually, if needed, using
+                // placeholdr APIs (MapViewOfFile3, etc), which have 4K granularity.
                 fileAlignment = 0x1000;
             }
 
             int sectionAlignment = 0x1000;
             if (!target.IsWindows && is64BitTarget)
             {
-                // On Linux, we must match the bottom 12 bits of section RVA's to their file offsets. For this reason
+                // On 64bit Linux, we must match the bottom 12 bits of section RVA's to their file offsets. For this reason
                 // we need the same alignment for both.
+                //
+                // In addition to that we specify section RVAs to be at least 64K apart, which is > page on most systems.
+                // It ensures that the sections will not overlap when mapped from a singlefile bundle, which introduces a sub-page skew.
+                //
+                // Such format would not be accepted by OS loader on Windows, but it is not a problem on Unix.
                 sectionAlignment = fileAlignment;
             }
 

src/coreclr/utilcode/pedecoder.cpp

@@ -372,7 +372,7 @@ CHECK PEDecoder::CheckSection(COUNT_T previousAddressEnd, COUNT_T addressStart,
         CHECK(alignedSize >= VAL32(pNT->OptionalHeader.SizeOfImage));
 
     // Check expected alignments
-    CHECK(CheckAligned(addressStart, VAL32(pNT->OptionalHeader.SectionAlignment)));
+    // CHECK(CheckAligned(addressStart, VAL32(pNT->OptionalHeader.SectionAlignment)));
     CHECK(CheckAligned(offsetStart, VAL32(pNT->OptionalHeader.FileAlignment)));
     CHECK(CheckAligned(offsetSize, VAL32(pNT->OptionalHeader.FileAlignment)));
 

src/coreclr/vm/assembly.cpp

@@ -208,17 +208,6 @@ void Assembly::Init(AllocMemTracker *pamTracker, LoaderAllocator *pLoaderAllocat
     //  loading it entirely.
     //CacheFriendAssemblyInfo();
 
-    if (IsCollectible())
-    {
-        COUNT_T size;
-        BYTE *start = (BYTE*)m_pManifest->GetPEAssembly()->GetLoadedImageContents(&size);
-        if (start != NULL)
-        {
-            GCX_COOP();
-            LoaderAllocator::AssociateMemoryWithLoaderAllocator(start, start + size, m_pLoaderAllocator);
-        }
-    }
-
     {
         CANNOTTHROWCOMPLUSEXCEPTION();
         FAULT_FORBID();
@@ -230,6 +219,20 @@ void Assembly::Init(AllocMemTracker *pamTracker, LoaderAllocator *pLoaderAllocat
     }
 }
 
+void Assembly::AssociateMemoryIfCollectible()
+{
+    if (IsCollectible())
+    {
+        COUNT_T size;
+        BYTE* start = (BYTE*)m_pManifest->GetPEAssembly()->GetLoadedImageContents(&size);
+        if (start != NULL)
+        {
+            GCX_COOP();
+            LoaderAllocator::AssociateMemoryWithLoaderAllocator(start, start + size, m_pLoaderAllocator);
+        }
+    }
+}
+
 Assembly::~Assembly()
 {
     CONTRACTL

src/coreclr/vm/assembly.hpp

@@ -81,6 +81,7 @@ class Assembly
 public:
     Assembly(BaseDomain *pDomain, PEAssembly *pPEAssembly, DebuggerAssemblyControlFlags debuggerFlags, BOOL fIsCollectible);
     void Init(AllocMemTracker *pamTracker, LoaderAllocator *pLoaderAllocator);
+    void AssociateMemoryIfCollectible();
 
     void StartUnload();
     void Terminate( BOOL signalProfiler = TRUE );

src/coreclr/vm/domainfile.cpp

@@ -526,6 +526,7 @@ void DomainFile::LoadLibrary()
     CONTRACTL_END;
 
     GetPEAssembly()->EnsureLoaded();
+    ((DomainAssembly*)this)->GetAssembly()->AssociateMemoryIfCollectible();
 }
 
 void DomainFile::PostLoadLibrary()

src/coreclr/vm/peimage.cpp

@@ -814,13 +814,6 @@ PTR_PEImageLayout PEImage::GetOrCreateLayoutInternal(DWORD imageLayoutMask)
 
     if (pRetVal==NULL)
     {
-        // no-path layouts are filled up at creation, if image format permits.
-        if (!HasPath())
-        {
-            // TODO: VS we should manually map flat layouts for R2R here.
-            ThrowHR(COR_E_BADIMAGEFORMAT);
-        }
-
         BOOL bIsLoadedLayoutSuitable = ((imageLayoutMask & PEImageLayout::LAYOUT_LOADED) != 0);
         BOOL bIsFlatLayoutSuitable = ((imageLayoutMask & PEImageLayout::LAYOUT_FLAT) != 0);
 
@@ -862,7 +855,6 @@ PTR_PEImageLayout PEImage::CreateLoadedLayout(bool throwOnFailure)
         GC_TRIGGERS;
         MODE_ANY;
         PRECONDITION(m_pLayoutLock->IsWriterLock());
-        PRECONDITION(IsFile());
     }
     CONTRACTL_END;
 
@@ -901,17 +893,6 @@ PTR_PEImageLayout PEImage::CreateFlatLayout()
 
     PTR_PEImageLayout pFlatLayout = PEImageLayout::LoadFlat(this);
     SetLayout(IMAGE_FLAT, pFlatLayout);
-
-    if (m_pLayouts[IMAGE_LOADED] == NULL &&
-        pFlatLayout->CheckNTHeaders() &&
-        pFlatLayout->CheckILOnly() &&
-        !pFlatLayout->HasWriteableSections() &&
-        !pFlatLayout->HasReadyToRunHeader())
-    {
-        pFlatLayout->AddRef();
-        SetLayout(IMAGE_LOADED, pFlatLayout);
-    }
-
     return pFlatLayout;
 }
 
@@ -930,16 +911,6 @@ PTR_PEImage PEImage::CreateFromByteArray(const BYTE* array, COUNT_T size)
 
     SimpleWriteLockHolder lock(pImage->m_pLayoutLock);
     pImage->SetLayout(IMAGE_FLAT,pLayout);
-
-    // TODO: VS allow R2R for now, meaning it will run as IL-only
-    if (pLayout->CheckNTHeaders() &&
-        pLayout->CheckILOnly() &&
-        !pLayout->HasWriteableSections())
-    {
-        pLayout->AddRef();
-        pImage->SetLayout(IMAGE_LOADED, pLayout);
-    }
-
     RETURN dac_cast<PTR_PEImage>(pImage.Extract());
 }
 
@@ -996,7 +967,12 @@ HANDLE PEImage::GetFileHandle()
     {
         ErrorModeHolder mode(SEM_NOOPENFILEERRORBOX|SEM_FAILCRITICALERRORS);
         m_hFile=WszCreateFile((LPCWSTR) GetPathToLoad(),
-                               GENERIC_READ,
+                               GENERIC_READ
+#if TARGET_WINDOWS
+                                   // the file may have native code sections, make sure we have execute permissions
+                                   | GENERIC_EXECUTE
+#endif
+                               ,
                                FILE_SHARE_READ|FILE_SHARE_DELETE,
                                NULL,
                                OPEN_EXISTING,
@@ -1027,7 +1003,12 @@ HRESULT PEImage::TryOpenFile()
     {
         ErrorModeHolder mode(SEM_NOOPENFILEERRORBOX | SEM_FAILCRITICALERRORS);
         m_hFile=WszCreateFile((LPCWSTR)GetPathToLoad(),
-                              GENERIC_READ,
+                              GENERIC_READ
+#if TARGET_WINDOWS
+                                  // the file may have native code sections, make sure we have execute permissions
+                                  | GENERIC_EXECUTE
+#endif
+                              ,
                               FILE_SHARE_READ|FILE_SHARE_DELETE,
                               NULL,
                               OPEN_EXISTING,

src/coreclr/vm/peimage.h

@@ -91,6 +91,7 @@ class PEImage final
 
     BOOL HasLoadedLayout();
     PTR_PEImageLayout GetLoadedLayout();
+    PTR_PEImageLayout GetFlatLayout();
 
     BOOL  HasPath();
     ULONG GetPathHash();

src/coreclr/vm/peimage.inl

@@ -150,6 +150,15 @@ inline PTR_PEImageLayout PEImage::GetLoadedLayout()
     return m_pLayouts[IMAGE_LOADED];
 }
 
+inline PTR_PEImageLayout PEImage::GetFlatLayout()
+{
+    LIMITED_METHOD_CONTRACT;
+    SUPPORTS_DAC;
+
+    _ASSERTE(m_pLayouts[IMAGE_FLAT] != NULL);
+    return m_pLayouts[IMAGE_FLAT];
+}
+
 inline BOOL PEImage::IsOpened()
 {
     LIMITED_METHOD_CONTRACT;