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Move the NoGC helper classification to HelperCallProperties (#105040)
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Fixes a TODO and centralizes the assumptions about helpers in one place.
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@SingleAccretion
SingleAccretion authored Jul 18, 2024
1 parent 49a2a55 commit 0785303
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Showing 6 changed files with 58 additions and 94 deletions.
2 changes: 1 addition & 1 deletion src/coreclr/jit/compiler.hpp
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Original file line number Diff line number Diff line change
Expand Up @@ -3322,7 +3322,7 @@ inline bool Compiler::IsPotentialGCSafePoint(GenTree* tree) const
if (((tree->gtFlags & GTF_CALL) != 0))
{
// if this is not a No-GC helper
if (!tree->IsCall() || !emitter::emitNoGChelper(tree->AsCall()->GetHelperNum()))
if (!tree->IsHelperCall() || !s_helperCallProperties.IsNoGC(tree->AsCall()->GetHelperNum()))
{
// assume that we have a safe point.
return true;
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81 changes: 3 additions & 78 deletions src/coreclr/jit/emit.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -2780,82 +2780,6 @@ emitter::instrDesc* emitter::emitNewInstrCnsDsp(emitAttr size, target_ssize_t cn
}
}

//------------------------------------------------------------------------
// emitNoGChelper: Returns true if garbage collection won't happen within the helper call.
//
// Notes:
// There is no need to record live pointers for such call sites.
//
// Arguments:
// helpFunc - a helper signature for the call, can be CORINFO_HELP_UNDEF, that means that the call is not a helper.
//
// Return value:
// true if GC can't happen within this call, false otherwise.
bool emitter::emitNoGChelper(CorInfoHelpFunc helpFunc)
{
// TODO-Throughput: Make this faster (maybe via a simple table of bools?)

switch (helpFunc)
{
case CORINFO_HELP_UNDEF:
return false;

case CORINFO_HELP_PROF_FCN_LEAVE:
case CORINFO_HELP_PROF_FCN_ENTER:
case CORINFO_HELP_PROF_FCN_TAILCALL:
case CORINFO_HELP_LLSH:
case CORINFO_HELP_LRSH:
case CORINFO_HELP_LRSZ:

// case CORINFO_HELP_LMUL:
// case CORINFO_HELP_LDIV:
// case CORINFO_HELP_LMOD:
// case CORINFO_HELP_ULDIV:
// case CORINFO_HELP_ULMOD:

#ifdef TARGET_X86
case CORINFO_HELP_ASSIGN_REF_EAX:
case CORINFO_HELP_ASSIGN_REF_ECX:
case CORINFO_HELP_ASSIGN_REF_EBX:
case CORINFO_HELP_ASSIGN_REF_EBP:
case CORINFO_HELP_ASSIGN_REF_ESI:
case CORINFO_HELP_ASSIGN_REF_EDI:

case CORINFO_HELP_CHECKED_ASSIGN_REF_EAX:
case CORINFO_HELP_CHECKED_ASSIGN_REF_ECX:
case CORINFO_HELP_CHECKED_ASSIGN_REF_EBX:
case CORINFO_HELP_CHECKED_ASSIGN_REF_EBP:
case CORINFO_HELP_CHECKED_ASSIGN_REF_ESI:
case CORINFO_HELP_CHECKED_ASSIGN_REF_EDI:
#endif

case CORINFO_HELP_ASSIGN_REF:
case CORINFO_HELP_CHECKED_ASSIGN_REF:
case CORINFO_HELP_ASSIGN_BYREF:

case CORINFO_HELP_GET_GCSTATIC_BASE_NOCTOR:
case CORINFO_HELP_GET_NONGCSTATIC_BASE_NOCTOR:

case CORINFO_HELP_INIT_PINVOKE_FRAME:

case CORINFO_HELP_FAIL_FAST:
case CORINFO_HELP_STACK_PROBE:

case CORINFO_HELP_CHECK_OBJ:

// never present on stack at the time of GC
case CORINFO_HELP_TAILCALL:
case CORINFO_HELP_JIT_REVERSE_PINVOKE_ENTER:
case CORINFO_HELP_JIT_REVERSE_PINVOKE_ENTER_TRACK_TRANSITIONS:

case CORINFO_HELP_VALIDATE_INDIRECT_CALL:
return true;

default:
return false;
}
}

//------------------------------------------------------------------------
// emitNoGChelper: Returns true if garbage collection won't happen within the helper call.
//
Expand All @@ -2867,14 +2791,15 @@ bool emitter::emitNoGChelper(CorInfoHelpFunc helpFunc)
//
// Return value:
// true if GC can't happen within this call, false otherwise.
//
bool emitter::emitNoGChelper(CORINFO_METHOD_HANDLE methHnd)
{
CorInfoHelpFunc helpFunc = Compiler::eeGetHelperNum(methHnd);
if (helpFunc == CORINFO_HELP_UNDEF)
{
return false;
}
return emitNoGChelper(helpFunc);
return Compiler::s_helperCallProperties.IsNoGC(helpFunc);
}

/*****************************************************************************
Expand Down Expand Up @@ -10430,7 +10355,7 @@ regMaskTP emitter::emitGetGCRegsSavedOrModified(CORINFO_METHOD_HANDLE methHnd)
//
regMaskTP emitter::emitGetGCRegsKilledByNoGCCall(CorInfoHelpFunc helper)
{
assert(emitNoGChelper(helper));
assert(emitNoGChelper(Compiler::eeFindHelper(helper)));
regMaskTP result;
switch (helper)
{
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3 changes: 2 additions & 1 deletion src/coreclr/jit/emit.h
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Original file line number Diff line number Diff line change
Expand Up @@ -3159,13 +3159,14 @@ class emitter
/* The following is used to distinguish helper vs non-helper calls */
/************************************************************************/

static bool emitNoGChelper(CorInfoHelpFunc helpFunc);
private:
static bool emitNoGChelper(CORINFO_METHOD_HANDLE methHnd);

/************************************************************************/
/* The following logic keeps track of live GC ref values */
/************************************************************************/

public:
bool emitFullArgInfo; // full arg info (including non-ptr arg)?
bool emitFullGCinfo; // full GC pointer maps?
bool emitFullyInt; // fully interruptible code?
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2 changes: 1 addition & 1 deletion src/coreclr/jit/optimizer.cpp
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Expand Up @@ -6104,7 +6104,7 @@ void Compiler::optRemoveRedundantZeroInits()
{
// If compMethodRequiresPInvokeFrame() returns true, lower may later
// insert a call to CORINFO_HELP_INIT_PINVOKE_FRAME but that is not a gc-safe point.
assert(emitter::emitNoGChelper(CORINFO_HELP_INIT_PINVOKE_FRAME));
assert(s_helperCallProperties.IsNoGC(CORINFO_HELP_INIT_PINVOKE_FRAME));

if (!lclDsc->HasGCPtr() || (!GetInterruptible() && !hasGCSafePoint))
{
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56 changes: 43 additions & 13 deletions src/coreclr/jit/utils.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -1520,13 +1520,16 @@ void HelperCallProperties::init()
bool mutatesHeap = false; // true if any previous heap objects [are|can be] modified
bool mayRunCctor = false; // true if the helper call may cause a static constructor to be run.
bool isNoEscape = false; // true if none of the GC ref arguments can escape
bool isNoGC = false; // true is the helper cannot trigger GC

switch (helper)
{
// Arithmetic helpers that cannot throw
case CORINFO_HELP_LLSH:
case CORINFO_HELP_LRSH:
case CORINFO_HELP_LRSZ:
isNoGC = true;
FALLTHROUGH;
case CORINFO_HELP_LMUL:
case CORINFO_HELP_LNG2DBL:
case CORINFO_HELP_ULNG2DBL:
Expand All @@ -1538,7 +1541,6 @@ void HelperCallProperties::init()
case CORINFO_HELP_DBLREM:
case CORINFO_HELP_FLTROUND:
case CORINFO_HELP_DBLROUND:

isPure = true;
noThrow = true;
break;
Expand Down Expand Up @@ -1729,6 +1731,8 @@ void HelperCallProperties::init()

case CORINFO_HELP_GET_GCSTATIC_BASE_NOCTOR:
case CORINFO_HELP_GET_NONGCSTATIC_BASE_NOCTOR:
isNoGC = true;
FALLTHROUGH;
case CORINFO_HELP_GETDYNAMIC_GCSTATIC_BASE_NOCTOR:
case CORINFO_HELP_GETDYNAMIC_NONGCSTATIC_BASE_NOCTOR:
case CORINFO_HELP_GETPINNED_GCSTATIC_BASE_NOCTOR:
Expand All @@ -1749,24 +1753,41 @@ void HelperCallProperties::init()
nonNullReturn = true;
break;

#ifdef TARGET_X86
case CORINFO_HELP_ASSIGN_REF_EAX:
case CORINFO_HELP_ASSIGN_REF_ECX:
case CORINFO_HELP_ASSIGN_REF_EBX:
case CORINFO_HELP_ASSIGN_REF_EBP:
case CORINFO_HELP_ASSIGN_REF_ESI:
case CORINFO_HELP_ASSIGN_REF_EDI:
case CORINFO_HELP_CHECKED_ASSIGN_REF_EAX:
case CORINFO_HELP_CHECKED_ASSIGN_REF_ECX:
case CORINFO_HELP_CHECKED_ASSIGN_REF_EBX:
case CORINFO_HELP_CHECKED_ASSIGN_REF_EBP:
case CORINFO_HELP_CHECKED_ASSIGN_REF_ESI:
case CORINFO_HELP_CHECKED_ASSIGN_REF_EDI:
#endif
// GC Write barrier support
// TODO-ARM64-Bug?: Can these throw or not?
case CORINFO_HELP_ASSIGN_REF:
case CORINFO_HELP_CHECKED_ASSIGN_REF:
case CORINFO_HELP_ASSIGN_REF_ENSURE_NONHEAP:
case CORINFO_HELP_ASSIGN_BYREF:
isNoGC = true;
FALLTHROUGH;
case CORINFO_HELP_ASSIGN_REF_ENSURE_NONHEAP:
case CORINFO_HELP_BULK_WRITEBARRIER:

mutatesHeap = true;
break;

// Accessing fields (write)
case CORINFO_HELP_ARRADDR_ST:

mutatesHeap = true;
break;

// These helper calls always throw an exception
case CORINFO_HELP_FAIL_FAST:
isNoGC = true;
FALLTHROUGH;
case CORINFO_HELP_OVERFLOW:
case CORINFO_HELP_VERIFICATION:
case CORINFO_HELP_RNGCHKFAIL:
Expand All @@ -1779,17 +1800,14 @@ void HelperCallProperties::init()
case CORINFO_HELP_THROW_NOT_IMPLEMENTED:
case CORINFO_HELP_THROW_PLATFORM_NOT_SUPPORTED:
case CORINFO_HELP_THROW_TYPE_NOT_SUPPORTED:
case CORINFO_HELP_FAIL_FAST:
case CORINFO_HELP_METHOD_ACCESS_EXCEPTION:
case CORINFO_HELP_FIELD_ACCESS_EXCEPTION:
case CORINFO_HELP_CLASS_ACCESS_EXCEPTION:

alwaysThrow = true;
break;

// These helper calls may throw an exception
case CORINFO_HELP_MON_EXIT_STATIC:

break;

// This is a debugging aid; it simply returns a constant address.
Expand All @@ -1798,26 +1816,37 @@ void HelperCallProperties::init()
noThrow = true;
break;

case CORINFO_HELP_INIT_PINVOKE_FRAME:
case CORINFO_HELP_JIT_REVERSE_PINVOKE_ENTER: // Never present on stack at the time of GC.
case CORINFO_HELP_JIT_REVERSE_PINVOKE_ENTER_TRACK_TRANSITIONS:
isNoGC = true;
FALLTHROUGH;
case CORINFO_HELP_DBG_IS_JUST_MY_CODE:
case CORINFO_HELP_BBT_FCN_ENTER:
case CORINFO_HELP_POLL_GC:
case CORINFO_HELP_MON_ENTER:
case CORINFO_HELP_MON_EXIT:
case CORINFO_HELP_MON_ENTER_STATIC:
case CORINFO_HELP_JIT_REVERSE_PINVOKE_ENTER:
case CORINFO_HELP_JIT_REVERSE_PINVOKE_EXIT:
case CORINFO_HELP_GETFIELDADDR:
case CORINFO_HELP_INIT_PINVOKE_FRAME:
case CORINFO_HELP_JIT_PINVOKE_BEGIN:
case CORINFO_HELP_JIT_PINVOKE_END:

noThrow = true;
break;

// Not sure how to handle optimization involving the rest of these helpers
default:
case CORINFO_HELP_TAILCALL: // Never present on stack at the time of GC.
case CORINFO_HELP_STACK_PROBE:
case CORINFO_HELP_CHECK_OBJ:
case CORINFO_HELP_VALIDATE_INDIRECT_CALL:
case CORINFO_HELP_PROF_FCN_LEAVE:
case CORINFO_HELP_PROF_FCN_ENTER:
case CORINFO_HELP_PROF_FCN_TAILCALL:
isNoGC = true;
mutatesHeap = true; // Conservatively.
break;

// The most pessimistic results are returned for these helpers
default:
// The most pessimistic results are returned for these helpers.
mutatesHeap = true;
break;
}
Expand All @@ -1830,6 +1859,7 @@ void HelperCallProperties::init()
m_mutatesHeap[helper] = mutatesHeap;
m_mayRunCctor[helper] = mayRunCctor;
m_isNoEscape[helper] = isNoEscape;
m_isNoGC[helper] = isNoGC;
}
}

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8 changes: 8 additions & 0 deletions src/coreclr/jit/utils.h
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Original file line number Diff line number Diff line change
Expand Up @@ -591,6 +591,7 @@ class HelperCallProperties
bool m_mutatesHeap[CORINFO_HELP_COUNT];
bool m_mayRunCctor[CORINFO_HELP_COUNT];
bool m_isNoEscape[CORINFO_HELP_COUNT];
bool m_isNoGC[CORINFO_HELP_COUNT];

void init();

Expand Down Expand Up @@ -655,6 +656,13 @@ class HelperCallProperties
assert(helperId < CORINFO_HELP_COUNT);
return m_isNoEscape[helperId];
}

bool IsNoGC(CorInfoHelpFunc helperId)
{
assert(helperId > CORINFO_HELP_UNDEF);
assert(helperId < CORINFO_HELP_COUNT);
return m_isNoGC[helperId];
}
};

//*****************************************************************************
Expand Down

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