Tyker updated this revision to Diff 192012.
CHANGES SINCE LAST ACTION
https://reviews.llvm.org/D59467/new/
https://reviews.llvm.org/D59467
Files:
clang/include/clang/AST/Stmt.h
clang/include/clang/Basic/Attr.td
clang/include/clang/Basic/AttrDocs.td
clang/include/clang/Basic/DiagnosticSemaKinds.td
clang/include/clang/Sema/Scope.h
clang/include/clang/Sema/Sema.h
clang/lib/AST/Stmt.cpp
clang/lib/CodeGen/CGStmt.cpp
clang/lib/CodeGen/CodeGenFunction.cpp
clang/lib/CodeGen/CodeGenFunction.h
clang/lib/Parse/ParseStmt.cpp
clang/lib/Sema/Scope.cpp
clang/lib/Sema/SemaStmt.cpp
clang/lib/Sema/SemaStmtAttr.cpp
clang/lib/Serialization/ASTReaderStmt.cpp
clang/lib/Serialization/ASTWriterStmt.cpp
Index: clang/lib/Serialization/ASTWriterStmt.cpp
===================================================================
--- clang/lib/Serialization/ASTWriterStmt.cpp
+++ clang/lib/Serialization/ASTWriterStmt.cpp
@@ -139,6 +139,7 @@
Record.push_back(HasElse);
Record.push_back(HasVar);
Record.push_back(HasInit);
+ Record.push_back(S->getBranchHint());
Record.AddStmt(S->getCond());
Record.AddStmt(S->getThen());
Index: clang/lib/Serialization/ASTReaderStmt.cpp
===================================================================
--- clang/lib/Serialization/ASTReaderStmt.cpp
+++ clang/lib/Serialization/ASTReaderStmt.cpp
@@ -222,6 +222,7 @@
bool HasElse = Record.readInt();
bool HasVar = Record.readInt();
bool HasInit = Record.readInt();
+ S->setBranchHint(static_cast<BranchHint>(Record.readInt()));
S->setCond(Record.readSubExpr());
S->setThen(Record.readSubStmt());
Index: clang/lib/Sema/SemaStmtAttr.cpp
===================================================================
--- clang/lib/Sema/SemaStmtAttr.cpp
+++ clang/lib/Sema/SemaStmtAttr.cpp
@@ -51,6 +51,46 @@
return ::new (S.Context) auto(Attr);
}
+static Attr *handleLikelihoodAttr(Sema &S, Stmt *St, const ParsedAttr &A,
+ SourceRange Range) {
+ Attr *Attr = ::new (S.Context) LikelihoodAttr(
+ A.getRange(), S.Context, A.getAttributeSpellingListIndex());
+
+ if (!S.getLangOpts().CPlusPlus2a && A.isCXX11Attribute())
+ S.Diag(A.getLoc(), diag::ext_cxx2a_attr) << A.getName();
+
+ Scope *CurScope = S.getCurScope();
+
+ if (CurScope) {
+ Scope *ControlScope = CurScope->getParent();
+ if (!ControlScope ||
+ !(ControlScope->getFlags() & Scope::ControlScope ||
+ ControlScope->getFlags() & Scope::BreakScope) ||
+ ControlScope->getFlags() & Scope::SEHExceptScope ||
+ ControlScope->getFlags() & Scope::SEHTryScope ||
+ ControlScope->getFlags() & Scope::TryScope ||
+ ControlScope->getFlags() & Scope::FnTryCatchScope) {
+ S.Diag(A.getLoc(), diag::warn_no_associated_branch) << A.getName();
+ return Attr;
+ }
+
+ if (ControlScope->getBranchAttr()) {
+ if (ControlScope->getBranchAttr()->getSpelling()[0] ==
+ Attr->getSpelling()[0])
+ S.Diag(Attr->getLocation(), diag::err_repeat_attribute)
+ << Attr->getSpelling();
+ else
+ S.Diag(Attr->getLocation(), diag::err_attributes_are_not_compatible)
+ << Attr->getSpelling()
+ << ControlScope->getBranchAttr()->getSpelling();
+ S.Diag(ControlScope->getBranchAttr()->getLocation(),
+ diag::note_previous_attribute);
+ } else
+ ControlScope->setBranchAttr(Attr);
+ }
+ return Attr;
+}
+
static Attr *handleSuppressAttr(Sema &S, Stmt *St, const ParsedAttr &A,
SourceRange Range) {
if (A.getNumArgs() < 1) {
@@ -336,6 +376,8 @@
return nullptr;
case ParsedAttr::AT_FallThrough:
return handleFallThroughAttr(S, St, A, Range);
+ case ParsedAttr::AT_Likelihood:
+ return handleLikelihoodAttr(S, St, A, Range);
case ParsedAttr::AT_LoopHint:
return handleLoopHintAttr(S, St, A, Range);
case ParsedAttr::AT_OpenCLUnrollHint:
Index: clang/lib/Sema/SemaStmt.cpp
===================================================================
--- clang/lib/Sema/SemaStmt.cpp
+++ clang/lib/Sema/SemaStmt.cpp
@@ -521,11 +521,48 @@
};
}
-StmtResult
-Sema::ActOnIfStmt(SourceLocation IfLoc, bool IsConstexpr, Stmt *InitStmt,
- ConditionResult Cond,
- Stmt *thenStmt, SourceLocation ElseLoc,
- Stmt *elseStmt) {
+BranchHint Sema::HandleIfStmtHint(Stmt *thenStmt, Stmt *elseStmt,
+ Attr *ThenAttr, Attr *ElseAttr) {
+ // diagnose branch with attribute and null statement as empty body
+ if (thenStmt && isa<AttributedStmt>(thenStmt) &&
+ isa<NullStmt>(dyn_cast<AttributedStmt>(thenStmt)->getSubStmt()))
+ DiagnoseEmptyStmtBody(
+ dyn_cast<AttributedStmt>(thenStmt)->getSubStmt()->getBeginLoc(),
+ dyn_cast<AttributedStmt>(thenStmt)->getSubStmt(),
+ diag::warn_empty_if_body);
+ if (elseStmt && isa<AttributedStmt>(elseStmt) &&
+ isa<NullStmt>(dyn_cast<AttributedStmt>(elseStmt)->getSubStmt()))
+ DiagnoseEmptyStmtBody(
+ dyn_cast<AttributedStmt>(elseStmt)->getSubStmt()->getBeginLoc(),
+ dyn_cast<AttributedStmt>(elseStmt)->getSubStmt(),
+ diag::warn_empty_if_body);
+
+ BranchHint Hint = NoHint;
+ // diagnose conflicting attribute and determinate hint
+ if (ThenAttr) {
+ if (ElseAttr && ThenAttr->getSpelling()[0] == ElseAttr->getSpelling()[0]) {
+ Diag(ElseAttr->getLocation(), diag::warn_conflicting_attribute)
+ << ElseAttr->getSpelling() << ThenAttr->getSpelling();
+ Diag(ThenAttr->getLocation(), diag::note_conflicting_attribute);
+ } else {
+ if (ThenAttr->getSpelling()[0] == 'l')
+ Hint = Taken;
+ else
+ Hint = NotTaken;
+ }
+ } else if (ElseAttr) {
+ if (ElseAttr->getSpelling()[0] == 'u')
+ Hint = Taken;
+ else
+ Hint = NotTaken;
+ }
+ return Hint;
+}
+
+StmtResult Sema::ActOnIfStmt(SourceLocation IfLoc, bool IsConstexpr,
+ Stmt *InitStmt, ConditionResult Cond,
+ Stmt *thenStmt, SourceLocation ElseLoc,
+ Stmt *elseStmt, Attr *ThenAttr, Attr *ElseAttr) {
if (Cond.isInvalid())
Cond = ConditionResult(
*this, nullptr,
@@ -545,13 +582,14 @@
diag::warn_empty_if_body);
return BuildIfStmt(IfLoc, IsConstexpr, InitStmt, Cond, thenStmt, ElseLoc,
- elseStmt);
+ elseStmt,
+ HandleIfStmtHint(thenStmt, elseStmt, ThenAttr, ElseAttr));
}
StmtResult Sema::BuildIfStmt(SourceLocation IfLoc, bool IsConstexpr,
Stmt *InitStmt, ConditionResult Cond,
Stmt *thenStmt, SourceLocation ElseLoc,
- Stmt *elseStmt) {
+ Stmt *elseStmt, BranchHint Hint) {
if (Cond.isInvalid())
return StmtError();
@@ -559,7 +597,7 @@
setFunctionHasBranchProtectedScope();
return IfStmt::Create(Context, IfLoc, IsConstexpr, InitStmt, Cond.get().first,
- Cond.get().second, thenStmt, ElseLoc, elseStmt);
+ Cond.get().second, thenStmt, ElseLoc, elseStmt, Hint);
}
namespace {
Index: clang/lib/Sema/Scope.cpp
===================================================================
--- clang/lib/Sema/Scope.cpp
+++ clang/lib/Sema/Scope.cpp
@@ -87,6 +87,7 @@
void Scope::Init(Scope *parent, unsigned flags) {
setFlags(parent, flags);
+ BranchAttr = 0;
DeclsInScope.clear();
UsingDirectives.clear();
Entity = nullptr;
Index: clang/lib/Parse/ParseStmt.cpp
===================================================================
--- clang/lib/Parse/ParseStmt.cpp
+++ clang/lib/Parse/ParseStmt.cpp
@@ -19,6 +19,7 @@
#include "clang/Parse/RAIIObjectsForParser.h"
#include "clang/Sema/DeclSpec.h"
#include "clang/Sema/Scope.h"
+#include "clang/Sema/SemaDiagnostic.h"
#include "clang/Sema/TypoCorrection.h"
using namespace clang;
@@ -1256,6 +1257,9 @@
// Pop the 'if' scope if needed.
InnerScope.Exit();
+ Attr *ThenAttr = getCurScope()->getBranchAttr();
+ getCurScope()->setBranchAttr(nullptr);
+
// If it has an else, parse it.
SourceLocation ElseLoc;
SourceLocation ElseStmtLoc;
@@ -1295,6 +1299,7 @@
} else if (InnerStatementTrailingElseLoc.isValid()) {
Diag(InnerStatementTrailingElseLoc, diag::warn_dangling_else);
}
+ Attr *ElseAttr = getCurScope()->getBranchAttr();
IfScope.Exit();
@@ -1315,7 +1320,8 @@
ElseStmt = Actions.ActOnNullStmt(ElseStmtLoc);
return Actions.ActOnIfStmt(IfLoc, IsConstexpr, InitStmt.get(), Cond,
- ThenStmt.get(), ElseLoc, ElseStmt.get());
+ ThenStmt.get(), ElseLoc, ElseStmt.get(), ThenAttr,
+ ElseAttr);
}
/// ParseSwitchStatement
Index: clang/lib/CodeGen/CodeGenFunction.h
===================================================================
--- clang/lib/CodeGen/CodeGenFunction.h
+++ clang/lib/CodeGen/CodeGenFunction.h
@@ -2852,6 +2852,8 @@
AggValueSlot AVS =
AggValueSlot::ignored());
+ void MaybeEmitLikelihoodHint(const Stmt *branch, llvm::Value *CondV);
+
/// EmitLabel - Emit the block for the given label. It is legal to call this
/// function even if there is no current insertion point.
void EmitLabel(const LabelDecl *D); // helper for EmitLabelStmt.
@@ -4041,7 +4043,8 @@
/// TrueCount should be the number of times we expect the condition to
/// evaluate to true based on PGO data.
void EmitBranchOnBoolExpr(const Expr *Cond, llvm::BasicBlock *TrueBlock,
- llvm::BasicBlock *FalseBlock, uint64_t TrueCount);
+ llvm::BasicBlock *FalseBlock, uint64_t TrueCount,
+ BranchHint hint = NoHint);
/// Given an assignment `*LHS = RHS`, emit a test that checks if \p RHS is
/// nonnull, if \p LHS is marked _Nonnull.
Index: clang/lib/CodeGen/CodeGenFunction.cpp
===================================================================
--- clang/lib/CodeGen/CodeGenFunction.cpp
+++ clang/lib/CodeGen/CodeGenFunction.cpp
@@ -1531,7 +1531,8 @@
void CodeGenFunction::EmitBranchOnBoolExpr(const Expr *Cond,
llvm::BasicBlock *TrueBlock,
llvm::BasicBlock *FalseBlock,
- uint64_t TrueCount) {
+ uint64_t TrueCount,
+ BranchHint Hint) {
Cond = Cond->IgnoreParens();
if (const BinaryOperator *CondBOp = dyn_cast<BinaryOperator>(Cond)) {
@@ -1720,6 +1721,14 @@
ApplyDebugLocation DL(*this, Cond);
CondV = EvaluateExprAsBool(Cond);
}
+
+ if (Hint != NoHint && CGM.getCodeGenOpts().OptimizationLevel != 0) {
+ llvm::Constant *ExpectedValue = llvm::ConstantInt::get(
+ llvm::Type::getInt1Ty(this->getLLVMContext()), Hint == Taken);
+ llvm::Function *FnExpect =
+ CGM.getIntrinsic(llvm::Intrinsic::expect, CondV->getType());
+ Builder.CreateCall(FnExpect, {CondV, ExpectedValue}, "expval");
+ }
Builder.CreateCondBr(CondV, TrueBlock, FalseBlock, Weights, Unpredictable);
}
Index: clang/lib/CodeGen/CGStmt.cpp
===================================================================
--- clang/lib/CodeGen/CGStmt.cpp
+++ clang/lib/CodeGen/CGStmt.cpp
@@ -658,7 +658,7 @@
ElseBlock = createBasicBlock("if.else");
EmitBranchOnBoolExpr(S.getCond(), ThenBlock, ElseBlock,
- getProfileCount(S.getThen()));
+ getProfileCount(S.getThen()), S.getBranchHint());
// Emit the 'then' code.
EmitBlock(ThenBlock);
@@ -691,6 +691,18 @@
EmitBlock(ContBlock, true);
}
+void CodeGenFunction::MaybeEmitLikelihoodHint(const Stmt *branch,
+ llvm::Value *CondV) {
+ BranchHint hint = NoHint;
+ if (hint != NoHint && CGM.getCodeGenOpts().OptimizationLevel != 0) {
+ llvm::Constant *ExpectedValue = llvm::ConstantInt::get(
+ llvm::Type::getInt1Ty(this->getLLVMContext()), hint == Taken);
+ llvm::Function *FnExpect =
+ CGM.getIntrinsic(llvm::Intrinsic::expect, CondV->getType());
+ Builder.CreateCall(FnExpect, {CondV, ExpectedValue}, "expval");
+ }
+}
+
void CodeGenFunction::EmitWhileStmt(const WhileStmt &S,
ArrayRef<const Attr *> WhileAttrs) {
// Emit the header for the loop, which will also become
@@ -740,6 +752,7 @@
llvm::BasicBlock *ExitBlock = LoopExit.getBlock();
if (ConditionScope.requiresCleanups())
ExitBlock = createBasicBlock("while.exit");
+ MaybeEmitLikelihoodHint(S.getBody(), BoolCondVal);
Builder.CreateCondBr(
BoolCondVal, LoopBody, ExitBlock,
createProfileWeightsForLoop(S.getCond(), getProfileCount(S.getBody())));
@@ -825,6 +838,7 @@
// As long as the condition is true, iterate the loop.
if (EmitBoolCondBranch) {
uint64_t BackedgeCount = getProfileCount(S.getBody()) - ParentCount;
+ MaybeEmitLikelihoodHint(S.getBody(), BoolCondVal);
Builder.CreateCondBr(
BoolCondVal, LoopBody, LoopExit.getBlock(),
createProfileWeightsForLoop(S.getCond(), BackedgeCount));
@@ -895,6 +909,7 @@
// C99 6.8.5p2/p4: The first substatement is executed if the expression
// compares unequal to 0. The condition must be a scalar type.
llvm::Value *BoolCondVal = EvaluateExprAsBool(S.getCond());
+ MaybeEmitLikelihoodHint(S.getBody(), BoolCondVal);
Builder.CreateCondBr(
BoolCondVal, ForBody, ExitBlock,
createProfileWeightsForLoop(S.getCond(), getProfileCount(S.getBody())));
@@ -976,6 +991,7 @@
// The body is executed if the expression, contextually converted
// to bool, is true.
llvm::Value *BoolCondVal = EvaluateExprAsBool(S.getCond());
+ MaybeEmitLikelihoodHint(S.getBody(), BoolCondVal);
Builder.CreateCondBr(
BoolCondVal, ForBody, ExitBlock,
createProfileWeightsForLoop(S.getCond(), getProfileCount(S.getBody())));
Index: clang/lib/AST/Stmt.cpp
===================================================================
--- clang/lib/AST/Stmt.cpp
+++ clang/lib/AST/Stmt.cpp
@@ -798,7 +798,7 @@
IfStmt::IfStmt(const ASTContext &Ctx, SourceLocation IL, bool IsConstexpr,
Stmt *Init, VarDecl *Var, Expr *Cond, Stmt *Then,
- SourceLocation EL, Stmt *Else)
+ SourceLocation EL, Stmt *Else, BranchHint Hint)
: Stmt(IfStmtClass) {
bool HasElse = Else != nullptr;
bool HasVar = Var != nullptr;
@@ -806,6 +806,7 @@
IfStmtBits.HasElse = HasElse;
IfStmtBits.HasVar = HasVar;
IfStmtBits.HasInit = HasInit;
+ IfStmtBits.Hint = Hint;
setConstexpr(IsConstexpr);
@@ -828,11 +829,13 @@
IfStmtBits.HasElse = HasElse;
IfStmtBits.HasVar = HasVar;
IfStmtBits.HasInit = HasInit;
+ IfStmtBits.Hint = NoHint;
}
IfStmt *IfStmt::Create(const ASTContext &Ctx, SourceLocation IL,
bool IsConstexpr, Stmt *Init, VarDecl *Var, Expr *Cond,
- Stmt *Then, SourceLocation EL, Stmt *Else) {
+ Stmt *Then, SourceLocation EL, Stmt *Else,
+ BranchHint Hint) {
bool HasElse = Else != nullptr;
bool HasVar = Var != nullptr;
bool HasInit = Init != nullptr;
@@ -841,7 +844,7 @@
NumMandatoryStmtPtr + HasElse + HasVar + HasInit, HasElse),
alignof(IfStmt));
return new (Mem)
- IfStmt(Ctx, IL, IsConstexpr, Init, Var, Cond, Then, EL, Else);
+ IfStmt(Ctx, IL, IsConstexpr, Init, Var, Cond, Then, EL, Else, Hint);
}
IfStmt *IfStmt::CreateEmpty(const ASTContext &Ctx, bool HasElse, bool HasVar,
Index: clang/include/clang/Sema/Sema.h
===================================================================
--- clang/include/clang/Sema/Sema.h
+++ clang/include/clang/Sema/Sema.h
@@ -3841,14 +3841,18 @@
Stmt *SubStmt);
class ConditionResult;
- StmtResult ActOnIfStmt(SourceLocation IfLoc, bool IsConstexpr,
- Stmt *InitStmt,
+ /// emit diagnostics and determinate the hint for and If statement
+ BranchHint HandleIfStmtHint(Stmt *thenStmt, Stmt *elseStmt, Attr *ThenAttr,
+ Attr *ElseAttr);
+
+ StmtResult ActOnIfStmt(SourceLocation IfLoc, bool IsConstexpr, Stmt *InitStmt,
ConditionResult Cond, Stmt *ThenVal,
- SourceLocation ElseLoc, Stmt *ElseVal);
- StmtResult BuildIfStmt(SourceLocation IfLoc, bool IsConstexpr,
- Stmt *InitStmt,
+ SourceLocation ElseLoc, Stmt *ElseVal,
+ Attr *ThenAttr = nullptr, Attr *ElseAttr = nullptr);
+ StmtResult BuildIfStmt(SourceLocation IfLoc, bool IsConstexpr, Stmt *InitStmt,
ConditionResult Cond, Stmt *ThenVal,
- SourceLocation ElseLoc, Stmt *ElseVal);
+ SourceLocation ElseLoc, Stmt *ElseVal,
+ BranchHint Hint = NoHint);
StmtResult ActOnStartOfSwitchStmt(SourceLocation SwitchLoc,
Stmt *InitStmt,
ConditionResult Cond);
Index: clang/include/clang/Sema/Scope.h
===================================================================
--- clang/include/clang/Sema/Scope.h
+++ clang/include/clang/Sema/Scope.h
@@ -160,6 +160,9 @@
/// declared in this scope.
unsigned short PrototypeIndex;
+ /// BranchAttr - Likelihood attribute associated with this Branch or nullptr
+ Attr *BranchAttr;
+
/// FnParent - If this scope has a parent scope that is a function body, this
/// pointer is non-null and points to it. This is used for label processing.
Scope *FnParent;
@@ -221,6 +224,12 @@
/// isBlockScope - Return true if this scope correspond to a closure.
bool isBlockScope() const { return Flags & BlockScope; }
+ /// getBranchAttr - Return the branching attribute associated with this scope.
+ const Attr *getBranchAttr() const { return BranchAttr; }
+ Attr *getBranchAttr() { return BranchAttr; }
+
+ void setBranchAttr(Attr *Attribute) { BranchAttr = Attribute; }
+
/// getParent - Return the scope that this is nested in.
const Scope *getParent() const { return AnyParent; }
Scope *getParent() { return AnyParent; }
Index: clang/include/clang/Basic/DiagnosticSemaKinds.td
===================================================================
--- clang/include/clang/Basic/DiagnosticSemaKinds.td
+++ clang/include/clang/Basic/DiagnosticSemaKinds.td
@@ -7339,6 +7339,8 @@
"use of the %0 attribute is a C++14 extension">, InGroup<CXX14>;
def ext_cxx17_attr : Extension<
"use of the %0 attribute is a C++17 extension">, InGroup<CXX17>;
+def ext_cxx2a_attr : Extension<
+ "use of the %0 attribute is a C++2a extension">, InGroup<CXX2a>;
def warn_unused_comparison : Warning<
"%select{equality|inequality|relational|three-way}0 comparison result unused">,
@@ -8158,6 +8160,11 @@
"fallthrough annotation in unreachable code">,
InGroup<ImplicitFallthrough>, DefaultIgnore;
+def warn_no_associated_branch : Warning<
+ "attribute %0 not assiciated to any branch is ignored">, InGroup<IgnoredAttributes>;
+def warn_conflicting_attribute : Warning<
+ "%0 contradicing with previous %1 attribute">, InGroup<IgnoredAttributes>;
+
def warn_unreachable_default : Warning<
"default label in switch which covers all enumeration values">,
InGroup<CoveredSwitchDefault>, DefaultIgnore;
Index: clang/include/clang/Basic/AttrDocs.td
===================================================================
--- clang/include/clang/Basic/AttrDocs.td
+++ clang/include/clang/Basic/AttrDocs.td
@@ -1492,6 +1492,39 @@
}];
}
+def LikelihoodDocs : Documentation {
+ let Category = DocCatStmt;
+ let Heading = "likely / unlikely";
+ let Content = [{
+
+The ``likely`` or ``unlikely`` attribute is used to annotate that a statement or label is likely or unlikely to executed
+
+Here is an example:
+
+.. code-block:: c++
+
+ void g(int);
+ int f(int n) {
+ if (n > 5) [[unlikely]] { // n > 5 is considered to be arbitrarily unlikely
+ g(0);
+ return n * 2 + 1;
+ }
+
+ switch (n) {
+ case 1:
+ g(1);
+ [[fallthrough]];
+
+ [[likely]] case 2: // n == 2 is considered to be arbitrarily more
+ g(2); // likely than any other value of n
+ break;
+ }
+ return 3;
+ }
+
+ }];
+}
+
def ARMInterruptDocs : Documentation {
let Category = DocCatFunction;
let Heading = "interrupt (ARM)";
Index: clang/include/clang/Basic/Attr.td
===================================================================
--- clang/include/clang/Basic/Attr.td
+++ clang/include/clang/Basic/Attr.td
@@ -1147,6 +1147,12 @@
let Documentation = [FallthroughDocs];
}
+def Likelihood : StmtAttr {
+ let Spellings = [CXX11<"", "likely", 201803>, Clang<"likely">, CXX11<"", "unlikely", 201803>, Clang<"unlikely">];
+// let Subjects = [Stmt, LabelStmt];
+ let Documentation = [LikelihoodDocs];
+}
+
def FastCall : DeclOrTypeAttr {
let Spellings = [GCC<"fastcall">, Keyword<"__fastcall">,
Keyword<"_fastcall">];
Index: clang/include/clang/AST/Stmt.h
===================================================================
--- clang/include/clang/AST/Stmt.h
+++ clang/include/clang/AST/Stmt.h
@@ -56,6 +56,15 @@
class Token;
class VarDecl;
+// i don't konw where else to put this
+enum BranchHint : unsigned {
+ NoHint = 0,
+ Taken = 1,
+ NotTaken = 2
+ // we could add unpredictable it is directly related and the enum would fit
+ // nicely on 2 bits
+};
+
//===----------------------------------------------------------------------===//
// AST classes for statements.
//===----------------------------------------------------------------------===//
@@ -167,6 +176,9 @@
/// True if this if statement has storage for an init statement.
unsigned HasInit : 1;
+ /// holds information about likeliness of the branch being taken
+ BranchHint Hint : 2;
+
/// The location of the "if".
SourceLocation IfLoc;
};
@@ -1752,7 +1764,8 @@
/// Build an if/then/else statement.
IfStmt(const ASTContext &Ctx, SourceLocation IL, bool IsConstexpr, Stmt *Init,
- VarDecl *Var, Expr *Cond, Stmt *Then, SourceLocation EL, Stmt *Else);
+ VarDecl *Var, Expr *Cond, Stmt *Then, SourceLocation EL, Stmt *Else,
+ BranchHint Hint = NoHint);
/// Build an empty if/then/else statement.
explicit IfStmt(EmptyShell Empty, bool HasElse, bool HasVar, bool HasInit);
@@ -1762,7 +1775,8 @@
static IfStmt *Create(const ASTContext &Ctx, SourceLocation IL,
bool IsConstexpr, Stmt *Init, VarDecl *Var, Expr *Cond,
Stmt *Then, SourceLocation EL = SourceLocation(),
- Stmt *Else = nullptr);
+ Stmt *Else = nullptr,
+ BranchHint Hint = BranchHint::NoHint);
/// Create an empty IfStmt optionally with storage for an else statement,
/// condition variable and init expression.
@@ -1778,6 +1792,10 @@
/// True if this IfStmt has storage for an else statement.
bool hasElseStorage() const { return IfStmtBits.HasElse; }
+ BranchHint getBranchHint() const { return IfStmtBits.Hint; }
+
+ void setBranchHint(BranchHint Hint) { IfStmtBits.Hint = Hint; }
+
Expr *getCond() {
return reinterpret_cast<Expr *>(getTrailingObjects<Stmt *>()[condOffset()]);
}
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