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llvm-project/clang/lib/CodeGen/CodeGenPGO.cpp
Akira Hatanaka 8bd1f9116a
[CodeGen][arm64e] Add methods and data members to Address, which are needed to authenticate signed pointers (#67454) 
To authenticate pointers, CodeGen needs access to the key and
discriminators that were used to sign the pointer. That information is
sometimes known from the context, but not always, which is why `Address`
needs to hold that information.

This patch adds methods and data members to `Address`, which will be
needed in subsequent patches to authenticate signed pointers, and uses
the newly added methods throughout CodeGen. Although this patch isn't
strictly NFC as it causes CodeGen to use different code paths in some
cases (e.g., `mergeAddressesInConditionalExpr`), it doesn't cause any
changes in functionality as it doesn't add any information needed for
authentication.

In addition to the changes mentioned above, this patch introduces class
`RawAddress`, which contains a pointer that we know is unsigned, and
adds several new functions for creating `Address` and `LValue` objects.
2024-03-25 18:05:42 -07:00

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//===--- CodeGenPGO.cpp - PGO Instrumentation for LLVM CodeGen --*- C++ -*-===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//
//
// Instrumentation-based profile-guided optimization
//
//===----------------------------------------------------------------------===//
#include "CodeGenPGO.h"
#include "CodeGenFunction.h"
#include "CoverageMappingGen.h"
#include "clang/AST/RecursiveASTVisitor.h"
#include "clang/AST/StmtVisitor.h"
#include "llvm/IR/Intrinsics.h"
#include "llvm/IR/MDBuilder.h"
#include "llvm/Support/CommandLine.h"
#include "llvm/Support/Endian.h"
#include "llvm/Support/FileSystem.h"
#include "llvm/Support/MD5.h"
#include <optional>
namespace llvm {
extern cl::opt<bool> EnableSingleByteCoverage;
} // namespace llvm
static llvm::cl::opt<bool>
EnableValueProfiling("enable-value-profiling",
llvm::cl::desc("Enable value profiling"),
llvm::cl::Hidden, llvm::cl::init(false));
extern llvm::cl::opt<bool> SystemHeadersCoverage;
using namespace clang;
using namespace CodeGen;
void CodeGenPGO::setFuncName(StringRef Name,
llvm::GlobalValue::LinkageTypes Linkage) {
llvm::IndexedInstrProfReader *PGOReader = CGM.getPGOReader();
FuncName = llvm::getPGOFuncName(
Name, Linkage, CGM.getCodeGenOpts().MainFileName,
PGOReader ? PGOReader->getVersion() : llvm::IndexedInstrProf::Version);
// If we're generating a profile, create a variable for the name.
if (CGM.getCodeGenOpts().hasProfileClangInstr())
FuncNameVar = llvm::createPGOFuncNameVar(CGM.getModule(), Linkage, FuncName);
}
void CodeGenPGO::setFuncName(llvm::Function *Fn) {
setFuncName(Fn->getName(), Fn->getLinkage());
// Create PGOFuncName meta data.
llvm::createPGOFuncNameMetadata(*Fn, FuncName);
}
/// The version of the PGO hash algorithm.
enum PGOHashVersion : unsigned {
PGO_HASH_V1,
PGO_HASH_V2,
PGO_HASH_V3,
// Keep this set to the latest hash version.
PGO_HASH_LATEST = PGO_HASH_V3
};
namespace {
/// Stable hasher for PGO region counters.
///
/// PGOHash produces a stable hash of a given function's control flow.
///
/// Changing the output of this hash will invalidate all previously generated
/// profiles -- i.e., don't do it.
///
/// \note When this hash does eventually change (years?), we still need to
/// support old hashes. We'll need to pull in the version number from the
/// profile data format and use the matching hash function.
class PGOHash {
uint64_t Working;
unsigned Count;
PGOHashVersion HashVersion;
llvm::MD5 MD5;
static const int NumBitsPerType = 6;
static const unsigned NumTypesPerWord = sizeof(uint64_t) * 8 / NumBitsPerType;
static const unsigned TooBig = 1u << NumBitsPerType;
public:
/// Hash values for AST nodes.
///
/// Distinct values for AST nodes that have region counters attached.
///
/// These values must be stable. All new members must be added at the end,
/// and no members should be removed. Changing the enumeration value for an
/// AST node will affect the hash of every function that contains that node.
enum HashType : unsigned char {
None = 0,
LabelStmt = 1,
WhileStmt,
DoStmt,
ForStmt,
CXXForRangeStmt,
ObjCForCollectionStmt,
SwitchStmt,
CaseStmt,
DefaultStmt,
IfStmt,
CXXTryStmt,
CXXCatchStmt,
ConditionalOperator,
BinaryOperatorLAnd,
BinaryOperatorLOr,
BinaryConditionalOperator,
// The preceding values are available with PGO_HASH_V1.
EndOfScope,
IfThenBranch,
IfElseBranch,
GotoStmt,
IndirectGotoStmt,
BreakStmt,
ContinueStmt,
ReturnStmt,
ThrowExpr,
UnaryOperatorLNot,
BinaryOperatorLT,
BinaryOperatorGT,
BinaryOperatorLE,
BinaryOperatorGE,
BinaryOperatorEQ,
BinaryOperatorNE,
// The preceding values are available since PGO_HASH_V2.
// Keep this last. It's for the static assert that follows.
LastHashType
};
static_assert(LastHashType <= TooBig, "Too many types in HashType");
PGOHash(PGOHashVersion HashVersion)
: Working(0), Count(0), HashVersion(HashVersion) {}
void combine(HashType Type);
uint64_t finalize();
PGOHashVersion getHashVersion() const { return HashVersion; }
};
const int PGOHash::NumBitsPerType;
const unsigned PGOHash::NumTypesPerWord;
const unsigned PGOHash::TooBig;
/// Get the PGO hash version used in the given indexed profile.
static PGOHashVersion getPGOHashVersion(llvm::IndexedInstrProfReader *PGOReader,
CodeGenModule &CGM) {
if (PGOReader->getVersion() <= 4)
return PGO_HASH_V1;
if (PGOReader->getVersion() <= 5)
return PGO_HASH_V2;
return PGO_HASH_V3;
}
/// A RecursiveASTVisitor that fills a map of statements to PGO counters.
struct MapRegionCounters : public RecursiveASTVisitor<MapRegionCounters> {
using Base = RecursiveASTVisitor<MapRegionCounters>;
/// The next counter value to assign.
unsigned NextCounter;
/// The function hash.
PGOHash Hash;
/// The map of statements to counters.
llvm::DenseMap<const Stmt *, unsigned> &CounterMap;
/// The next bitmap byte index to assign.
unsigned NextMCDCBitmapIdx;
/// The state of MC/DC Coverage in this function.
MCDC::State &MCDCState;
/// Maximum number of supported MC/DC conditions in a boolean expression.
unsigned MCDCMaxCond;
/// The profile version.
uint64_t ProfileVersion;
/// Diagnostics Engine used to report warnings.
DiagnosticsEngine &Diag;
MapRegionCounters(PGOHashVersion HashVersion, uint64_t ProfileVersion,
llvm::DenseMap<const Stmt *, unsigned> &CounterMap,
MCDC::State &MCDCState, unsigned MCDCMaxCond,
DiagnosticsEngine &Diag)
: NextCounter(0), Hash(HashVersion), CounterMap(CounterMap),
NextMCDCBitmapIdx(0), MCDCState(MCDCState), MCDCMaxCond(MCDCMaxCond),
ProfileVersion(ProfileVersion), Diag(Diag) {}
// Blocks and lambdas are handled as separate functions, so we need not
// traverse them in the parent context.
bool TraverseBlockExpr(BlockExpr *BE) { return true; }
bool TraverseLambdaExpr(LambdaExpr *LE) {
// Traverse the captures, but not the body.
for (auto C : zip(LE->captures(), LE->capture_inits()))
TraverseLambdaCapture(LE, &std::get<0>(C), std::get<1>(C));
return true;
}
bool TraverseCapturedStmt(CapturedStmt *CS) { return true; }
bool VisitDecl(const Decl *D) {
switch (D->getKind()) {
default:
break;
case Decl::Function:
case Decl::CXXMethod:
case Decl::CXXConstructor:
case Decl::CXXDestructor:
case Decl::CXXConversion:
case Decl::ObjCMethod:
case Decl::Block:
case Decl::Captured:
CounterMap[D->getBody()] = NextCounter++;
break;
}
return true;
}
/// If \p S gets a fresh counter, update the counter mappings. Return the
/// V1 hash of \p S.
PGOHash::HashType updateCounterMappings(Stmt *S) {
auto Type = getHashType(PGO_HASH_V1, S);
if (Type != PGOHash::None)
CounterMap[S] = NextCounter++;
return Type;
}
/// The following stacks are used with dataTraverseStmtPre() and
/// dataTraverseStmtPost() to track the depth of nested logical operators in a
/// boolean expression in a function. The ultimate purpose is to keep track
/// of the number of leaf-level conditions in the boolean expression so that a
/// profile bitmap can be allocated based on that number.
///
/// The stacks are also used to find error cases and notify the user. A
/// standard logical operator nest for a boolean expression could be in a form
/// similar to this: "x = a && b && c && (d || f)"
unsigned NumCond = 0;
bool SplitNestedLogicalOp = false;
SmallVector<const Stmt *, 16> NonLogOpStack;
SmallVector<const BinaryOperator *, 16> LogOpStack;
// Hook: dataTraverseStmtPre() is invoked prior to visiting an AST Stmt node.
bool dataTraverseStmtPre(Stmt *S) {
/// If MC/DC is not enabled, MCDCMaxCond will be set to 0. Do nothing.
if (MCDCMaxCond == 0)
return true;
/// At the top of the logical operator nest, reset the number of conditions,
/// also forget previously seen split nesting cases.
if (LogOpStack.empty()) {
NumCond = 0;
SplitNestedLogicalOp = false;
}
if (const Expr *E = dyn_cast<Expr>(S)) {
const BinaryOperator *BinOp = dyn_cast<BinaryOperator>(E->IgnoreParens());
if (BinOp && BinOp->isLogicalOp()) {
/// Check for "split-nested" logical operators. This happens when a new
/// boolean expression logical-op nest is encountered within an existing
/// boolean expression, separated by a non-logical operator. For
/// example, in "x = (a && b && c && foo(d && f))", the "d && f" case
/// starts a new boolean expression that is separated from the other
/// conditions by the operator foo(). Split-nested cases are not
/// supported by MC/DC.
SplitNestedLogicalOp = SplitNestedLogicalOp || !NonLogOpStack.empty();
LogOpStack.push_back(BinOp);
return true;
}
}
/// Keep track of non-logical operators. These are OK as long as we don't
/// encounter a new logical operator after seeing one.
if (!LogOpStack.empty())
NonLogOpStack.push_back(S);
return true;
}
// Hook: dataTraverseStmtPost() is invoked by the AST visitor after visiting
// an AST Stmt node. MC/DC will use it to to signal when the top of a
// logical operation (boolean expression) nest is encountered.
bool dataTraverseStmtPost(Stmt *S) {
/// If MC/DC is not enabled, MCDCMaxCond will be set to 0. Do nothing.
if (MCDCMaxCond == 0)
return true;
if (const Expr *E = dyn_cast<Expr>(S)) {
const BinaryOperator *BinOp = dyn_cast<BinaryOperator>(E->IgnoreParens());
if (BinOp && BinOp->isLogicalOp()) {
assert(LogOpStack.back() == BinOp);
LogOpStack.pop_back();
/// At the top of logical operator nest:
if (LogOpStack.empty()) {
/// Was the "split-nested" logical operator case encountered?
if (SplitNestedLogicalOp) {
unsigned DiagID = Diag.getCustomDiagID(
DiagnosticsEngine::Warning,
"unsupported MC/DC boolean expression; "
"contains an operation with a nested boolean expression. "
"Expression will not be covered");
Diag.Report(S->getBeginLoc(), DiagID);
return true;
}
/// Was the maximum number of conditions encountered?
if (NumCond > MCDCMaxCond) {
unsigned DiagID = Diag.getCustomDiagID(
DiagnosticsEngine::Warning,
"unsupported MC/DC boolean expression; "
"number of conditions (%0) exceeds max (%1). "
"Expression will not be covered");
Diag.Report(S->getBeginLoc(), DiagID) << NumCond << MCDCMaxCond;
return true;
}
// Otherwise, allocate the number of bytes required for the bitmap
// based on the number of conditions. Must be at least 1-byte long.
MCDCState.DecisionByStmt[BinOp].BitmapIdx = NextMCDCBitmapIdx;
unsigned SizeInBits = std::max<unsigned>(1L << NumCond, CHAR_BIT);
NextMCDCBitmapIdx += SizeInBits / CHAR_BIT;
}
return true;
}
}
if (!LogOpStack.empty())
NonLogOpStack.pop_back();
return true;
}
/// The RHS of all logical operators gets a fresh counter in order to count
/// how many times the RHS evaluates to true or false, depending on the
/// semantics of the operator. This is only valid for ">= v7" of the profile
/// version so that we facilitate backward compatibility. In addition, in
/// order to use MC/DC, count the number of total LHS and RHS conditions.
bool VisitBinaryOperator(BinaryOperator *S) {
if (S->isLogicalOp()) {
if (CodeGenFunction::isInstrumentedCondition(S->getLHS()))
NumCond++;
if (CodeGenFunction::isInstrumentedCondition(S->getRHS())) {
if (ProfileVersion >= llvm::IndexedInstrProf::Version7)
CounterMap[S->getRHS()] = NextCounter++;
NumCond++;
}
}
return Base::VisitBinaryOperator(S);
}
bool VisitConditionalOperator(ConditionalOperator *S) {
if (llvm::EnableSingleByteCoverage && S->getTrueExpr())
CounterMap[S->getTrueExpr()] = NextCounter++;
if (llvm::EnableSingleByteCoverage && S->getFalseExpr())
CounterMap[S->getFalseExpr()] = NextCounter++;
return Base::VisitConditionalOperator(S);
}
/// Include \p S in the function hash.
bool VisitStmt(Stmt *S) {
auto Type = updateCounterMappings(S);
if (Hash.getHashVersion() != PGO_HASH_V1)
Type = getHashType(Hash.getHashVersion(), S);
if (Type != PGOHash::None)
Hash.combine(Type);
return true;
}
bool TraverseIfStmt(IfStmt *If) {
// If we used the V1 hash, use the default traversal.
if (Hash.getHashVersion() == PGO_HASH_V1)
return Base::TraverseIfStmt(If);
// When single byte coverage mode is enabled, add a counter to then and
// else.
bool NoSingleByteCoverage = !llvm::EnableSingleByteCoverage;
for (Stmt *CS : If->children()) {
if (!CS || NoSingleByteCoverage)
continue;
if (CS == If->getThen())
CounterMap[If->getThen()] = NextCounter++;
else if (CS == If->getElse())
CounterMap[If->getElse()] = NextCounter++;
}
// Otherwise, keep track of which branch we're in while traversing.
VisitStmt(If);
for (Stmt *CS : If->children()) {
if (!CS)
continue;
if (CS == If->getThen())
Hash.combine(PGOHash::IfThenBranch);
else if (CS == If->getElse())
Hash.combine(PGOHash::IfElseBranch);
TraverseStmt(CS);
}
Hash.combine(PGOHash::EndOfScope);
return true;
}
bool TraverseWhileStmt(WhileStmt *While) {
// When single byte coverage mode is enabled, add a counter to condition and
// body.
bool NoSingleByteCoverage = !llvm::EnableSingleByteCoverage;
for (Stmt *CS : While->children()) {
if (!CS || NoSingleByteCoverage)
continue;
if (CS == While->getCond())
CounterMap[While->getCond()] = NextCounter++;
else if (CS == While->getBody())
CounterMap[While->getBody()] = NextCounter++;
}
Base::TraverseWhileStmt(While);
if (Hash.getHashVersion() != PGO_HASH_V1)
Hash.combine(PGOHash::EndOfScope);
return true;
}
bool TraverseDoStmt(DoStmt *Do) {
// When single byte coverage mode is enabled, add a counter to condition and
// body.
bool NoSingleByteCoverage = !llvm::EnableSingleByteCoverage;
for (Stmt *CS : Do->children()) {
if (!CS || NoSingleByteCoverage)
continue;
if (CS == Do->getCond())
CounterMap[Do->getCond()] = NextCounter++;
else if (CS == Do->getBody())
CounterMap[Do->getBody()] = NextCounter++;
}
Base::TraverseDoStmt(Do);
if (Hash.getHashVersion() != PGO_HASH_V1)
Hash.combine(PGOHash::EndOfScope);
return true;
}
bool TraverseForStmt(ForStmt *For) {
// When single byte coverage mode is enabled, add a counter to condition,
// increment and body.
bool NoSingleByteCoverage = !llvm::EnableSingleByteCoverage;
for (Stmt *CS : For->children()) {
if (!CS || NoSingleByteCoverage)
continue;
if (CS == For->getCond())
CounterMap[For->getCond()] = NextCounter++;
else if (CS == For->getInc())
CounterMap[For->getInc()] = NextCounter++;
else if (CS == For->getBody())
CounterMap[For->getBody()] = NextCounter++;
}
Base::TraverseForStmt(For);
if (Hash.getHashVersion() != PGO_HASH_V1)
Hash.combine(PGOHash::EndOfScope);
return true;
}
bool TraverseCXXForRangeStmt(CXXForRangeStmt *ForRange) {
// When single byte coverage mode is enabled, add a counter to body.
bool NoSingleByteCoverage = !llvm::EnableSingleByteCoverage;
for (Stmt *CS : ForRange->children()) {
if (!CS || NoSingleByteCoverage)
continue;
if (CS == ForRange->getBody())
CounterMap[ForRange->getBody()] = NextCounter++;
}
Base::TraverseCXXForRangeStmt(ForRange);
if (Hash.getHashVersion() != PGO_HASH_V1)
Hash.combine(PGOHash::EndOfScope);
return true;
}
// If the statement type \p N is nestable, and its nesting impacts profile
// stability, define a custom traversal which tracks the end of the statement
// in the hash (provided we're not using the V1 hash).
#define DEFINE_NESTABLE_TRAVERSAL(N) \
bool Traverse##N(N *S) { \
Base::Traverse##N(S); \
if (Hash.getHashVersion() != PGO_HASH_V1) \
Hash.combine(PGOHash::EndOfScope); \
return true; \
}
DEFINE_NESTABLE_TRAVERSAL(ObjCForCollectionStmt)
DEFINE_NESTABLE_TRAVERSAL(CXXTryStmt)
DEFINE_NESTABLE_TRAVERSAL(CXXCatchStmt)
/// Get version \p HashVersion of the PGO hash for \p S.
PGOHash::HashType getHashType(PGOHashVersion HashVersion, const Stmt *S) {
switch (S->getStmtClass()) {
default:
break;
case Stmt::LabelStmtClass:
return PGOHash::LabelStmt;
case Stmt::WhileStmtClass:
return PGOHash::WhileStmt;
case Stmt::DoStmtClass:
return PGOHash::DoStmt;
case Stmt::ForStmtClass:
return PGOHash::ForStmt;
case Stmt::CXXForRangeStmtClass:
return PGOHash::CXXForRangeStmt;
case Stmt::ObjCForCollectionStmtClass:
return PGOHash::ObjCForCollectionStmt;
case Stmt::SwitchStmtClass:
return PGOHash::SwitchStmt;
case Stmt::CaseStmtClass:
return PGOHash::CaseStmt;
case Stmt::DefaultStmtClass:
return PGOHash::DefaultStmt;
case Stmt::IfStmtClass:
return PGOHash::IfStmt;
case Stmt::CXXTryStmtClass:
return PGOHash::CXXTryStmt;
case Stmt::CXXCatchStmtClass:
return PGOHash::CXXCatchStmt;
case Stmt::ConditionalOperatorClass:
return PGOHash::ConditionalOperator;
case Stmt::BinaryConditionalOperatorClass:
return PGOHash::BinaryConditionalOperator;
case Stmt::BinaryOperatorClass: {
const BinaryOperator *BO = cast<BinaryOperator>(S);
if (BO->getOpcode() == BO_LAnd)
return PGOHash::BinaryOperatorLAnd;
if (BO->getOpcode() == BO_LOr)
return PGOHash::BinaryOperatorLOr;
if (HashVersion >= PGO_HASH_V2) {
switch (BO->getOpcode()) {
default:
break;
case BO_LT:
return PGOHash::BinaryOperatorLT;
case BO_GT:
return PGOHash::BinaryOperatorGT;
case BO_LE:
return PGOHash::BinaryOperatorLE;
case BO_GE:
return PGOHash::BinaryOperatorGE;
case BO_EQ:
return PGOHash::BinaryOperatorEQ;
case BO_NE:
return PGOHash::BinaryOperatorNE;
}
}
break;
}
}
if (HashVersion >= PGO_HASH_V2) {
switch (S->getStmtClass()) {
default:
break;
case Stmt::GotoStmtClass:
return PGOHash::GotoStmt;
case Stmt::IndirectGotoStmtClass:
return PGOHash::IndirectGotoStmt;
case Stmt::BreakStmtClass:
return PGOHash::BreakStmt;
case Stmt::ContinueStmtClass:
return PGOHash::ContinueStmt;
case Stmt::ReturnStmtClass:
return PGOHash::ReturnStmt;
case Stmt::CXXThrowExprClass:
return PGOHash::ThrowExpr;
case Stmt::UnaryOperatorClass: {
const UnaryOperator *UO = cast<UnaryOperator>(S);
if (UO->getOpcode() == UO_LNot)
return PGOHash::UnaryOperatorLNot;
break;
}
}
}
return PGOHash::None;
}
};
/// A StmtVisitor that propagates the raw counts through the AST and
/// records the count at statements where the value may change.
struct ComputeRegionCounts : public ConstStmtVisitor<ComputeRegionCounts> {
/// PGO state.
CodeGenPGO &PGO;
/// A flag that is set when the current count should be recorded on the
/// next statement, such as at the exit of a loop.
bool RecordNextStmtCount;
/// The count at the current location in the traversal.
uint64_t CurrentCount;
/// The map of statements to count values.
llvm::DenseMap<const Stmt *, uint64_t> &CountMap;
/// BreakContinueStack - Keep counts of breaks and continues inside loops.
struct BreakContinue {
uint64_t BreakCount = 0;
uint64_t ContinueCount = 0;
BreakContinue() = default;
};
SmallVector<BreakContinue, 8> BreakContinueStack;
ComputeRegionCounts(llvm::DenseMap<const Stmt *, uint64_t> &CountMap,
CodeGenPGO &PGO)
: PGO(PGO), RecordNextStmtCount(false), CountMap(CountMap) {}
void RecordStmtCount(const Stmt *S) {
if (RecordNextStmtCount) {
CountMap[S] = CurrentCount;
RecordNextStmtCount = false;
}
}
/// Set and return the current count.
uint64_t setCount(uint64_t Count) {
CurrentCount = Count;
return Count;
}
void VisitStmt(const Stmt *S) {
RecordStmtCount(S);
for (const Stmt *Child : S->children())
if (Child)
this->Visit(Child);
}
void VisitFunctionDecl(const FunctionDecl *D) {
// Counter tracks entry to the function body.
uint64_t BodyCount = setCount(PGO.getRegionCount(D->getBody()));
CountMap[D->getBody()] = BodyCount;
Visit(D->getBody());
}
// Skip lambda expressions. We visit these as FunctionDecls when we're
// generating them and aren't interested in the body when generating a
// parent context.
void VisitLambdaExpr(const LambdaExpr *LE) {}
void VisitCapturedDecl(const CapturedDecl *D) {
// Counter tracks entry to the capture body.
uint64_t BodyCount = setCount(PGO.getRegionCount(D->getBody()));
CountMap[D->getBody()] = BodyCount;
Visit(D->getBody());
}
void VisitObjCMethodDecl(const ObjCMethodDecl *D) {
// Counter tracks entry to the method body.
uint64_t BodyCount = setCount(PGO.getRegionCount(D->getBody()));
CountMap[D->getBody()] = BodyCount;
Visit(D->getBody());
}
void VisitBlockDecl(const BlockDecl *D) {
// Counter tracks entry to the block body.
uint64_t BodyCount = setCount(PGO.getRegionCount(D->getBody()));
CountMap[D->getBody()] = BodyCount;
Visit(D->getBody());
}
void VisitReturnStmt(const ReturnStmt *S) {
RecordStmtCount(S);
if (S->getRetValue())
Visit(S->getRetValue());
CurrentCount = 0;
RecordNextStmtCount = true;
}
void VisitCXXThrowExpr(const CXXThrowExpr *E) {
RecordStmtCount(E);
if (E->getSubExpr())
Visit(E->getSubExpr());
CurrentCount = 0;
RecordNextStmtCount = true;
}
void VisitGotoStmt(const GotoStmt *S) {
RecordStmtCount(S);
CurrentCount = 0;
RecordNextStmtCount = true;
}
void VisitLabelStmt(const LabelStmt *S) {
RecordNextStmtCount = false;
// Counter tracks the block following the label.
uint64_t BlockCount = setCount(PGO.getRegionCount(S));
CountMap[S] = BlockCount;
Visit(S->getSubStmt());
}
void VisitBreakStmt(const BreakStmt *S) {
RecordStmtCount(S);
assert(!BreakContinueStack.empty() && "break not in a loop or switch!");
BreakContinueStack.back().BreakCount += CurrentCount;
CurrentCount = 0;
RecordNextStmtCount = true;
}
void VisitContinueStmt(const ContinueStmt *S) {
RecordStmtCount(S);
assert(!BreakContinueStack.empty() && "continue stmt not in a loop!");
BreakContinueStack.back().ContinueCount += CurrentCount;
CurrentCount = 0;
RecordNextStmtCount = true;
}
void VisitWhileStmt(const WhileStmt *S) {
RecordStmtCount(S);
uint64_t ParentCount = CurrentCount;
BreakContinueStack.push_back(BreakContinue());
// Visit the body region first so the break/continue adjustments can be
// included when visiting the condition.
uint64_t BodyCount = setCount(PGO.getRegionCount(S));
CountMap[S->getBody()] = CurrentCount;
Visit(S->getBody());
uint64_t BackedgeCount = CurrentCount;
// ...then go back and propagate counts through the condition. The count
// at the start of the condition is the sum of the incoming edges,
// the backedge from the end of the loop body, and the edges from
// continue statements.
BreakContinue BC = BreakContinueStack.pop_back_val();
uint64_t CondCount =
setCount(ParentCount + BackedgeCount + BC.ContinueCount);
CountMap[S->getCond()] = CondCount;
Visit(S->getCond());
setCount(BC.BreakCount + CondCount - BodyCount);
RecordNextStmtCount = true;
}
void VisitDoStmt(const DoStmt *S) {
RecordStmtCount(S);
uint64_t LoopCount = PGO.getRegionCount(S);
BreakContinueStack.push_back(BreakContinue());
// The count doesn't include the fallthrough from the parent scope. Add it.
uint64_t BodyCount = setCount(LoopCount + CurrentCount);
CountMap[S->getBody()] = BodyCount;
Visit(S->getBody());
uint64_t BackedgeCount = CurrentCount;
BreakContinue BC = BreakContinueStack.pop_back_val();
// The count at the start of the condition is equal to the count at the
// end of the body, plus any continues.
uint64_t CondCount = setCount(BackedgeCount + BC.ContinueCount);
CountMap[S->getCond()] = CondCount;
Visit(S->getCond());
setCount(BC.BreakCount + CondCount - LoopCount);
RecordNextStmtCount = true;
}
void VisitForStmt(const ForStmt *S) {
RecordStmtCount(S);
if (S->getInit())
Visit(S->getInit());
uint64_t ParentCount = CurrentCount;
BreakContinueStack.push_back(BreakContinue());
// Visit the body region first. (This is basically the same as a while
// loop; see further comments in VisitWhileStmt.)
uint64_t BodyCount = setCount(PGO.getRegionCount(S));
CountMap[S->getBody()] = BodyCount;
Visit(S->getBody());
uint64_t BackedgeCount = CurrentCount;
BreakContinue BC = BreakContinueStack.pop_back_val();
// The increment is essentially part of the body but it needs to include
// the count for all the continue statements.
if (S->getInc()) {
uint64_t IncCount = setCount(BackedgeCount + BC.ContinueCount);
CountMap[S->getInc()] = IncCount;
Visit(S->getInc());
}
// ...then go back and propagate counts through the condition.
uint64_t CondCount =
setCount(ParentCount + BackedgeCount + BC.ContinueCount);
if (S->getCond()) {
CountMap[S->getCond()] = CondCount;
Visit(S->getCond());
}
setCount(BC.BreakCount + CondCount - BodyCount);
RecordNextStmtCount = true;
}
void VisitCXXForRangeStmt(const CXXForRangeStmt *S) {
RecordStmtCount(S);
if (S->getInit())
Visit(S->getInit());
Visit(S->getLoopVarStmt());
Visit(S->getRangeStmt());
Visit(S->getBeginStmt());
Visit(S->getEndStmt());
uint64_t ParentCount = CurrentCount;
BreakContinueStack.push_back(BreakContinue());
// Visit the body region first. (This is basically the same as a while
// loop; see further comments in VisitWhileStmt.)
uint64_t BodyCount = setCount(PGO.getRegionCount(S));
CountMap[S->getBody()] = BodyCount;
Visit(S->getBody());
uint64_t BackedgeCount = CurrentCount;
BreakContinue BC = BreakContinueStack.pop_back_val();
// The increment is essentially part of the body but it needs to include
// the count for all the continue statements.
uint64_t IncCount = setCount(BackedgeCount + BC.ContinueCount);
CountMap[S->getInc()] = IncCount;
Visit(S->getInc());
// ...then go back and propagate counts through the condition.
uint64_t CondCount =
setCount(ParentCount + BackedgeCount + BC.ContinueCount);
CountMap[S->getCond()] = CondCount;
Visit(S->getCond());
setCount(BC.BreakCount + CondCount - BodyCount);
RecordNextStmtCount = true;
}
void VisitObjCForCollectionStmt(const ObjCForCollectionStmt *S) {
RecordStmtCount(S);
Visit(S->getElement());
uint64_t ParentCount = CurrentCount;
BreakContinueStack.push_back(BreakContinue());
// Counter tracks the body of the loop.
uint64_t BodyCount = setCount(PGO.getRegionCount(S));
CountMap[S->getBody()] = BodyCount;
Visit(S->getBody());
uint64_t BackedgeCount = CurrentCount;
BreakContinue BC = BreakContinueStack.pop_back_val();
setCount(BC.BreakCount + ParentCount + BackedgeCount + BC.ContinueCount -
BodyCount);
RecordNextStmtCount = true;
}
void VisitSwitchStmt(const SwitchStmt *S) {
RecordStmtCount(S);
if (S->getInit())
Visit(S->getInit());
Visit(S->getCond());
CurrentCount = 0;
BreakContinueStack.push_back(BreakContinue());
Visit(S->getBody());
// If the switch is inside a loop, add the continue counts.
BreakContinue BC = BreakContinueStack.pop_back_val();
if (!BreakContinueStack.empty())
BreakContinueStack.back().ContinueCount += BC.ContinueCount;
// Counter tracks the exit block of the switch.
setCount(PGO.getRegionCount(S));
RecordNextStmtCount = true;
}
void VisitSwitchCase(const SwitchCase *S) {
RecordNextStmtCount = false;
// Counter for this particular case. This counts only jumps from the
// switch header and does not include fallthrough from the case before
// this one.
uint64_t CaseCount = PGO.getRegionCount(S);
setCount(CurrentCount + CaseCount);
// We need the count without fallthrough in the mapping, so it's more useful
// for branch probabilities.
CountMap[S] = CaseCount;
RecordNextStmtCount = true;
Visit(S->getSubStmt());
}
void VisitIfStmt(const IfStmt *S) {
RecordStmtCount(S);
if (S->isConsteval()) {
const Stmt *Stm = S->isNegatedConsteval() ? S->getThen() : S->getElse();
if (Stm)
Visit(Stm);
return;
}
uint64_t ParentCount = CurrentCount;
if (S->getInit())
Visit(S->getInit());
Visit(S->getCond());
// Counter tracks the "then" part of an if statement. The count for
// the "else" part, if it exists, will be calculated from this counter.
uint64_t ThenCount = setCount(PGO.getRegionCount(S));
CountMap[S->getThen()] = ThenCount;
Visit(S->getThen());
uint64_t OutCount = CurrentCount;
uint64_t ElseCount = ParentCount - ThenCount;
if (S->getElse()) {
setCount(ElseCount);
CountMap[S->getElse()] = ElseCount;
Visit(S->getElse());
OutCount += CurrentCount;
} else
OutCount += ElseCount;
setCount(OutCount);
RecordNextStmtCount = true;
}
void VisitCXXTryStmt(const CXXTryStmt *S) {
RecordStmtCount(S);
Visit(S->getTryBlock());
for (unsigned I = 0, E = S->getNumHandlers(); I < E; ++I)
Visit(S->getHandler(I));
// Counter tracks the continuation block of the try statement.
setCount(PGO.getRegionCount(S));
RecordNextStmtCount = true;
}
void VisitCXXCatchStmt(const CXXCatchStmt *S) {
RecordNextStmtCount = false;
// Counter tracks the catch statement's handler block.
uint64_t CatchCount = setCount(PGO.getRegionCount(S));
CountMap[S] = CatchCount;
Visit(S->getHandlerBlock());
}
void VisitAbstractConditionalOperator(const AbstractConditionalOperator *E) {
RecordStmtCount(E);
uint64_t ParentCount = CurrentCount;
Visit(E->getCond());
// Counter tracks the "true" part of a conditional operator. The
// count in the "false" part will be calculated from this counter.
uint64_t TrueCount = setCount(PGO.getRegionCount(E));
CountMap[E->getTrueExpr()] = TrueCount;
Visit(E->getTrueExpr());
uint64_t OutCount = CurrentCount;
uint64_t FalseCount = setCount(ParentCount - TrueCount);
CountMap[E->getFalseExpr()] = FalseCount;
Visit(E->getFalseExpr());
OutCount += CurrentCount;
setCount(OutCount);
RecordNextStmtCount = true;
}
void VisitBinLAnd(const BinaryOperator *E) {
RecordStmtCount(E);
uint64_t ParentCount = CurrentCount;
Visit(E->getLHS());
// Counter tracks the right hand side of a logical and operator.
uint64_t RHSCount = setCount(PGO.getRegionCount(E));
CountMap[E->getRHS()] = RHSCount;
Visit(E->getRHS());
setCount(ParentCount + RHSCount - CurrentCount);
RecordNextStmtCount = true;
}
void VisitBinLOr(const BinaryOperator *E) {
RecordStmtCount(E);
uint64_t ParentCount = CurrentCount;
Visit(E->getLHS());
// Counter tracks the right hand side of a logical or operator.
uint64_t RHSCount = setCount(PGO.getRegionCount(E));
CountMap[E->getRHS()] = RHSCount;
Visit(E->getRHS());
setCount(ParentCount + RHSCount - CurrentCount);
RecordNextStmtCount = true;
}
};
} // end anonymous namespace
void PGOHash::combine(HashType Type) {
// Check that we never combine 0 and only have six bits.
assert(Type && "Hash is invalid: unexpected type 0");
assert(unsigned(Type) < TooBig && "Hash is invalid: too many types");
// Pass through MD5 if enough work has built up.
if (Count && Count % NumTypesPerWord == 0) {
using namespace llvm::support;
uint64_t Swapped =
endian::byte_swap<uint64_t, llvm::endianness::little>(Working);
MD5.update(llvm::ArrayRef((uint8_t *)&Swapped, sizeof(Swapped)));
Working = 0;
}
// Accumulate the current type.
++Count;
Working = Working << NumBitsPerType | Type;
}
uint64_t PGOHash::finalize() {
// Use Working as the hash directly if we never used MD5.
if (Count <= NumTypesPerWord)
// No need to byte swap here, since none of the math was endian-dependent.
// This number will be byte-swapped as required on endianness transitions,
// so we will see the same value on the other side.
return Working;
// Check for remaining work in Working.
if (Working) {
// Keep the buggy behavior from v1 and v2 for backward-compatibility. This
// is buggy because it converts a uint64_t into an array of uint8_t.
if (HashVersion < PGO_HASH_V3) {
MD5.update({(uint8_t)Working});
} else {
using namespace llvm::support;
uint64_t Swapped =
endian::byte_swap<uint64_t, llvm::endianness::little>(Working);
MD5.update(llvm::ArrayRef((uint8_t *)&Swapped, sizeof(Swapped)));
}
}
// Finalize the MD5 and return the hash.
llvm::MD5::MD5Result Result;
MD5.final(Result);
return Result.low();
}
void CodeGenPGO::assignRegionCounters(GlobalDecl GD, llvm::Function *Fn) {
const Decl *D = GD.getDecl();
if (!D->hasBody())
return;
// Skip CUDA/HIP kernel launch stub functions.
if (CGM.getLangOpts().CUDA && !CGM.getLangOpts().CUDAIsDevice &&
D->hasAttr<CUDAGlobalAttr>())
return;
bool InstrumentRegions = CGM.getCodeGenOpts().hasProfileClangInstr();
llvm::IndexedInstrProfReader *PGOReader = CGM.getPGOReader();
if (!InstrumentRegions && !PGOReader)
return;
if (D->isImplicit())
return;
// Constructors and destructors may be represented by several functions in IR.
// If so, instrument only base variant, others are implemented by delegation
// to the base one, it would be counted twice otherwise.
if (CGM.getTarget().getCXXABI().hasConstructorVariants()) {
if (const auto *CCD = dyn_cast<CXXConstructorDecl>(D))
if (GD.getCtorType() != Ctor_Base &&
CodeGenFunction::IsConstructorDelegationValid(CCD))
return;
}
if (isa<CXXDestructorDecl>(D) && GD.getDtorType() != Dtor_Base)
return;
CGM.ClearUnusedCoverageMapping(D);
if (Fn->hasFnAttribute(llvm::Attribute::NoProfile))
return;
if (Fn->hasFnAttribute(llvm::Attribute::SkipProfile))
return;
setFuncName(Fn);
mapRegionCounters(D);
if (CGM.getCodeGenOpts().CoverageMapping)
emitCounterRegionMapping(D);
if (PGOReader) {
SourceManager &SM = CGM.getContext().getSourceManager();
loadRegionCounts(PGOReader, SM.isInMainFile(D->getLocation()));
computeRegionCounts(D);
applyFunctionAttributes(PGOReader, Fn);
}
}
void CodeGenPGO::mapRegionCounters(const Decl *D) {
// Use the latest hash version when inserting instrumentation, but use the
// version in the indexed profile if we're reading PGO data.
PGOHashVersion HashVersion = PGO_HASH_LATEST;
uint64_t ProfileVersion = llvm::IndexedInstrProf::Version;
if (auto *PGOReader = CGM.getPGOReader()) {
HashVersion = getPGOHashVersion(PGOReader, CGM);
ProfileVersion = PGOReader->getVersion();
}
// If MC/DC is enabled, set the MaxConditions to a preset value. Otherwise,
// set it to zero. This value impacts the number of conditions accepted in a
// given boolean expression, which impacts the size of the bitmap used to
// track test vector execution for that boolean expression. Because the
// bitmap scales exponentially (2^n) based on the number of conditions seen,
// the maximum value is hard-coded at 6 conditions, which is more than enough
// for most embedded applications. Setting a maximum value prevents the
// bitmap footprint from growing too large without the user's knowledge. In
// the future, this value could be adjusted with a command-line option.
unsigned MCDCMaxConditions = (CGM.getCodeGenOpts().MCDCCoverage) ? 6 : 0;
RegionCounterMap.reset(new llvm::DenseMap<const Stmt *, unsigned>);
RegionMCDCState.reset(new MCDC::State);
MapRegionCounters Walker(HashVersion, ProfileVersion, *RegionCounterMap,
*RegionMCDCState, MCDCMaxConditions, CGM.getDiags());
if (const FunctionDecl *FD = dyn_cast_or_null<FunctionDecl>(D))
Walker.TraverseDecl(const_cast<FunctionDecl *>(FD));
else if (const ObjCMethodDecl *MD = dyn_cast_or_null<ObjCMethodDecl>(D))
Walker.TraverseDecl(const_cast<ObjCMethodDecl *>(MD));
else if (const BlockDecl *BD = dyn_cast_or_null<BlockDecl>(D))
Walker.TraverseDecl(const_cast<BlockDecl *>(BD));
else if (const CapturedDecl *CD = dyn_cast_or_null<CapturedDecl>(D))
Walker.TraverseDecl(const_cast<CapturedDecl *>(CD));
assert(Walker.NextCounter > 0 && "no entry counter mapped for decl");
NumRegionCounters = Walker.NextCounter;
RegionMCDCState->BitmapBytes = Walker.NextMCDCBitmapIdx;
FunctionHash = Walker.Hash.finalize();
}
bool CodeGenPGO::skipRegionMappingForDecl(const Decl *D) {
if (!D->getBody())
return true;
// Skip host-only functions in the CUDA device compilation and device-only
// functions in the host compilation. Just roughly filter them out based on
// the function attributes. If there are effectively host-only or device-only
// ones, their coverage mapping may still be generated.
if (CGM.getLangOpts().CUDA &&
((CGM.getLangOpts().CUDAIsDevice && !D->hasAttr<CUDADeviceAttr>() &&
!D->hasAttr<CUDAGlobalAttr>()) ||
(!CGM.getLangOpts().CUDAIsDevice &&
(D->hasAttr<CUDAGlobalAttr>() ||
(!D->hasAttr<CUDAHostAttr>() && D->hasAttr<CUDADeviceAttr>())))))
return true;
// Don't map the functions in system headers.
const auto &SM = CGM.getContext().getSourceManager();
auto Loc = D->getBody()->getBeginLoc();
return !SystemHeadersCoverage && SM.isInSystemHeader(Loc);
}
void CodeGenPGO::emitCounterRegionMapping(const Decl *D) {
if (skipRegionMappingForDecl(D))
return;
std::string CoverageMapping;
llvm::raw_string_ostream OS(CoverageMapping);
RegionMCDCState->BranchByStmt.clear();
CoverageMappingGen MappingGen(
*CGM.getCoverageMapping(), CGM.getContext().getSourceManager(),
CGM.getLangOpts(), RegionCounterMap.get(), RegionMCDCState.get());
MappingGen.emitCounterMapping(D, OS);
OS.flush();
if (CoverageMapping.empty())
return;
CGM.getCoverageMapping()->addFunctionMappingRecord(
FuncNameVar, FuncName, FunctionHash, CoverageMapping);
}
void
CodeGenPGO::emitEmptyCounterMapping(const Decl *D, StringRef Name,
llvm::GlobalValue::LinkageTypes Linkage) {
if (skipRegionMappingForDecl(D))
return;
std::string CoverageMapping;
llvm::raw_string_ostream OS(CoverageMapping);
CoverageMappingGen MappingGen(*CGM.getCoverageMapping(),
CGM.getContext().getSourceManager(),
CGM.getLangOpts());
MappingGen.emitEmptyMapping(D, OS);
OS.flush();
if (CoverageMapping.empty())
return;
setFuncName(Name, Linkage);
CGM.getCoverageMapping()->addFunctionMappingRecord(
FuncNameVar, FuncName, FunctionHash, CoverageMapping, false);
}
void CodeGenPGO::computeRegionCounts(const Decl *D) {
StmtCountMap.reset(new llvm::DenseMap<const Stmt *, uint64_t>);
ComputeRegionCounts Walker(*StmtCountMap, *this);
if (const FunctionDecl *FD = dyn_cast_or_null<FunctionDecl>(D))
Walker.VisitFunctionDecl(FD);
else if (const ObjCMethodDecl *MD = dyn_cast_or_null<ObjCMethodDecl>(D))
Walker.VisitObjCMethodDecl(MD);
else if (const BlockDecl *BD = dyn_cast_or_null<BlockDecl>(D))
Walker.VisitBlockDecl(BD);
else if (const CapturedDecl *CD = dyn_cast_or_null<CapturedDecl>(D))
Walker.VisitCapturedDecl(const_cast<CapturedDecl *>(CD));
}
void
CodeGenPGO::applyFunctionAttributes(llvm::IndexedInstrProfReader *PGOReader,
llvm::Function *Fn) {
if (!haveRegionCounts())
return;
uint64_t FunctionCount = getRegionCount(nullptr);
Fn->setEntryCount(FunctionCount);
}
void CodeGenPGO::emitCounterSetOrIncrement(CGBuilderTy &Builder, const Stmt *S,
llvm::Value *StepV) {
if (!RegionCounterMap || !Builder.GetInsertBlock())
return;
unsigned Counter = (*RegionCounterMap)[S];
llvm::Value *Args[] = {FuncNameVar,
Builder.getInt64(FunctionHash),
Builder.getInt32(NumRegionCounters),
Builder.getInt32(Counter), StepV};
if (llvm::EnableSingleByteCoverage)
Builder.CreateCall(CGM.getIntrinsic(llvm::Intrinsic::instrprof_cover),
ArrayRef(Args, 4));
else {
if (!StepV)
Builder.CreateCall(CGM.getIntrinsic(llvm::Intrinsic::instrprof_increment),
ArrayRef(Args, 4));
else
Builder.CreateCall(
CGM.getIntrinsic(llvm::Intrinsic::instrprof_increment_step),
ArrayRef(Args));
}
}
bool CodeGenPGO::canEmitMCDCCoverage(const CGBuilderTy &Builder) {
return (CGM.getCodeGenOpts().hasProfileClangInstr() &&
CGM.getCodeGenOpts().MCDCCoverage && Builder.GetInsertBlock());
}
void CodeGenPGO::emitMCDCParameters(CGBuilderTy &Builder) {
if (!canEmitMCDCCoverage(Builder) || !RegionMCDCState)
return;
auto *I8PtrTy = llvm::PointerType::getUnqual(CGM.getLLVMContext());
// Emit intrinsic representing MCDC bitmap parameters at function entry.
// This is used by the instrumentation pass, but it isn't actually lowered to
// anything.
llvm::Value *Args[3] = {llvm::ConstantExpr::getBitCast(FuncNameVar, I8PtrTy),
Builder.getInt64(FunctionHash),
Builder.getInt32(RegionMCDCState->BitmapBytes)};
Builder.CreateCall(
CGM.getIntrinsic(llvm::Intrinsic::instrprof_mcdc_parameters), Args);
}
void CodeGenPGO::emitMCDCTestVectorBitmapUpdate(CGBuilderTy &Builder,
const Expr *S,
Address MCDCCondBitmapAddr,
CodeGenFunction &CGF) {
if (!canEmitMCDCCoverage(Builder) || !RegionMCDCState)
return;
S = S->IgnoreParens();
auto DecisionStateIter = RegionMCDCState->DecisionByStmt.find(S);
if (DecisionStateIter == RegionMCDCState->DecisionByStmt.end())
return;
// Extract the offset of the global bitmap associated with this expression.
unsigned MCDCTestVectorBitmapOffset = DecisionStateIter->second.BitmapIdx;
auto *I8PtrTy = llvm::PointerType::getUnqual(CGM.getLLVMContext());
// Emit intrinsic responsible for updating the global bitmap corresponding to
// a boolean expression. The index being set is based on the value loaded
// from a pointer to a dedicated temporary value on the stack that is itself
// updated via emitMCDCCondBitmapReset() and emitMCDCCondBitmapUpdate(). The
// index represents an executed test vector.
llvm::Value *Args[5] = {llvm::ConstantExpr::getBitCast(FuncNameVar, I8PtrTy),
Builder.getInt64(FunctionHash),
Builder.getInt32(RegionMCDCState->BitmapBytes),
Builder.getInt32(MCDCTestVectorBitmapOffset),
MCDCCondBitmapAddr.emitRawPointer(CGF)};
Builder.CreateCall(
CGM.getIntrinsic(llvm::Intrinsic::instrprof_mcdc_tvbitmap_update), Args);
}
void CodeGenPGO::emitMCDCCondBitmapReset(CGBuilderTy &Builder, const Expr *S,
Address MCDCCondBitmapAddr) {
if (!canEmitMCDCCoverage(Builder) || !RegionMCDCState)
return;
S = S->IgnoreParens();
if (!RegionMCDCState->DecisionByStmt.contains(S))
return;
// Emit intrinsic that resets a dedicated temporary value on the stack to 0.
Builder.CreateStore(Builder.getInt32(0), MCDCCondBitmapAddr);
}
void CodeGenPGO::emitMCDCCondBitmapUpdate(CGBuilderTy &Builder, const Expr *S,
Address MCDCCondBitmapAddr,
llvm::Value *Val,
CodeGenFunction &CGF) {
if (!canEmitMCDCCoverage(Builder) || !RegionMCDCState)
return;
// Even though, for simplicity, parentheses and unary logical-NOT operators
// are considered part of their underlying condition for both MC/DC and
// branch coverage, the condition IDs themselves are assigned and tracked
// using the underlying condition itself. This is done solely for
// consistency since parentheses and logical-NOTs are ignored when checking
// whether the condition is actually an instrumentable condition. This can
// also make debugging a bit easier.
S = CodeGenFunction::stripCond(S);
auto BranchStateIter = RegionMCDCState->BranchByStmt.find(S);
if (BranchStateIter == RegionMCDCState->BranchByStmt.end())
return;
// Extract the ID of the condition we are setting in the bitmap.
const auto &Branch = BranchStateIter->second;
assert(Branch.ID >= 0 && "Condition has no ID!");
auto *I8PtrTy = llvm::PointerType::getUnqual(CGM.getLLVMContext());
// Emit intrinsic that updates a dedicated temporary value on the stack after
// a condition is evaluated. After the set of conditions has been updated,
// the resulting value is used to update the boolean expression's bitmap.
llvm::Value *Args[5] = {llvm::ConstantExpr::getBitCast(FuncNameVar, I8PtrTy),
Builder.getInt64(FunctionHash),
Builder.getInt32(Branch.ID),
MCDCCondBitmapAddr.emitRawPointer(CGF), Val};
Builder.CreateCall(
CGM.getIntrinsic(llvm::Intrinsic::instrprof_mcdc_condbitmap_update),
Args);
}
void CodeGenPGO::setValueProfilingFlag(llvm::Module &M) {
if (CGM.getCodeGenOpts().hasProfileClangInstr())
M.addModuleFlag(llvm::Module::Warning, "EnableValueProfiling",
uint32_t(EnableValueProfiling));
}
void CodeGenPGO::setProfileVersion(llvm::Module &M) {
if (CGM.getCodeGenOpts().hasProfileClangInstr() &&
llvm::EnableSingleByteCoverage) {
const StringRef VarName(INSTR_PROF_QUOTE(INSTR_PROF_RAW_VERSION_VAR));
llvm::Type *IntTy64 = llvm::Type::getInt64Ty(M.getContext());
uint64_t ProfileVersion =
(INSTR_PROF_RAW_VERSION | VARIANT_MASK_BYTE_COVERAGE);
auto IRLevelVersionVariable = new llvm::GlobalVariable(
M, IntTy64, true, llvm::GlobalValue::WeakAnyLinkage,
llvm::Constant::getIntegerValue(IntTy64,
llvm::APInt(64, ProfileVersion)),
VarName);
IRLevelVersionVariable->setVisibility(llvm::GlobalValue::DefaultVisibility);
llvm::Triple TT(M.getTargetTriple());
if (TT.supportsCOMDAT()) {
IRLevelVersionVariable->setLinkage(llvm::GlobalValue::ExternalLinkage);
IRLevelVersionVariable->setComdat(M.getOrInsertComdat(VarName));
}
IRLevelVersionVariable->setDSOLocal(true);
}
}
// This method either inserts a call to the profile run-time during
// instrumentation or puts profile data into metadata for PGO use.
void CodeGenPGO::valueProfile(CGBuilderTy &Builder, uint32_t ValueKind,
llvm::Instruction *ValueSite, llvm::Value *ValuePtr) {
if (!EnableValueProfiling)
return;
if (!ValuePtr || !ValueSite || !Builder.GetInsertBlock())
return;
if (isa<llvm::Constant>(ValuePtr))
return;
bool InstrumentValueSites = CGM.getCodeGenOpts().hasProfileClangInstr();
if (InstrumentValueSites && RegionCounterMap) {
auto BuilderInsertPoint = Builder.saveIP();
Builder.SetInsertPoint(ValueSite);
llvm::Value *Args[5] = {
FuncNameVar,
Builder.getInt64(FunctionHash),
Builder.CreatePtrToInt(ValuePtr, Builder.getInt64Ty()),
Builder.getInt32(ValueKind),
Builder.getInt32(NumValueSites[ValueKind]++)
};
Builder.CreateCall(
CGM.getIntrinsic(llvm::Intrinsic::instrprof_value_profile), Args);
Builder.restoreIP(BuilderInsertPoint);
return;
}
llvm::IndexedInstrProfReader *PGOReader = CGM.getPGOReader();
if (PGOReader && haveRegionCounts()) {
// We record the top most called three functions at each call site.
// Profile metadata contains "VP" string identifying this metadata
// as value profiling data, then a uint32_t value for the value profiling
// kind, a uint64_t value for the total number of times the call is
// executed, followed by the function hash and execution count (uint64_t)
// pairs for each function.
if (NumValueSites[ValueKind] >= ProfRecord->getNumValueSites(ValueKind))
return;
llvm::annotateValueSite(CGM.getModule(), *ValueSite, *ProfRecord,
(llvm::InstrProfValueKind)ValueKind,
NumValueSites[ValueKind]);
NumValueSites[ValueKind]++;
}
}
void CodeGenPGO::loadRegionCounts(llvm::IndexedInstrProfReader *PGOReader,
bool IsInMainFile) {
CGM.getPGOStats().addVisited(IsInMainFile);
RegionCounts.clear();
llvm::Expected<llvm::InstrProfRecord> RecordExpected =
PGOReader->getInstrProfRecord(FuncName, FunctionHash);
if (auto E = RecordExpected.takeError()) {
auto IPE = std::get<0>(llvm::InstrProfError::take(std::move(E)));
if (IPE == llvm::instrprof_error::unknown_function)
CGM.getPGOStats().addMissing(IsInMainFile);
else if (IPE == llvm::instrprof_error::hash_mismatch)
CGM.getPGOStats().addMismatched(IsInMainFile);
else if (IPE == llvm::instrprof_error::malformed)
// TODO: Consider a more specific warning for this case.
CGM.getPGOStats().addMismatched(IsInMainFile);
return;
}
ProfRecord =
std::make_unique<llvm::InstrProfRecord>(std::move(RecordExpected.get()));
RegionCounts = ProfRecord->Counts;
}
/// Calculate what to divide by to scale weights.
///
/// Given the maximum weight, calculate a divisor that will scale all the
/// weights to strictly less than UINT32_MAX.
static uint64_t calculateWeightScale(uint64_t MaxWeight) {
return MaxWeight < UINT32_MAX ? 1 : MaxWeight / UINT32_MAX + 1;
}
/// Scale an individual branch weight (and add 1).
///
/// Scale a 64-bit weight down to 32-bits using \c Scale.
///
/// According to Laplace's Rule of Succession, it is better to compute the
/// weight based on the count plus 1, so universally add 1 to the value.
///
/// \pre \c Scale was calculated by \a calculateWeightScale() with a weight no
/// greater than \c Weight.
static uint32_t scaleBranchWeight(uint64_t Weight, uint64_t Scale) {
assert(Scale && "scale by 0?");
uint64_t Scaled = Weight / Scale + 1;
assert(Scaled <= UINT32_MAX && "overflow 32-bits");
return Scaled;
}
llvm::MDNode *CodeGenFunction::createProfileWeights(uint64_t TrueCount,
uint64_t FalseCount) const {
// Check for empty weights.
if (!TrueCount && !FalseCount)
return nullptr;
// Calculate how to scale down to 32-bits.
uint64_t Scale = calculateWeightScale(std::max(TrueCount, FalseCount));
llvm::MDBuilder MDHelper(CGM.getLLVMContext());
return MDHelper.createBranchWeights(scaleBranchWeight(TrueCount, Scale),
scaleBranchWeight(FalseCount, Scale));
}
llvm::MDNode *
CodeGenFunction::createProfileWeights(ArrayRef<uint64_t> Weights) const {
// We need at least two elements to create meaningful weights.
if (Weights.size() < 2)
return nullptr;
// Check for empty weights.
uint64_t MaxWeight = *std::max_element(Weights.begin(), Weights.end());
if (MaxWeight == 0)
return nullptr;
// Calculate how to scale down to 32-bits.
uint64_t Scale = calculateWeightScale(MaxWeight);
SmallVector<uint32_t, 16> ScaledWeights;
ScaledWeights.reserve(Weights.size());
for (uint64_t W : Weights)
ScaledWeights.push_back(scaleBranchWeight(W, Scale));
llvm::MDBuilder MDHelper(CGM.getLLVMContext());
return MDHelper.createBranchWeights(ScaledWeights);
}
llvm::MDNode *
CodeGenFunction::createProfileWeightsForLoop(const Stmt *Cond,
uint64_t LoopCount) const {
if (!PGO.haveRegionCounts())
return nullptr;
std::optional<uint64_t> CondCount = PGO.getStmtCount(Cond);
if (!CondCount || *CondCount == 0)
return nullptr;
return createProfileWeights(LoopCount,
std::max(*CondCount, LoopCount) - LoopCount);
}
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