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Merged
merged 4 commits into from
May 16, 2025
Merged

Add support for no GC regions in x86 GC info #115602

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7605c50
Add support for no GC regions in x86 GC info
filipnavara May 14, 2025
c2b328a
Update JIT-EE GUID
filipnavara May 15, 2025
920da2b
Revert "Update JIT-EE GUID"
filipnavara May 15, 2025
c1d9307
Disable cpObj unrolling optimization
filipnavara May 15, 2025
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12 changes: 6 additions & 6 deletions src/coreclr/System.Private.CoreLib/src/System/Runtime/ExceptionServices/AsmOffsets.cs
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Expand Up @@ -68,9 +68,9 @@ class AsmOffsets
public const int OFFSETOF__StackFrameIterator__m_isRuntimeWrappedExceptions = 0x132;
#elif TARGET_X86
public const int OFFSETOF__REGDISPLAY__m_pCurrentContext = 0x4;
public const int SIZEOF__StackFrameIterator = 0x3cc;
public const int OFFSETOF__StackFrameIterator__m_isRuntimeWrappedExceptions = 0x3ba;
public const int OFFSETOF__StackFrameIterator__m_AdjustedControlPC = 0x3c8;
public const int SIZEOF__StackFrameIterator = 0x3d4;
public const int OFFSETOF__StackFrameIterator__m_isRuntimeWrappedExceptions = 0x3c2;
public const int OFFSETOF__StackFrameIterator__m_AdjustedControlPC = 0x3d0;
#else // TARGET_64BIT
public const int OFFSETOF__REGDISPLAY__m_pCurrentContext = 0x4;
public const int SIZEOF__StackFrameIterator = 0xcc;
Expand Down Expand Up @@ -134,9 +134,9 @@ class AsmOffsets
public const int OFFSETOF__StackFrameIterator__m_isRuntimeWrappedExceptions = 0x12a;
#elif TARGET_X86
public const int OFFSETOF__REGDISPLAY__m_pCurrentContext = 0x4;
public const int SIZEOF__StackFrameIterator = 0x3c4;
public const int OFFSETOF__StackFrameIterator__m_isRuntimeWrappedExceptions = 0x3b2;
public const int OFFSETOF__StackFrameIterator__m_AdjustedControlPC = 0x3c0;
public const int SIZEOF__StackFrameIterator = 0x3cc;
public const int OFFSETOF__StackFrameIterator__m_isRuntimeWrappedExceptions = 0x3ba;
public const int OFFSETOF__StackFrameIterator__m_AdjustedControlPC = 0x3c8;
#else // TARGET_64BIT
public const int OFFSETOF__REGDISPLAY__m_pCurrentContext = 0x4;
public const int SIZEOF__StackFrameIterator = 0xc4;
Expand Down
36 changes: 36 additions & 0 deletions src/coreclr/gcdump/i386/gcdumpx86.cpp
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Expand Up @@ -114,6 +114,17 @@ size_t GCDump::DumpInfoHdr (PTR_CBYTE gcInfoBlock,
header->revPInvokeOffset = count;
}

if (header->noGCRegionCnt == HAS_NOGCREGIONS)
{
hasArgTabOffset = TRUE;
table += decodeUnsigned(table, &count);
header->noGCRegionCnt = count;
}
else if (header->noGCRegionCnt > 0)
{
hasArgTabOffset = TRUE;
}

//
// First print out all the basic information
//
Expand Down Expand Up @@ -156,6 +167,8 @@ size_t GCDump::DumpInfoHdr (PTR_CBYTE gcInfoBlock,
gcPrintf(" Sync region = [%u,%u] ([0x%x,0x%x])\n",
header->syncStartOffset, header->syncEndOffset,
header->syncStartOffset, header->syncEndOffset);
if (header->noGCRegionCnt > 0)
gcPrintf(" no GC region count = %2u \n", header->noGCRegionCnt);

if (header->epilogCount > 1 || (header->epilogCount != 0 &&
header->epilogAtEnd == 0))
Expand Down Expand Up @@ -232,6 +245,23 @@ size_t GCDump::DumpGCTable(PTR_CBYTE table,
if (header.ebxSaved) calleeSavedRegs++;
}

/* Dump the no GC region table */

if (header.noGCRegionCnt > 0)
{
count = header.noGCRegionCnt;
while (count-- > 0)
{
unsigned regionOffset;
unsigned regionSize;

table += decodeUnsigned(table, &regionOffset);
table += decodeUnsigned(table, &regionSize);

gcPrintf("[%04X-%04X) no GC region\n", regionOffset, regionOffset + regionSize);
}
}

/* Dump the untracked frame variable table */

count = header.untrackedCnt;
Expand Down Expand Up @@ -995,6 +1025,12 @@ void GCDump::DumpPtrsInFrame(PTR_CBYTE gcInfoBlock,
header.revPInvokeOffset = offset;
_ASSERTE(offset != INVALID_REV_PINVOKE_OFFSET);
}
if (header.noGCRegionCnt == HAS_NOGCREGIONS)
{
unsigned count;
table += decodeUnsigned(table, &count);
header.noGCRegionCnt = count;
}

prologSize = header.prologSize;
epilogSize = header.epilogSize;
Expand Down
6 changes: 6 additions & 0 deletions src/coreclr/inc/gc_unwind_x86.h
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Expand Up @@ -367,6 +367,8 @@ struct hdrInfo
unsigned int syncEpilogStart; // The start of the epilog. Synchronized methods are guaranteed to have no more than one epilog.
unsigned int revPInvokeOffset; // INVALID_REV_PINVOKE_OFFSET if there is no Reverse PInvoke frame

unsigned int noGCRegionCnt;

enum { NOT_IN_PROLOG = -1, NOT_IN_EPILOG = -1 };

int prologOffs; // NOT_IN_PROLOG if not in prolog
Expand Down Expand Up @@ -403,4 +405,8 @@ size_t DecodeGCHdrInfo(GCInfoToken gcInfoToken,
unsigned curOffset,
hdrInfo * infoPtr);

bool IsInNoGCRegion(hdrInfo * infoPtr,
PTR_CBYTE table,
unsigned curOffset);

#endif // _UNWIND_X86_H
27 changes: 22 additions & 5 deletions src/coreclr/inc/gcdecoder.cpp
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Expand Up @@ -205,9 +205,22 @@ PTR_CBYTE FASTCALL decodeHeader(PTR_CBYTE table, UINT32 version, InfoHdr* header
nextByte = *table++;
encoding = nextByte & ADJ_ENCODING_MAX;
// encoding here always corresponds to codes in InfoHdrAdjust2 set

_ASSERTE(encoding < SET_RET_KIND_MAX);
header->returnKind = (ReturnKind)encoding;
if (encoding <= SET_RET_KIND_MAX)
{
header->returnKind = (ReturnKind)encoding;
}
else if (encoding < FFFF_NOGCREGION_CNT)
{
header->noGCRegionCnt = encoding - SET_NOGCREGIONS_CNT;
}
else if (encoding == FFFF_NOGCREGION_CNT)
{
header->noGCRegionCnt = HAS_NOGCREGIONS;
}
else
{
_ASSERTE(!"Unexpected encoding");
}
break;
}
}
Expand Down Expand Up @@ -470,7 +483,8 @@ bool InfoHdrSmall::isHeaderMatch(const InfoHdr& target) const
target.varPtrTableSize != HAS_VARPTR &&
target.gsCookieOffset != HAS_GS_COOKIE_OFFSET &&
target.syncStartOffset != HAS_SYNC_OFFSET &&
target.revPInvokeOffset != HAS_REV_PINVOKE_FRAME_OFFSET);
target.revPInvokeOffset != HAS_REV_PINVOKE_FRAME_OFFSET &&
target.noGCRegionCnt != HAS_NOGCREGIONS);
#endif

// compare two InfoHdr's up to but not including the untrackCnt field
Expand All @@ -495,7 +509,10 @@ bool InfoHdrSmall::isHeaderMatch(const InfoHdr& target) const
if (target.syncStartOffset != INVALID_SYNC_OFFSET)
return false;

if (target.revPInvokeOffset!= INVALID_REV_PINVOKE_OFFSET)
if (target.revPInvokeOffset != INVALID_REV_PINVOKE_OFFSET)
return false;

if (target.noGCRegionCnt > 0)
return false;

return true;
Expand Down
22 changes: 18 additions & 4 deletions src/coreclr/inc/gcinfotypes.h
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Expand Up @@ -320,7 +320,8 @@ enum infoHdrAdjustConstants {
SET_EPILOGSIZE_MAX = 10, // Change to 6
SET_EPILOGCNT_MAX = 4,
SET_UNTRACKED_MAX = 3,
SET_RET_KIND_MAX = 4, // 2 bits for ReturnKind
SET_RET_KIND_MAX = 3, // 2 bits for ReturnKind
SET_NOGCREGIONS_MAX = 4,
ADJ_ENCODING_MAX = 0x7f, // Maximum valid encoding in a byte
// Also used to mask off next bit from each encoding byte.
MORE_BYTES_TO_FOLLOW = 0x80 // If the High-bit of a header or adjustment byte
Expand Down Expand Up @@ -372,10 +373,13 @@ enum infoHdrAdjust {
// Second set of opcodes, when first code is 0x4F
enum infoHdrAdjust2 {
SET_RETURNKIND = 0, // 0x00-SET_RET_KIND_MAX Set ReturnKind to value
SET_NOGCREGIONS_CNT = SET_RETURNKIND + SET_RET_KIND_MAX + 1, // 0x04
FFFF_NOGCREGION_CNT = SET_NOGCREGIONS_CNT + SET_NOGCREGIONS_MAX + 1 // 0x09 There is a count (>SET_NOGCREGIONS_MAX) after the header encoding
};

#define HAS_UNTRACKED ((unsigned int) -1)
#define HAS_VARPTR ((unsigned int) -1)
#define HAS_NOGCREGIONS ((unsigned int) -1)

// 0 is a valid offset for the Reverse P/Invoke block
// So use -1 as the sentinel for invalid and -2 as the sentinel for present.
Expand Down Expand Up @@ -424,7 +428,7 @@ struct InfoHdrSmall {
unsigned short argCount; // 5,6 in bytes
unsigned int frameSize; // 7,8,9,10 in bytes
unsigned int untrackedCnt; // 11,12,13,14
unsigned int varPtrTableSize; // 15.16,17,18
unsigned int varPtrTableSize; // 15,16,17,18

// Checks whether "this" is compatible with "target".
// It is not an exact bit match as "this" could have some
Expand All @@ -442,7 +446,8 @@ struct InfoHdr : public InfoHdrSmall {
unsigned int syncStartOffset; // 23,24,25,26
unsigned int syncEndOffset; // 27,28,29,30
unsigned int revPInvokeOffset; // 31,32,33,34 Available GcInfo v2 onwards, previously undefined
// 35 bytes total
unsigned int noGCRegionCnt; // 35,36,37,38
// 39 bytes total

// Checks whether "this" is compatible with "target".
// It is not an exact bit match as "this" could have some
Expand All @@ -457,7 +462,8 @@ struct InfoHdr : public InfoHdrSmall {
target.varPtrTableSize != HAS_VARPTR &&
target.gsCookieOffset != HAS_GS_COOKIE_OFFSET &&
target.syncStartOffset != HAS_SYNC_OFFSET &&
target.revPInvokeOffset != HAS_REV_PINVOKE_FRAME_OFFSET);
target.revPInvokeOffset != HAS_REV_PINVOKE_FRAME_OFFSET &&
target.noGCRegionCnt != HAS_NOGCREGIONS);
#endif

// compare two InfoHdr's up to but not including the untrackCnt field
Expand Down Expand Up @@ -488,6 +494,13 @@ struct InfoHdr : public InfoHdrSmall {
(target.revPInvokeOffset == INVALID_REV_PINVOKE_OFFSET))
return false;

if (noGCRegionCnt != target.noGCRegionCnt) {
if (target.noGCRegionCnt <= SET_NOGCREGIONS_MAX)
return false;
else if (noGCRegionCnt != HAS_UNTRACKED)
return false;
}

return true;
}
};
Expand Down Expand Up @@ -518,6 +531,7 @@ inline void GetInfoHdr(int index, InfoHdr * header)
header->syncStartOffset = INVALID_SYNC_OFFSET;
header->syncEndOffset = INVALID_SYNC_OFFSET;
header->revPInvokeOffset = INVALID_REV_PINVOKE_OFFSET;
header->noGCRegionCnt = 0;
}

PTR_CBYTE FASTCALL decodeHeader(PTR_CBYTE table, UINT32 version, InfoHdr* header);
Expand Down
18 changes: 0 additions & 18 deletions src/coreclr/jit/codegenxarch.cpp
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Expand Up @@ -202,14 +202,10 @@ BasicBlock* CodeGen::genCallFinally(BasicBlock* block)
}
else
{
// TODO-Linux-x86: Do we need to handle the GC information for this NOP or JMP specially, as is done for other
// architectures?
#ifndef JIT32_GCENCODER
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^ This is the primary issue addressed by this PR

// Because of the way the flowgraph is connected, the liveness info for this one instruction
// after the call is not (can not be) correct in cases where a variable has a last use in the
// handler. So turn off GC reporting once we execute the call and reenable after the jmp/nop
GetEmitter()->emitDisableGC();
#endif // JIT32_GCENCODER

GetEmitter()->emitIns_J(INS_call, block->GetTarget());

Expand All @@ -229,9 +225,7 @@ BasicBlock* CodeGen::genCallFinally(BasicBlock* block)
inst_JMP(EJ_jmp, finallyContinuation);
}

#ifndef JIT32_GCENCODER
GetEmitter()->emitEnableGC();
#endif // JIT32_GCENCODER
}
}
#if defined(FEATURE_EH_WINDOWS_X86)
Expand Down Expand Up @@ -1879,11 +1873,9 @@ void CodeGen::genCodeForTreeNode(GenTree* treeNode)

switch (treeNode->gtOper)
{
#ifndef JIT32_GCENCODER
case GT_START_NONGC:
GetEmitter()->emitDisableGC();
break;
#endif // !defined(JIT32_GCENCODER)

case GT_START_PREEMPTGC:
// Kill callee saves GC registers, and create a label
Expand Down Expand Up @@ -3160,9 +3152,7 @@ void CodeGen::genCodeForStoreBlk(GenTreeBlk* storeBlkNode)
{
case GenTreeBlk::BlkOpKindCpObjRepInstr:
case GenTreeBlk::BlkOpKindCpObjUnroll:
#ifndef JIT32_GCENCODER
assert(!storeBlkNode->gtBlkOpGcUnsafe);
#endif
genCodeForCpObj(storeBlkNode->AsBlk());
break;

Expand All @@ -3172,9 +3162,7 @@ void CodeGen::genCodeForStoreBlk(GenTreeBlk* storeBlkNode)
break;

case GenTreeBlk::BlkOpKindRepInstr:
#ifndef JIT32_GCENCODER
assert(!storeBlkNode->gtBlkOpGcUnsafe);
#endif
if (isCopyBlk)
{
genCodeForCpBlkRepMovs(storeBlkNode);
Expand All @@ -3188,12 +3176,10 @@ void CodeGen::genCodeForStoreBlk(GenTreeBlk* storeBlkNode)
case GenTreeBlk::BlkOpKindUnroll:
if (isCopyBlk)
{
#ifndef JIT32_GCENCODER
if (storeBlkNode->gtBlkOpGcUnsafe)
{
GetEmitter()->emitDisableGC();
}
#endif
if (storeBlkNode->gtBlkOpKind == GenTreeBlk::BlkOpKindUnroll)
{
genCodeForCpBlkUnroll(storeBlkNode);
Expand All @@ -3203,18 +3189,14 @@ void CodeGen::genCodeForStoreBlk(GenTreeBlk* storeBlkNode)
assert(storeBlkNode->gtBlkOpKind == GenTreeBlk::BlkOpKindUnrollMemmove);
genCodeForMemmove(storeBlkNode);
}
#ifndef JIT32_GCENCODER
if (storeBlkNode->gtBlkOpGcUnsafe)
{
GetEmitter()->emitEnableGC();
}
#endif
}
else
{
#ifndef JIT32_GCENCODER
assert(!storeBlkNode->gtBlkOpGcUnsafe);
#endif
genCodeForInitBlkUnroll(storeBlkNode);
}
break;
Expand Down
2 changes: 0 additions & 2 deletions src/coreclr/jit/emit.cpp
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Expand Up @@ -10597,7 +10597,6 @@ regMaskTP emitter::emitGetGCRegsKilledByNoGCCall(CorInfoHelpFunc helper)
return result;
}

#if !defined(JIT32_GCENCODER)
//------------------------------------------------------------------------
// emitDisableGC: Requests that the following instruction groups are not GC-interruptible.
//
Expand Down Expand Up @@ -10689,4 +10688,3 @@ void emitter::emitEnableGC()
JITDUMP("Enable GC: still %u no-gc requests\n", emitNoGCRequestCount);
}
}
#endif // !defined(JIT32_GCENCODER)
2 changes: 0 additions & 2 deletions src/coreclr/jit/emit.h
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Expand Up @@ -2891,11 +2891,9 @@ class emitter

void emitNewIG();

#if !defined(JIT32_GCENCODER)
void emitDisableGC();
void emitEnableGC();
bool emitGCDisabled();
#endif // !defined(JIT32_GCENCODER)

#if defined(TARGET_XARCH)
static bool emitAlignInstHasNoCode(instrDesc* id);
Expand Down
9 changes: 8 additions & 1 deletion src/coreclr/jit/emitinl.h
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Expand Up @@ -585,10 +585,17 @@ inline bool insIsCMOV(instruction ins)
* false. Returns the final result of the callback.
*/
template <typename Callback>
bool emitter::emitGenNoGCLst(Callback& cb)
bool emitter::emitGenNoGCLst(Callback& cb, bool skipAllPrologsAndEpilogs /* = false */)
{
for (insGroup* ig = emitIGlist; ig; ig = ig->igNext)
{
if (skipAllPrologsAndEpilogs)
{
if (ig == emitPrologIG)
continue;
if (ig->igFlags & (IGF_EPILOG | IGF_FUNCLET_PROLOG | IGF_FUNCLET_EPILOG))
continue;
}
if ((ig->igFlags & IGF_NOGCINTERRUPT) && ig->igSize > 0)
{
emitter::instrDesc* id = emitFirstInstrDesc(ig->igData);
Expand Down
2 changes: 1 addition & 1 deletion src/coreclr/jit/emitpub.h
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Expand Up @@ -43,7 +43,7 @@ unsigned emitEndCodeGen(Compiler* comp,
unsigned emitGetEpilogCnt();

template <typename Callback>
bool emitGenNoGCLst(Callback& cb);
bool emitGenNoGCLst(Callback& cb, bool skipAllPrologsAndEpilogs = false);

void emitBegProlog();
unsigned emitGetPrologOffsetEstimate();
Expand Down
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