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fgbasic.cpp
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// Licensed to the .NET Foundation under one or more agreements.
// The .NET Foundation licenses this file to you under the MIT license.
#include "jitpch.h"
#ifdef _MSC_VER
#pragma hdrstop
#endif
// Flowgraph Construction and Maintenance
//------------------------------------------------------------------------------
// fgCanonicalizeFirstBB: Canonicalize the method entry to be dominate all
// blocks in the BB and to be executed exactly once.
//
// Returns:
// Suitable phase status.
//
PhaseStatus Compiler::fgCanonicalizeFirstBB()
{
if (fgFirstBB->hasTryIndex())
{
JITDUMP("Canonicalizing entry because it currently is the beginning of a try region\n");
}
else if (fgFirstBB->bbPreds != nullptr)
{
JITDUMP("Canonicalizing entry because it currently has predecessors\n");
}
else if (opts.compDbgCode && !fgFirstBB->HasFlag(BBF_INTERNAL))
{
// For debug ensure the first BB is internal so as to not conflate user
// code with JIT added code.
JITDUMP("Canonicalizing entry because it currently is a user BB and we are generating debug code\n");
}
else
{
return PhaseStatus::MODIFIED_NOTHING;
}
fgCreateNewInitBB();
return PhaseStatus::MODIFIED_EVERYTHING;
}
//------------------------------------------------------------------------------
// fgCreateNewInitBB:
// Create a new init BB at the beginning of the function.
//
void Compiler::fgCreateNewInitBB()
{
// The first block has an implicit ref count which we must remove. Note the
// ref count could be greater than one, if the first block is targeted by a
// branch.
assert(fgFirstBB->bbRefs >= 1);
fgFirstBB->bbRefs--;
BasicBlock* block = BasicBlock::New(this);
// If we have profile data determine the weight of the initBB BB
//
if (fgFirstBB->hasProfileWeight())
{
// If current entry has preds, sum up those weights
//
weight_t nonEntryWeight = 0;
for (FlowEdge* const edge : fgFirstBB->PredEdges())
{
nonEntryWeight += edge->getLikelyWeight();
}
// entry weight is weight not from any pred
//
weight_t const entryWeight = fgFirstBB->bbWeight - nonEntryWeight;
if (entryWeight <= 0)
{
// If the result is clearly nonsensical, just inherit
//
JITDUMP("\fgCanonicalizeFirstBB: Profile data could not be locally repaired. Data %s inconsistent.\n",
fgPgoConsistent ? "is now" : "was already");
if (fgPgoConsistent)
{
Metrics.ProfileInconsistentScratchBB++;
fgPgoConsistent = false;
}
block->inheritWeight(fgFirstBB);
}
else
{
block->setBBProfileWeight(entryWeight);
}
}
// The new scratch bb will fall through to the old first bb
FlowEdge* const edge = fgAddRefPred(fgFirstBB, block);
block->SetKindAndTargetEdge(BBJ_ALWAYS, edge);
fgInsertBBbefore(fgFirstBB, block);
// Set the expected flags
block->SetFlags(BBF_INTERNAL);
// This new first BB has an implicit ref, and no others.
//
assert(fgPredsComputed);
block->bbRefs = 1;
JITDUMP("New init " FMT_BB "\n", block->bbNum);
}
/*
Removes a block from the return block list
*/
void Compiler::fgRemoveReturnBlock(BasicBlock* block)
{
if (fgReturnBlocks == nullptr)
{
return;
}
if (fgReturnBlocks->block == block)
{
// It's the 1st entry, assign new head of list.
fgReturnBlocks = fgReturnBlocks->next;
return;
}
for (BasicBlockList* retBlocks = fgReturnBlocks; retBlocks->next != nullptr; retBlocks = retBlocks->next)
{
if (retBlocks->next->block == block)
{
// Found it; splice it out.
retBlocks->next = retBlocks->next->next;
return;
}
}
}
//------------------------------------------------------------------------
// fgConvertBBToThrowBB: Change a given block to a throw block.
//
// Arguments:
// block - block in question
//
void Compiler::fgConvertBBToThrowBB(BasicBlock* block)
{
JITDUMP("Converting " FMT_BB " to BBJ_THROW\n", block->bbNum);
assert(fgPredsComputed);
// Ordering of the following operations matters.
// First, if we are looking at the first block of a callfinally pair, remove the pairing.
// Don't actually remove the BBJ_CALLFINALLYRET as that might affect block iteration in
// the callers.
if (block->isBBCallFinallyPair())
{
BasicBlock* const leaveBlock = block->Next();
fgPrepareCallFinallyRetForRemoval(leaveBlock);
}
// Scrub this block from the pred lists of any successors
bool profileInconsistent = false;
for (BasicBlock* const succBlock : block->Succs(this))
{
FlowEdge* const succEdge = fgRemoveAllRefPreds(succBlock, block);
if (block->hasProfileWeight() && succBlock->hasProfileWeight())
{
succBlock->decreaseBBProfileWeight(succEdge->getLikelyWeight());
profileInconsistent |= (succBlock->NumSucc() > 0);
}
}
if (profileInconsistent)
{
JITDUMP("Flow removal of " FMT_BB " needs to be propagated. Data %s inconsistent.\n", block->bbNum,
fgPgoConsistent ? "is now" : "was already");
fgPgoConsistent = false;
}
// Update jump kind after the scrub.
block->SetKindAndTargetEdge(BBJ_THROW);
block->RemoveFlags(BBF_RETLESS_CALL); // no longer a BBJ_CALLFINALLY
}
/*****************************************************************************
* fgChangeSwitchBlock:
*
* We have a BBJ_SWITCH jump at 'oldSwitchBlock' and we want to move this
* switch jump over to 'newSwitchBlock'. All of the blocks that are jumped
* to from jumpTab[] need to have their predecessor lists updated by removing
* the 'oldSwitchBlock' and adding 'newSwitchBlock'.
*/
void Compiler::fgChangeSwitchBlock(BasicBlock* oldSwitchBlock, BasicBlock* newSwitchBlock)
{
noway_assert(oldSwitchBlock != nullptr);
noway_assert(newSwitchBlock != nullptr);
noway_assert(oldSwitchBlock->KindIs(BBJ_SWITCH));
assert(fgPredsComputed);
// Walk the switch's jump table, updating the predecessor for each branch.
BBswtDesc* swtDesc = oldSwitchBlock->GetSwitchTargets();
for (unsigned i = 0; i < swtDesc->bbsCount; i++)
{
FlowEdge* succEdge = swtDesc->bbsDstTab[i];
assert(succEdge != nullptr);
if (succEdge->getSourceBlock() != oldSwitchBlock)
{
// swtDesc can have duplicate targets, so we may have updated this edge already
//
assert(succEdge->getSourceBlock() == newSwitchBlock);
assert(succEdge->getDupCount() > 1);
}
else
{
// Redirect edge's source block from oldSwitchBlock to newSwitchBlock,
// and keep successor block's pred list in order
//
fgReplacePred(succEdge, newSwitchBlock);
}
}
if (m_switchDescMap != nullptr)
{
SwitchUniqueSuccSet uniqueSuccSet;
// If already computed and cached the unique descriptors for the old block, let's
// update those for the new block.
if (m_switchDescMap->Lookup(oldSwitchBlock, &uniqueSuccSet))
{
m_switchDescMap->Set(newSwitchBlock, uniqueSuccSet, BlockToSwitchDescMap::Overwrite);
}
else
{
fgInvalidateSwitchDescMapEntry(newSwitchBlock);
}
fgInvalidateSwitchDescMapEntry(oldSwitchBlock);
}
}
//------------------------------------------------------------------------
// fgChangeEhfBlock: We have a BBJ_EHFINALLYRET block at 'oldBlock' and we want to move this
// to 'newBlock'. All of the 'oldBlock' successors need to have their predecessor lists updated
// by removing edges to 'oldBlock' and adding edges to 'newBlock'.
//
// Arguments:
// oldBlock - previous BBJ_EHFINALLYRET block
// newBlock - block that is replacing 'oldBlock'
//
void Compiler::fgChangeEhfBlock(BasicBlock* oldBlock, BasicBlock* newBlock)
{
assert(oldBlock != nullptr);
assert(newBlock != nullptr);
assert(oldBlock->KindIs(BBJ_EHFINALLYRET));
assert(fgPredsComputed);
BBehfDesc* ehfDesc = oldBlock->GetEhfTargets();
for (unsigned i = 0; i < ehfDesc->bbeCount; i++)
{
FlowEdge* succEdge = ehfDesc->bbeSuccs[i];
fgReplacePred(succEdge, newBlock);
}
}
//------------------------------------------------------------------------
// fgReplaceEhfSuccessor: update BBJ_EHFINALLYRET block so that all control
// that previously flowed to oldSucc now flows to newSucc. It is assumed
// that oldSucc is currently a successor of `block`. We only allow a successor
// block to appear once in the successor list. Thus, if the new successor
// already exists in the list, we simply remove the old successor.
//
// Arguments:
// block - BBJ_EHFINALLYRET block
// newSucc - new successor
// oldSucc - old successor
//
void Compiler::fgReplaceEhfSuccessor(BasicBlock* block, BasicBlock* oldSucc, BasicBlock* newSucc)
{
assert(block != nullptr);
assert(oldSucc != nullptr);
assert(newSucc != nullptr);
assert(block->KindIs(BBJ_EHFINALLYRET));
assert(fgPredsComputed);
BBehfDesc* const ehfDesc = block->GetEhfTargets();
const unsigned succCount = ehfDesc->bbeCount;
FlowEdge** const succTab = ehfDesc->bbeSuccs;
// Walk the successor table looking for the old successor, which we expect to find only once.
unsigned oldSuccNum = UINT_MAX;
unsigned newSuccNum = UINT_MAX;
for (unsigned i = 0; i < succCount; i++)
{
assert(succTab[i]->getSourceBlock() == block);
if (succTab[i]->getDestinationBlock() == newSucc)
{
assert(newSuccNum == UINT_MAX);
newSuccNum = i;
}
if (succTab[i]->getDestinationBlock() == oldSucc)
{
assert(oldSuccNum == UINT_MAX);
oldSuccNum = i;
}
}
noway_assert((oldSuccNum != UINT_MAX) && "Did not find oldSucc in succTab[]");
if (newSuccNum != UINT_MAX)
{
// The new successor is already in the table; simply remove the old one.
fgRemoveEhfSuccessor(block, oldSuccNum);
JITDUMP("Remove existing BBJ_EHFINALLYRET " FMT_BB " successor " FMT_BB "; replacement successor " FMT_BB
" already exists in list\n",
block->bbNum, oldSucc->bbNum, newSucc->bbNum);
}
else
{
// Remove the old edge [block => oldSucc]
//
fgRemoveAllRefPreds(oldSucc, block);
// Create the new edge [block => newSucc]
//
FlowEdge* const newEdge = fgAddRefPred(newSucc, block);
// Replace the old one with the new one.
//
succTab[oldSuccNum] = newEdge;
JITDUMP("Replace BBJ_EHFINALLYRET " FMT_BB " successor " FMT_BB " with " FMT_BB "\n", block->bbNum,
oldSucc->bbNum, newSucc->bbNum);
}
}
//------------------------------------------------------------------------
// fgRemoveEhfSuccessor: update BBJ_EHFINALLYRET block to remove the successor at `succIndex`
// in the block's jump table.
// Updates the predecessor list of the successor, if necessary.
//
// Arguments:
// block - BBJ_EHFINALLYRET block
// succIndex - index of the successor in block->GetEhfTargets()->bbeSuccs
//
void Compiler::fgRemoveEhfSuccessor(BasicBlock* block, const unsigned succIndex)
{
assert(block != nullptr);
assert(block->KindIs(BBJ_EHFINALLYRET));
assert(fgPredsComputed);
BBehfDesc* const ehfDesc = block->GetEhfTargets();
const unsigned succCount = ehfDesc->bbeCount;
FlowEdge** succTab = ehfDesc->bbeSuccs;
assert(succIndex < succCount);
FlowEdge* succEdge = succTab[succIndex];
fgRemoveRefPred(succEdge);
// If succEdge not the last entry, move everything after in the table down one slot.
if ((succIndex + 1) < succCount)
{
memmove_s(&succTab[succIndex], (succCount - succIndex) * sizeof(FlowEdge*), &succTab[succIndex + 1],
(succCount - succIndex - 1) * sizeof(FlowEdge*));
}
#ifdef DEBUG
// We only expect to see a successor once in the table.
for (unsigned i = succIndex; i < (succCount - 1); i++)
{
assert(succTab[i]->getDestinationBlock() != succEdge->getDestinationBlock());
}
#endif // DEBUG
ehfDesc->bbeCount--;
}
//------------------------------------------------------------------------
// fgRemoveEhfSuccessor: Removes `succEdge` from its BBJ_EHFINALLYRET source block's jump table.
// Updates the predecessor list of the successor block, if necessary.
//
// Arguments:
// block - BBJ_EHFINALLYRET block
// succEdge - FlowEdge* to be removed from predecessor block's jump table
//
void Compiler::fgRemoveEhfSuccessor(FlowEdge* succEdge)
{
assert(succEdge != nullptr);
assert(fgPredsComputed);
BasicBlock* block = succEdge->getSourceBlock();
assert(block != nullptr);
assert(block->KindIs(BBJ_EHFINALLYRET));
fgRemoveRefPred(succEdge);
BBehfDesc* const ehfDesc = block->GetEhfTargets();
const unsigned succCount = ehfDesc->bbeCount;
FlowEdge** succTab = ehfDesc->bbeSuccs;
bool found = false;
// Search succTab for succEdge so we can splice it out of the table.
for (unsigned i = 0; i < succCount; i++)
{
if (succTab[i] == succEdge)
{
// If succEdge not the last entry, move everything after in the table down one slot.
if ((i + 1) < succCount)
{
memmove_s(&succTab[i], (succCount - i) * sizeof(FlowEdge*), &succTab[i + 1],
(succCount - i - 1) * sizeof(FlowEdge*));
}
found = true;
#ifdef DEBUG
// We only expect to see a successor once in the table.
for (; i < (succCount - 1); i++)
{
assert(succTab[i]->getDestinationBlock() != succEdge->getDestinationBlock());
}
#endif // DEBUG
}
}
assert(found);
ehfDesc->bbeCount--;
}
//------------------------------------------------------------------------
// Compiler::fgReplaceJumpTarget: For a given block, replace the target 'oldTarget' with 'newTarget'.
//
// Arguments:
// block - the block in which a jump target will be replaced.
// newTarget - the new branch target of the block.
// oldTarget - the old branch target of the block.
//
// Notes:
// 1. Only branches are changed: BBJ_ALWAYS, the non-fallthrough path of BBJ_COND, BBJ_SWITCH, etc.
// We assert for other jump kinds.
// 2. All branch targets found are updated. If there are multiple ways for a block
// to reach 'oldTarget' (e.g., multiple arms of a switch), all of them are changed.
// 3. The predecessor lists are updated.
// 4. If any switch table entry was updated, the switch table "unique successor" cache is invalidated.
//
void Compiler::fgReplaceJumpTarget(BasicBlock* block, BasicBlock* oldTarget, BasicBlock* newTarget)
{
assert(block != nullptr);
assert(fgPredsComputed);
switch (block->GetKind())
{
case BBJ_CALLFINALLY:
case BBJ_CALLFINALLYRET:
case BBJ_ALWAYS:
case BBJ_EHCATCHRET:
case BBJ_EHFILTERRET:
case BBJ_LEAVE: // This function can be called before import, so we still have BBJ_LEAVE
assert(block->TargetIs(oldTarget));
fgRedirectTargetEdge(block, newTarget);
break;
case BBJ_COND:
if (block->TrueTargetIs(oldTarget))
{
if (block->FalseEdgeIs(block->GetTrueEdge()))
{
// Branch was degenerate, simplify it first
//
fgRemoveConditionalJump(block);
assert(block->KindIs(BBJ_ALWAYS));
assert(block->TargetIs(oldTarget));
fgRedirectTargetEdge(block, newTarget);
}
else
{
fgRedirectTrueEdge(block, newTarget);
}
}
else
{
// Already degenerate cases should have taken the true path above
//
assert(block->FalseTargetIs(oldTarget));
assert(!block->TrueEdgeIs(block->GetFalseEdge()));
fgRedirectFalseEdge(block, newTarget);
}
if (block->KindIs(BBJ_COND) && block->TrueEdgeIs(block->GetFalseEdge()))
{
// Block became degenerate, simplify
//
fgRemoveConditionalJump(block);
assert(block->KindIs(BBJ_ALWAYS));
assert(block->TargetIs(newTarget));
}
break;
case BBJ_SWITCH:
{
unsigned const jumpCnt = block->GetSwitchTargets()->bbsCount;
FlowEdge** const jumpTab = block->GetSwitchTargets()->bbsDstTab;
bool existingEdge = false;
FlowEdge* oldEdge = nullptr;
FlowEdge* newEdge = nullptr;
bool changed = false;
for (unsigned i = 0; i < jumpCnt; i++)
{
if (jumpTab[i]->getDestinationBlock() == newTarget)
{
// The new target already has an edge from this switch statement.
// We'll need to add the likelihood from the edge we're redirecting
// to the existing edge. Note that if there is no existing edge,
// then we'll copy the likelihood from the existing edge we pass to
// `fgAddRefPred`. Note also that we can visit the same edge multiple
// times if there are multiple switch cases with the same target. The
// edge has a dup count and a single likelihood for all the possible
// paths to the target, so we only want to add the likelihood once
// despite visiting the duplicated edges in the `jumpTab` array
// multiple times.
existingEdge = true;
}
if (jumpTab[i]->getDestinationBlock() == oldTarget)
{
assert((oldEdge == nullptr) || (oldEdge == jumpTab[i]));
oldEdge = jumpTab[i];
fgRemoveRefPred(oldEdge);
newEdge = fgAddRefPred(newTarget, block, oldEdge);
jumpTab[i] = newEdge;
changed = true;
}
}
if (existingEdge)
{
assert(oldEdge != nullptr);
assert(oldEdge->getSourceBlock() == block);
assert(oldEdge->getDestinationBlock() == oldTarget);
assert(newEdge != nullptr);
assert(newEdge->getSourceBlock() == block);
assert(newEdge->getDestinationBlock() == newTarget);
newEdge->addLikelihood(oldEdge->getLikelihood());
}
assert(changed);
InvalidateUniqueSwitchSuccMap();
break;
}
case BBJ_EHFINALLYRET:
fgReplaceEhfSuccessor(block, oldTarget, newTarget);
break;
default:
assert(!"Block doesn't have a jump target!");
unreached();
break;
}
}
//------------------------------------------------------------------------
// fgReplacePred: redirects the given edge to a new predecessor block
//
// Arguments:
// edge - the edge whose source block we want to update
// newPred - the new predecessor block for edge
//
// Notes:
//
// This function assumes that all branches from the predecessor (practically, that all
// switch cases that target the successor block) are changed to branch from the new predecessor,
// with the same dup count.
//
// Note that the successor block's bbRefs is not changed, since it has the same number of
// references as before, just from a different predecessor block.
//
// Also note this may cause reordering of the pred list.
//
void Compiler::fgReplacePred(FlowEdge* edge, BasicBlock* const newPred)
{
assert(edge != nullptr);
assert(newPred != nullptr);
assert(edge->getSourceBlock() != newPred);
// Remove the edge, modify it, then add it back
//
BasicBlock* const target = edge->getDestinationBlock();
BasicBlock* const oldPred = edge->getSourceBlock();
FlowEdge** listp = fgGetPredInsertPoint(oldPred, target);
assert(*listp == edge);
*listp = edge->getNextPredEdge();
edge->setSourceBlock(newPred);
listp = fgGetPredInsertPoint(newPred, target);
edge->setNextPredEdge(*listp);
*listp = edge;
assert(target->checkPredListOrder());
}
/*****************************************************************************
* For a block that is in a handler region, find the first block of the most-nested
* handler containing the block.
*/
BasicBlock* Compiler::fgFirstBlockOfHandler(BasicBlock* block)
{
assert(block->hasHndIndex());
return ehGetDsc(block->getHndIndex())->ebdHndBeg;
}
#ifdef DEBUG
//------------------------------------------------------------------------
// fgInvalidateBBLookup: In non-Release builds, set fgBBs to a dummy value.
// After calling this, fgInitBBLookup must be called before using fgBBs again.
//
void Compiler::fgInvalidateBBLookup()
{
fgBBs = (BasicBlock**)0xCDCD;
}
#endif // DEBUG
/*****************************************************************************
*
* The following helps find a basic block given its PC offset.
*/
void Compiler::fgInitBBLookup()
{
BasicBlock** dscBBptr;
/* Allocate the basic block table */
dscBBptr = fgBBs = new (this, CMK_BasicBlock) BasicBlock*[fgBBcount];
/* Walk all the basic blocks, filling in the table */
for (BasicBlock* const block : Blocks())
{
*dscBBptr++ = block;
}
noway_assert(dscBBptr == fgBBs + fgBBcount);
}
BasicBlock* Compiler::fgLookupBB(unsigned addr)
{
unsigned lo;
unsigned hi;
/* Do a binary search */
for (lo = 0, hi = fgBBcount - 1;;)
{
AGAIN:;
if (lo > hi)
{
break;
}
unsigned mid = (lo + hi) / 2;
BasicBlock* dsc = fgBBs[mid];
// We introduce internal blocks for BBJ_CALLFINALLY. Skip over these.
while (dsc->HasFlag(BBF_INTERNAL))
{
dsc = dsc->Next();
mid++;
// We skipped over too many, Set hi back to the original mid - 1
if (mid > hi)
{
mid = (lo + hi) / 2;
hi = mid - 1;
goto AGAIN;
}
}
unsigned pos = dsc->bbCodeOffs;
if (pos < addr)
{
if ((lo == hi) && (lo == (fgBBcount - 1)))
{
noway_assert(addr == dsc->bbCodeOffsEnd);
return nullptr; // NULL means the end of method
}
lo = mid + 1;
continue;
}
if (pos > addr)
{
hi = mid - 1;
continue;
}
return dsc;
}
#ifdef DEBUG
printf("ERROR: Couldn't find basic block at offset %04X\n", addr);
#endif // DEBUG
NO_WAY("fgLookupBB failed.");
}
//------------------------------------------------------------------------
// FgStack: simple stack model for the inlinee's evaluation stack.
//
// Model the inputs available to various operations in the inline body.
// Tracks constants, arguments, array lengths.
class FgStack
{
public:
FgStack()
: slot0(SLOT_INVALID)
, slot1(SLOT_INVALID)
, depth(0)
{
// Empty
}
enum FgSlot
{
SLOT_INVALID = UINT_MAX,
SLOT_UNKNOWN = 0,
SLOT_CONSTANT = 1,
SLOT_ARRAYLEN = 2,
SLOT_ARGUMENT = 3
};
void Clear()
{
depth = 0;
}
void PushUnknown()
{
Push(SLOT_UNKNOWN);
}
void PushConstant()
{
Push(SLOT_CONSTANT);
}
void PushArrayLen()
{
Push(SLOT_ARRAYLEN);
}
void PushArgument(unsigned arg)
{
Push((FgSlot)(SLOT_ARGUMENT + arg));
}
FgSlot GetSlot0() const
{
return depth >= 1 ? slot0 : FgSlot::SLOT_UNKNOWN;
}
FgSlot GetSlot1() const
{
return depth >= 2 ? slot1 : FgSlot::SLOT_UNKNOWN;
}
FgSlot Top(const int n = 0)
{
if (n == 0)
{
return depth >= 1 ? slot0 : SLOT_UNKNOWN;
}
if (n == 1)
{
return depth == 2 ? slot1 : SLOT_UNKNOWN;
}
unreached();
}
static bool IsConstant(FgSlot value)
{
return value == SLOT_CONSTANT;
}
static bool IsConstantOrConstArg(FgSlot value, InlineInfo* info)
{
return IsConstant(value) || IsConstArgument(value, info);
}
static bool IsArrayLen(FgSlot value)
{
return value == SLOT_ARRAYLEN;
}
static bool IsArgument(FgSlot value)
{
return value >= SLOT_ARGUMENT;
}
static bool IsConstArgument(FgSlot value, InlineInfo* info)
{
if ((info == nullptr) || !IsArgument(value))
{
return false;
}
const unsigned argNum = value - SLOT_ARGUMENT;
if (argNum < info->argCnt)
{
return info->inlArgInfo[argNum].argIsInvariant;
}
return false;
}
static bool IsExactArgument(FgSlot value, InlineInfo* info)
{
if ((info == nullptr) || !IsArgument(value))
{
return false;
}
const unsigned argNum = value - SLOT_ARGUMENT;
if (argNum < info->argCnt)
{
return info->inlArgInfo[argNum].argIsExact;
}
return false;
}
static unsigned SlotTypeToArgNum(FgSlot value)
{
assert(IsArgument(value));
return value - SLOT_ARGUMENT;
}
bool IsStackTwoDeep() const
{
return depth == 2;
}
bool IsStackOneDeep() const
{
return depth == 1;
}
bool IsStackAtLeastOneDeep() const
{
return depth >= 1;
}
void Push(FgSlot slot)
{
assert(depth <= 2);
slot1 = slot0;
slot0 = slot;
if (depth < 2)
{
depth++;
}
}
private:
FgSlot slot0;
FgSlot slot1;
unsigned depth;
};
//------------------------------------------------------------------------
// fgFindJumpTargets: walk the IL stream, determining jump target offsets
//
// Type arguments:
// makeInlineObservations - whether or not to record inline observations about the method
//
// Arguments:
// codeAddr - base address of the IL code buffer
// codeSize - number of bytes in the IL code buffer
// jumpTarget - [OUT] bit vector for flagging jump targets
//
// Notes:
// If "makeInlineObservations" is true this method also makes
// various observations about the method that factor into inline
// decisions.
//
// May throw an exception if the IL is malformed.
//
// jumpTarget[N] is set to 1 if IL offset N is a jump target in the method.
//
// Also sets m_addrExposed and lvHasILStoreOp, ilHasMultipleILStoreOp in lvaTable[].
//
template <bool makeInlineObservations>
void Compiler::fgFindJumpTargets(const BYTE* codeAddr, IL_OFFSET codeSize, FixedBitVect* jumpTarget)
{
const BYTE* codeBegp = codeAddr;
const BYTE* codeEndp = codeAddr + codeSize;
unsigned varNum;
var_types varType = DUMMY_INIT(TYP_UNDEF); // TYP_ type
bool typeIsNormed = false;
FgStack pushedStack;
const bool isForceInline = (info.compFlags & CORINFO_FLG_FORCEINLINE) != 0;
const bool isInlining = compIsForInlining();
unsigned retBlocks = 0;
int prefixFlags = 0;
bool preciseScan = makeInlineObservations && compInlineResult->GetPolicy()->RequiresPreciseScan();
const bool resolveTokens = preciseScan;
// Track offsets where IL instructions begin in DEBUG builds. Used to
// validate debug info generated by the JIT.
assert(codeSize == compInlineContext->GetILSize());
INDEBUG(FixedBitVect* ilInstsSet = FixedBitVect::bitVectInit(codeSize, this));
if (makeInlineObservations)
{
// Set default values for profile (to avoid NoteFailed in CALLEE_IL_CODE_SIZE's handler)
// these will be overridden later.
compInlineResult->NoteBool(InlineObservation::CALLSITE_HAS_PROFILE_WEIGHTS, true);
compInlineResult->NoteDouble(InlineObservation::CALLSITE_PROFILE_FREQUENCY, 1.0);
// Observe force inline state and code size.
compInlineResult->NoteBool(InlineObservation::CALLEE_IS_FORCE_INLINE, isForceInline);
compInlineResult->NoteInt(InlineObservation::CALLEE_IL_CODE_SIZE, codeSize);
// Determine if call site is within a try.
if (isInlining && impInlineInfo->iciBlock->hasTryIndex())
{
compInlineResult->Note(InlineObservation::CALLSITE_IN_TRY_REGION);
}
// Determine if the call site is in a no-return block
if (isInlining && impInlineInfo->iciBlock->KindIs(BBJ_THROW))
{
compInlineResult->Note(InlineObservation::CALLSITE_IN_NORETURN_REGION);
}
// Determine if the call site is in a loop.
if (isInlining && impInlineInfo->iciBlock->HasFlag(BBF_BACKWARD_JUMP))
{
compInlineResult->Note(InlineObservation::CALLSITE_IN_LOOP);
}
#ifdef DEBUG
// If inlining, this method should still be a candidate.
if (isInlining)
{
assert(compInlineResult->IsCandidate());
}
#endif // DEBUG
// note that we're starting to look at the opcodes.
compInlineResult->Note(InlineObservation::CALLEE_BEGIN_OPCODE_SCAN);
}
CORINFO_RESOLVED_TOKEN resolvedToken;
OPCODE opcode = CEE_NOP;
OPCODE prevOpcode = CEE_NOP;
bool handled = false;
while (codeAddr < codeEndp)
{
prevOpcode = opcode;
opcode = (OPCODE)getU1LittleEndian(codeAddr);
INDEBUG(ilInstsSet->bitVectSet((UINT)(codeAddr - codeBegp)));
codeAddr += sizeof(int8_t);
if (!handled && preciseScan)
{
// Push something unknown to the stack since we couldn't find anything useful for inlining
pushedStack.PushUnknown();
}
handled = false;
DECODE_OPCODE:
if ((unsigned)opcode >= CEE_COUNT)
{
BADCODE3("Illegal opcode", ": %02X", (int)opcode);
}
if ((opcode >= CEE_LDARG_0 && opcode <= CEE_STLOC_S) || (opcode >= CEE_LDARG && opcode <= CEE_STLOC))
{
opts.lvRefCount++;
}
if (makeInlineObservations && (opcode >= CEE_LDNULL) && (opcode <= CEE_LDC_R8))
{
// LDTOKEN and LDSTR are handled below
pushedStack.PushConstant();
handled = true;
}
unsigned sz = opcodeSizes[opcode];
switch (opcode)
{
case CEE_PREFIX1:
{
if (codeAddr >= codeEndp)
{
goto TOO_FAR;
}
opcode = (OPCODE)(256 + getU1LittleEndian(codeAddr));
codeAddr += sizeof(int8_t);
goto DECODE_OPCODE;
}
case CEE_PREFIX2:
case CEE_PREFIX3:
case CEE_PREFIX4:
case CEE_PREFIX5: