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Logic to load R2R files on WebAssembly #127229

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19 changes: 17 additions & 2 deletions src/coreclr/hosts/corerun/wasm/libCorerun.js
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Original file line number Diff line number Diff line change
Expand Up @@ -178,7 +178,15 @@ function libCoreRunFactory() {
} catch (e) {
return false;
}
const wasmModule = new WebAssembly.Module(wasmBytes);
let wasmModule;
try {
wasmModule = new WebAssembly.Module(wasmBytes);
} catch (e) {
const errormessage = e instanceof Error ? e.message : String(e);
console.error("Failed to compile WebAssembly module for Webcil image:", {wasmPath, errormessage});
Comment on lines +185 to +186
return false;
}

const tableStartIndex = wasmTable.length;

var payloadSize = 0;
Expand All @@ -195,7 +203,14 @@ function libCoreRunFactory() {
console.error("Webcil payload size is 0; cannot load image");
return false;
}
wasmTable.grow(tableSize);

try {
wasmTable.grow(tableSize);
} catch (e) {
const errormessage = e instanceof Error ? e.message : String(e);
console.error("Failed to grow WebAssembly table for Webcil image:", {wasmPath, errormessage});
return false;
}

var payloadPtr = 0;
var wasmInstance;
Expand Down
27 changes: 20 additions & 7 deletions src/coreclr/inc/webcildecoder.h
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Expand Up @@ -197,15 +197,26 @@ class WebcilDecoder
void *GetNativeEntryPoint() const { return NULL; }

// ------------------------------------------------------------
// R2R — not supported for Webcil
// R2R
// ------------------------------------------------------------

BOOL HasReadyToRunHeader() const { return FALSE; }
BOOL HasReadyToRunHeader() const;
BOOL IsComponentAssembly() const { return FALSE; }
READYTORUN_HEADER *GetReadyToRunHeader() const { return NULL; }
BOOL IsNativeMachineFormat() const { return FALSE; }
PTR_CVOID GetNativeManifestMetadata(COUNT_T *pSize = NULL) const;
READYTORUN_HEADER *GetReadyToRunHeader() const;
BOOL IsNativeMachineFormat() const { return TRUE; }
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@pavelsavara pavelsavara Apr 21, 2026

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TRUE only when you found R2R ?

PTR_CVOID GetNativeManifestMetadata(COUNT_T *pSize) const;

CHECK CheckDirectory(IMAGE_DATA_DIRECTORY *pDir, int forbiddenFlags = 0, IsNullOK ok = NULL_NOT_OK) const;
TADDR GetDirectoryData(IMAGE_DATA_DIRECTORY *pDir) const;
SSIZE_T GetTableBaseOffset() const
{
if (m_pHeader == NULL)
return 0;
return m_pHeader->VersionMajor >= WEBCIL_VERSION_MAJOR_1 ? ((const WebcilHeader_1 *)m_pHeader)->TableBase : 0;
}
private:
READYTORUN_HEADER *FindReadyToRunHeader() const;
public:
// ------------------------------------------------------------
// RVA operations (remaining private)
// ------------------------------------------------------------
Expand Down Expand Up @@ -274,12 +285,14 @@ class WebcilDecoder
// Instance members
TADDR m_base;
COUNT_T m_size;
BOOL m_hasContents;
BOOL m_relocated = FALSE;
bool m_relocated = FALSE;
bool m_hasContents;
mutable bool m_hasNoReadyToRunHeader;
const WebcilHeader *m_pHeader;
const WebcilSectionHeader *m_sections;

mutable IMAGE_COR20_HEADER *m_pCorHeader;
mutable PTR_READYTORUN_HEADER m_pReadyToRunHeader;
};

#endif // FEATURE_WEBCIL
Expand Down
17 changes: 12 additions & 5 deletions ...ILCompiler.ReadyToRun/Compiler/DependencyAnalysis/ReadyToRun/RuntimeFunctionsTableNode.cs
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Original file line number Diff line number Diff line change
Expand Up @@ -124,12 +124,19 @@ public override ObjectData GetData(NodeFactory factory, bool relocsOnly = false)
symbol = method;
}

runtimeFunctionsBuilder.EmitReloc(symbol, RelocType.IMAGE_REL_BASED_ADDR32NB, delta: frameInfo.StartOffset + _nodeFactory.Target.CodeDelta);
if (!relocsOnly && _nodeFactory.Target.Architecture == TargetArchitecture.X64)
if (_nodeFactory.Target.Architecture == TargetArchitecture.Wasm32)
{
// On Amd64, the 2nd word contains the EndOffset of the runtime function
Debug.Assert(frameInfo.StartOffset != frameInfo.EndOffset);
runtimeFunctionsBuilder.EmitReloc(symbol, RelocType.IMAGE_REL_BASED_ADDR32NB, delta: frameInfo.EndOffset);
runtimeFunctionsBuilder.EmitReloc(symbol, RelocType.WASM_TABLE_INDEX_I32, frameIndex);
}
else
{
runtimeFunctionsBuilder.EmitReloc(symbol, RelocType.IMAGE_REL_BASED_ADDR32NB, delta: frameInfo.StartOffset + _nodeFactory.Target.CodeDelta);
if (!relocsOnly && _nodeFactory.Target.Architecture == TargetArchitecture.X64)
{
// On Amd64, the 2nd word contains the EndOffset of the runtime function
Debug.Assert(frameInfo.StartOffset != frameInfo.EndOffset);
runtimeFunctionsBuilder.EmitReloc(symbol, RelocType.IMAGE_REL_BASED_ADDR32NB, delta: frameInfo.EndOffset);
}
}
Comment on lines +127 to 140
runtimeFunctionsBuilder.EmitReloc(factory.RuntimeFunctionsGCInfo, RelocType.IMAGE_REL_BASED_ADDR32NB, funcletOffsets[frameIndex]);
runtimeFunctionIndex++;
Expand Down
172 changes: 160 additions & 12 deletions src/coreclr/utilcode/webcildecoder.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -34,10 +34,12 @@ bool WebcilDecoder::DetectWebcilFormat(const void* data, COUNT_T size)
WebcilDecoder::WebcilDecoder()
: m_base(0),
m_size(0),
m_hasContents(FALSE),
m_hasContents(false),
m_hasNoReadyToRunHeader(false),
m_pHeader(NULL),
m_sections(NULL),
m_pCorHeader(NULL)
m_pCorHeader(NULL),
m_pReadyToRunHeader(NULL)
{
LIMITED_METHOD_CONTRACT;
}
Expand Down Expand Up @@ -82,7 +84,7 @@ void WebcilDecoder::Reset()
LIMITED_METHOD_CONTRACT;
m_base = 0;
m_size = 0;
m_hasContents = FALSE;
m_hasContents = false;
m_pHeader = NULL;
m_sections = NULL;
m_pCorHeader = NULL;
Expand Down Expand Up @@ -470,14 +472,6 @@ ULONG WebcilDecoder::GetEntryPointToken() const
// R2R / native manifest metadata
// ------------------------------------------------------------

PTR_CVOID WebcilDecoder::GetNativeManifestMetadata(COUNT_T *pSize) const
{
LIMITED_METHOD_CONTRACT;
if (pSize != NULL)
*pSize = 0;
return NULL;
}

// ------------------------------------------------------------
// RVA operations
// ------------------------------------------------------------
Expand Down Expand Up @@ -864,7 +858,7 @@ TADDR WebcilDecoder::GetDirectoryEntryData(int entry, COUNT_T *pSize) const
return (TADDR)0;
}

const WebcilSectionHeader *sections = (const WebcilSectionHeader *)(m_base + sizeof(WebcilHeader));
const WebcilSectionHeader *sections = m_sections;
const WebcilSectionHeader *relocSection = &sections[sectionIndex];

if (pSize != NULL)
Expand Down Expand Up @@ -916,6 +910,160 @@ CHECK WebcilDecoder::CheckILMethod(RVA rva)
return CorDecoderHelpers::CheckILMethod(*this, rva);
}

BOOL WebcilDecoder::HasReadyToRunHeader() const
{
CONTRACTL
{
INSTANCE_CHECK;
NOTHROW;
GC_NOTRIGGER;
CANNOT_TAKE_LOCK;
SUPPORTS_DAC;
}
CONTRACTL_END;

if (m_hasNoReadyToRunHeader)
return FALSE;

if (m_pReadyToRunHeader != NULL)
return TRUE;

return FindReadyToRunHeader() != NULL;
}

READYTORUN_HEADER * WebcilDecoder::GetReadyToRunHeader() const
{
CONTRACT(READYTORUN_HEADER *)
{
INSTANCE_CHECK;
PRECONDITION(CheckNTHeaders());
PRECONDITION(HasCorHeader());
PRECONDITION(HasReadyToRunHeader());
NOTHROW;
GC_NOTRIGGER;
Comment on lines +934 to +943
POSTCONDITION(CheckPointer(RETVAL));
SUPPORTS_DAC;
CANNOT_TAKE_LOCK;
}
CONTRACT_END;

if (m_pReadyToRunHeader != NULL)
RETURN m_pReadyToRunHeader;

RETURN FindReadyToRunHeader();
}

PTR_CVOID WebcilDecoder::GetNativeManifestMetadata(COUNT_T *pSize) const
{
CONTRACT(PTR_CVOID)
{
INSTANCE_CHECK;
PRECONDITION(HasReadyToRunHeader());
POSTCONDITION(CheckPointer(RETVAL, NULL_OK)); // TBD - may not store metadata for IJW
NOTHROW;
GC_NOTRIGGER;
}
CONTRACT_END;

IMAGE_DATA_DIRECTORY *pDir = NULL;
{
READYTORUN_HEADER * pHeader = GetReadyToRunHeader();

PTR_READYTORUN_SECTION pSections = dac_cast<PTR_READYTORUN_SECTION>(dac_cast<TADDR>(pHeader) + sizeof(READYTORUN_HEADER));
for (DWORD i = 0; i < pHeader->CoreHeader.NumberOfSections; i++)
{
// Verify that section types are sorted
_ASSERTE(i == 0 || (pSections[i - 1].Type < pSections[i].Type));

READYTORUN_SECTION * pSection = pSections + i;
if (pSection->Type == ReadyToRunSectionType::ManifestMetadata)
{
// Set pDir to the address of the manifest metadata section
pDir = &pSection->Section;
break;
}
}

// ReadyToRun file without large version bubble support doesn't have the ManifestMetadata
if (pDir == NULL)
{
if (pSize != NULL)
{
*pSize = 0;
}

RETURN NULL;
}
}

if (pSize != NULL)
*pSize = VAL32(pDir->Size);

RETURN dac_cast<PTR_VOID>(GetDirectoryData(pDir));
}

READYTORUN_HEADER * WebcilDecoder::FindReadyToRunHeader() const
{
CONTRACTL
{
NOTHROW;
GC_NOTRIGGER;
SUPPORTS_DAC;
}
CONTRACTL_END;

IMAGE_DATA_DIRECTORY *pDir = &GetCorHeader()->ManagedNativeHeader;

if (VAL32(pDir->Size) >= sizeof(READYTORUN_HEADER) && CheckDirectory(pDir))
{
PTR_READYTORUN_HEADER pHeader = PTR_READYTORUN_HEADER((TADDR)GetDirectoryData(pDir));
if (pHeader->Signature == READYTORUN_SIGNATURE)
{
m_pReadyToRunHeader = pHeader;
return pHeader;
}
}

m_hasNoReadyToRunHeader = true;
return NULL;
}

TADDR WebcilDecoder::GetDirectoryData(IMAGE_DATA_DIRECTORY *pDir) const
{
CONTRACT(TADDR)
{
INSTANCE_CHECK;
PRECONDITION(CheckNTHeaders());
PRECONDITION(CheckDirectory(pDir, 0, NULL_OK));
NOTHROW;
GC_NOTRIGGER;
SUPPORTS_DAC;
POSTCONDITION(CheckPointer((void *)RETVAL, NULL_OK));
CANNOT_TAKE_LOCK;
}
CONTRACT_END;

RETURN GetRvaData(VAL32(pDir->VirtualAddress));
}

CHECK WebcilDecoder::CheckDirectory(IMAGE_DATA_DIRECTORY *pDir, int forbiddenFlags, IsNullOK ok) const
{
CONTRACT_CHECK
{
INSTANCE_CHECK;
PRECONDITION(CheckNTHeaders());
PRECONDITION(CheckPointer(pDir));
NOTHROW;
Comment on lines +1031 to +1056
GC_NOTRIGGER;
SUPPORTS_DAC;
}
CONTRACT_CHECK_END;

CHECK(CheckRva(VAL32(pDir->VirtualAddress), VAL32(pDir->Size), forbiddenFlags, ok));

CHECK_OK;
}

// ------------------------------------------------------------
// DAC support
// ------------------------------------------------------------
Expand Down
20 changes: 18 additions & 2 deletions src/coreclr/vm/peimagelayout.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -210,6 +210,8 @@ void PEImageLayout::InitDecoders(void* data, COUNT_T size)
{
m_format = FORMAT_WEBCIL;
m_webcilDecoder.Init(data, size);
if (HasBaseRelocations())
ApplyBaseRelocations(true);
m_peDecoder.Init(data, size); // Initialize base/size/flags for cDAC
}
else
Expand Down Expand Up @@ -245,7 +247,7 @@ void PEImageLayout::ApplyBaseRelocations(bool relocationMustWriteCopy)
SSIZE_T delta = (SIZE_T) GetBase() - (SIZE_T) GetPreferredBase();

#ifdef FEATURE_WEBCIL
SSIZE_T tableBaseDelta = m_tableBaseOffset;
SSIZE_T tableBaseDelta = GetTableBaseOffset();
#endif // FEATURE_WEBCIL

// Nothing to do - image is loaded at preferred base and no table base offset
Expand Down Expand Up @@ -275,12 +277,26 @@ void PEImageLayout::ApplyBaseRelocations(bool relocationMustWriteCopy)
const SIZE_T cbPageSize = 4096;

COUNT_T dirPos = 0;
#ifdef TARGET_WASM
// WASM will padd out the reloc size to the next 16 byte boundary, so we need to validate we can safely read the IMAGE_BASE_RELOCATION struct before processing each entry.
while (dirPos < (dirSize - sizeof(IMAGE_BASE_RELOCATION)))
#else
while (dirPos < dirSize)
#endif
Comment on lines 279 to +285
{
PIMAGE_BASE_RELOCATION r = (PIMAGE_BASE_RELOCATION)(dir + dirPos);

COUNT_T fixupsSize = VAL32(r->SizeOfBlock);

#ifdef TARGET_WASM
if (fixupsSize == 0)
{
// Since WASM will pad the reloc block to the next 16 byte boundary with 0's we need to allow for a SizeOfBlock being zero.
// This can only happen for the last block in the relocation list, so we can break here instead of continue.
break;
}
#endif

USHORT *fixups = (USHORT *) (r + 1);

_ASSERTE(fixupsSize > sizeof(IMAGE_BASE_RELOCATION));
Expand Down Expand Up @@ -415,7 +431,7 @@ void PEImageLayout::ApplyBaseRelocations(bool relocationMustWriteCopy)

dirPos += fixupsSize;
}
_ASSERTE(dirSize == dirPos);
_ASSERTE(dirSize == dirPos || !IsPEFormat());

if (dwOldProtection != 0)
{
Expand Down
4 changes: 1 addition & 3 deletions src/coreclr/vm/peimagelayout.h
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Original file line number Diff line number Diff line change
Expand Up @@ -77,9 +77,7 @@ class PEImageLayout
void ApplyBaseRelocations(bool relocationMustWriteCopy);

#ifdef FEATURE_WEBCIL
// TODO-WASM: These can be removed very soon, and we can fetch this from the webcil header itself
void SetTableBaseOffset(SSIZE_T tableBaseOffset) { m_tableBaseOffset = tableBaseOffset; }
SSIZE_T GetTableBaseOffset() const { return m_tableBaseOffset; }
SSIZE_T GetTableBaseOffset() const;
#endif

// ------------------------------------------------------------
Expand Down
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