rsmith updated this revision to Diff 215678.
rsmith marked 2 inline comments as done.
rsmith added a comment.
- Review feedback: use _AddressOfReturnAddress with MSVC, and simplify
Repository:
rC Clang
CHANGES SINCE LAST ACTION
https://reviews.llvm.org/D66361/new/
https://reviews.llvm.org/D66361
Files:
include/clang/Basic/DiagnosticSemaKinds.td
include/clang/Basic/Stack.h
include/clang/Sema/Sema.h
lib/Basic/CMakeLists.txt
lib/Basic/Stack.cpp
lib/Frontend/CompilerInstance.cpp
lib/Sema/Sema.cpp
lib/Sema/SemaExpr.cpp
lib/Sema/SemaInit.cpp
lib/Sema/SemaLookup.cpp
lib/Sema/SemaTemplate.cpp
lib/Sema/SemaTemplateDeduction.cpp
lib/Sema/SemaTemplateInstantiate.cpp
lib/Sema/SemaTemplateInstantiateDecl.cpp
lib/Sema/SemaType.cpp
test/SemaTemplate/stack-exhaustion.cpp
tools/driver/driver.cpp
Index: tools/driver/driver.cpp
===================================================================
--- tools/driver/driver.cpp
+++ tools/driver/driver.cpp
@@ -13,6 +13,7 @@
#include "clang/Driver/Driver.h"
#include "clang/Basic/DiagnosticOptions.h"
+#include "clang/Basic/Stack.h"
#include "clang/Driver/Compilation.h"
#include "clang/Driver/DriverDiagnostic.h"
#include "clang/Driver/Options.h"
@@ -319,6 +320,7 @@
}
int main(int argc_, const char **argv_) {
+ noteBottomOfStack();
llvm::InitLLVM X(argc_, argv_);
SmallVector<const char *, 256> argv(argv_, argv_ + argc_);
Index: test/SemaTemplate/stack-exhaustion.cpp
===================================================================
--- /dev/null
+++ test/SemaTemplate/stack-exhaustion.cpp
@@ -0,0 +1,16 @@
+// RUN: %clang_cc1 -verify %s
+// expected-warning@* 0-1{{stack nearly exhausted}}
+// expected-note@* 0+{{}}
+
+template<int N> struct X : X<N-1> {};
+template<> struct X<0> {};
+X<1000> x;
+
+template<typename ...T> struct tuple {};
+template<typename ...T> auto f(tuple<T...> t) -> decltype(f(tuple<T...>(t))) {} // expected-error {{exceeded maximum depth}}
+void g() { f(tuple<int, int>()); }
+
+int f(X<0>);
+template<int N> auto f(X<N>) -> f(X<N-1>());
+
+int k = f(X<1000>());
Index: lib/Sema/SemaType.cpp
===================================================================
--- lib/Sema/SemaType.cpp
+++ lib/Sema/SemaType.cpp
@@ -7715,7 +7715,9 @@
auto *Def = Var->getDefinition();
if (!Def) {
SourceLocation PointOfInstantiation = E->getExprLoc();
- InstantiateVariableDefinition(PointOfInstantiation, Var);
+ runWithSufficientStackSpace(PointOfInstantiation, [&] {
+ InstantiateVariableDefinition(PointOfInstantiation, Var);
+ });
Def = Var->getDefinition();
// If we don't already have a point of instantiation, and we managed
@@ -8053,9 +8055,11 @@
} else if (auto *ClassTemplateSpec =
dyn_cast<ClassTemplateSpecializationDecl>(RD)) {
if (ClassTemplateSpec->getSpecializationKind() == TSK_Undeclared) {
- Diagnosed = InstantiateClassTemplateSpecialization(
- Loc, ClassTemplateSpec, TSK_ImplicitInstantiation,
- /*Complain=*/Diagnoser);
+ runWithSufficientStackSpace(Loc, [&] {
+ Diagnosed = InstantiateClassTemplateSpecialization(
+ Loc, ClassTemplateSpec, TSK_ImplicitInstantiation,
+ /*Complain=*/Diagnoser);
+ });
Instantiated = true;
}
} else {
@@ -8066,10 +8070,12 @@
// This record was instantiated from a class within a template.
if (MSI->getTemplateSpecializationKind() !=
TSK_ExplicitSpecialization) {
- Diagnosed = InstantiateClass(Loc, RD, Pattern,
- getTemplateInstantiationArgs(RD),
- TSK_ImplicitInstantiation,
- /*Complain=*/Diagnoser);
+ runWithSufficientStackSpace(Loc, [&] {
+ Diagnosed = InstantiateClass(Loc, RD, Pattern,
+ getTemplateInstantiationArgs(RD),
+ TSK_ImplicitInstantiation,
+ /*Complain=*/Diagnoser);
+ });
Instantiated = true;
}
}
Index: lib/Sema/SemaTemplateInstantiateDecl.cpp
===================================================================
--- lib/Sema/SemaTemplateInstantiateDecl.cpp
+++ lib/Sema/SemaTemplateInstantiateDecl.cpp
@@ -3415,7 +3415,11 @@
if (D->isInvalidDecl())
return nullptr;
- return Instantiator.Visit(D);
+ Decl *SubstD;
+ runWithSufficientStackSpace(D->getLocation(), [&] {
+ SubstD = Instantiator.Visit(D);
+ });
+ return SubstD;
}
/// Instantiates a nested template parameter list in the current
Index: lib/Sema/SemaTemplateInstantiate.cpp
===================================================================
--- lib/Sema/SemaTemplateInstantiate.cpp
+++ lib/Sema/SemaTemplateInstantiate.cpp
@@ -19,6 +19,7 @@
#include "clang/AST/Expr.h"
#include "clang/AST/PrettyDeclStackTrace.h"
#include "clang/Basic/LangOptions.h"
+#include "clang/Basic/Stack.h"
#include "clang/Sema/DeclSpec.h"
#include "clang/Sema/Initialization.h"
#include "clang/Sema/Lookup.h"
@@ -365,6 +366,11 @@
if (!Ctx.isInstantiationRecord())
++NonInstantiationEntries;
+
+ // Check to see if we're low on stack space. We can't do anything about this
+ // from here, but we can at least warn the user.
+ if (isStackNearlyExhausted())
+ warnStackExhausted(Ctx.PointOfInstantiation);
}
void Sema::popCodeSynthesisContext() {
Index: lib/Sema/SemaTemplateDeduction.cpp
===================================================================
--- lib/Sema/SemaTemplateDeduction.cpp
+++ lib/Sema/SemaTemplateDeduction.cpp
@@ -4632,8 +4632,11 @@
// We might need to deduce the return type by instantiating the definition
// of the operator() function.
- if (CallOp->getReturnType()->isUndeducedType())
- InstantiateFunctionDefinition(Loc, CallOp);
+ if (CallOp->getReturnType()->isUndeducedType()) {
+ runWithSufficientStackSpace(Loc, [&] {
+ InstantiateFunctionDefinition(Loc, CallOp);
+ });
+ }
}
if (CallOp->isInvalidDecl())
@@ -4654,8 +4657,11 @@
return false;
}
- if (FD->getTemplateInstantiationPattern())
- InstantiateFunctionDefinition(Loc, FD);
+ if (FD->getTemplateInstantiationPattern()) {
+ runWithSufficientStackSpace(Loc, [&] {
+ InstantiateFunctionDefinition(Loc, FD);
+ });
+ }
bool StillUndeduced = FD->getReturnType()->isUndeducedType();
if (StillUndeduced && Diagnose && !FD->isInvalidDecl()) {
Index: lib/Sema/SemaTemplate.cpp
===================================================================
--- lib/Sema/SemaTemplate.cpp
+++ lib/Sema/SemaTemplate.cpp
@@ -20,6 +20,7 @@
#include "clang/Basic/Builtins.h"
#include "clang/Basic/LangOptions.h"
#include "clang/Basic/PartialDiagnostic.h"
+#include "clang/Basic/Stack.h"
#include "clang/Basic/TargetInfo.h"
#include "clang/Sema/DeclSpec.h"
#include "clang/Sema/Lookup.h"
Index: lib/Sema/SemaLookup.cpp
===================================================================
--- lib/Sema/SemaLookup.cpp
+++ lib/Sema/SemaLookup.cpp
@@ -3016,8 +3016,11 @@
SpecialMemberCache.InsertNode(Result, InsertPoint);
if (SM == CXXDestructor) {
- if (RD->needsImplicitDestructor())
- DeclareImplicitDestructor(RD);
+ if (RD->needsImplicitDestructor()) {
+ runWithSufficientStackSpace(RD->getLocation(), [&] {
+ DeclareImplicitDestructor(RD);
+ });
+ }
CXXDestructorDecl *DD = RD->getDestructor();
assert(DD && "record without a destructor");
Result->setMethod(DD);
@@ -3040,21 +3043,36 @@
if (SM == CXXDefaultConstructor) {
Name = Context.DeclarationNames.getCXXConstructorName(CanTy);
NumArgs = 0;
- if (RD->needsImplicitDefaultConstructor())
- DeclareImplicitDefaultConstructor(RD);
+ if (RD->needsImplicitDefaultConstructor()) {
+ runWithSufficientStackSpace(RD->getLocation(), [&] {
+ DeclareImplicitDefaultConstructor(RD);
+ });
+ }
} else {
if (SM == CXXCopyConstructor || SM == CXXMoveConstructor) {
Name = Context.DeclarationNames.getCXXConstructorName(CanTy);
- if (RD->needsImplicitCopyConstructor())
- DeclareImplicitCopyConstructor(RD);
- if (getLangOpts().CPlusPlus11 && RD->needsImplicitMoveConstructor())
- DeclareImplicitMoveConstructor(RD);
+ if (RD->needsImplicitCopyConstructor()) {
+ runWithSufficientStackSpace(RD->getLocation(), [&] {
+ DeclareImplicitCopyConstructor(RD);
+ });
+ }
+ if (getLangOpts().CPlusPlus11 && RD->needsImplicitMoveConstructor()) {
+ runWithSufficientStackSpace(RD->getLocation(), [&] {
+ DeclareImplicitMoveConstructor(RD);
+ });
+ }
} else {
Name = Context.DeclarationNames.getCXXOperatorName(OO_Equal);
- if (RD->needsImplicitCopyAssignment())
- DeclareImplicitCopyAssignment(RD);
- if (getLangOpts().CPlusPlus11 && RD->needsImplicitMoveAssignment())
- DeclareImplicitMoveAssignment(RD);
+ if (RD->needsImplicitCopyAssignment()) {
+ runWithSufficientStackSpace(RD->getLocation(), [&] {
+ DeclareImplicitCopyAssignment(RD);
+ });
+ }
+ if (getLangOpts().CPlusPlus11 && RD->needsImplicitMoveAssignment()) {
+ runWithSufficientStackSpace(RD->getLocation(), [&] {
+ DeclareImplicitMoveAssignment(RD);
+ });
+ }
}
if (ConstArg)
@@ -3211,12 +3229,14 @@
DeclContext::lookup_result Sema::LookupConstructors(CXXRecordDecl *Class) {
// If the implicit constructors have not yet been declared, do so now.
if (CanDeclareSpecialMemberFunction(Class)) {
- if (Class->needsImplicitDefaultConstructor())
- DeclareImplicitDefaultConstructor(Class);
- if (Class->needsImplicitCopyConstructor())
- DeclareImplicitCopyConstructor(Class);
- if (getLangOpts().CPlusPlus11 && Class->needsImplicitMoveConstructor())
- DeclareImplicitMoveConstructor(Class);
+ runWithSufficientStackSpace(Class->getLocation(), [&] {
+ if (Class->needsImplicitDefaultConstructor())
+ DeclareImplicitDefaultConstructor(Class);
+ if (Class->needsImplicitCopyConstructor())
+ DeclareImplicitCopyConstructor(Class);
+ if (getLangOpts().CPlusPlus11 && Class->needsImplicitMoveConstructor())
+ DeclareImplicitMoveConstructor(Class);
+ });
}
CanQualType T = Context.getCanonicalType(Context.getTypeDeclType(Class));
Index: lib/Sema/SemaInit.cpp
===================================================================
--- lib/Sema/SemaInit.cpp
+++ lib/Sema/SemaInit.cpp
@@ -6242,8 +6242,11 @@
// the definition for completely trivial constructors.
assert(Constructor->getParent() && "No parent class for constructor.");
if (Constructor->isDefaulted() && Constructor->isDefaultConstructor() &&
- Constructor->isTrivial() && !Constructor->isUsed(false))
- S.DefineImplicitDefaultConstructor(Loc, Constructor);
+ Constructor->isTrivial() && !Constructor->isUsed(false)) {
+ S.runWithSufficientStackSpace(Loc, [&] {
+ S.DefineImplicitDefaultConstructor(Loc, Constructor);
+ });
+ }
}
ExprResult CurInit((Expr *)nullptr);
Index: lib/Sema/SemaExpr.cpp
===================================================================
--- lib/Sema/SemaExpr.cpp
+++ lib/Sema/SemaExpr.cpp
@@ -4832,8 +4832,10 @@
// default argument expression appears.
ContextRAII SavedContext(*this, FD);
LocalInstantiationScope Local(*this);
- Result = SubstInitializer(UninstExpr, MutiLevelArgList,
- /*DirectInit*/false);
+ runWithSufficientStackSpace(CallLoc, [&] {
+ Result = SubstInitializer(UninstExpr, MutiLevelArgList,
+ /*DirectInit*/false);
+ });
}
if (Result.isInvalid())
return true;
@@ -15065,6 +15067,17 @@
if (IsRecursiveCall && OdrUse == OdrUseContext::Used)
OdrUse = OdrUseContext::FormallyOdrUsed;
+ // Trivial default constructors and destructors are never actually used.
+ // FIXME: What about other special members?
+ if (Func->isTrivial() && !Func->hasAttr<DLLExportAttr>() &&
+ OdrUse == OdrUseContext::Used) {
+ if (auto *Constructor = dyn_cast<CXXConstructorDecl>(Func))
+ if (Constructor->isDefaultConstructor())
+ OdrUse = OdrUseContext::FormallyOdrUsed;
+ if (isa<CXXDestructorDecl>(Func))
+ OdrUse = OdrUseContext::FormallyOdrUsed;
+ }
+
// C++20 [expr.const]p12:
// A function [...] is needed for constant evaluation if it is [...] a
// constexpr function that is named by an expression that is potentially
@@ -15125,98 +15138,101 @@
// If we need a definition, try to create one.
if (NeedDefinition && !Func->getBody()) {
- if (CXXConstructorDecl *Constructor = dyn_cast<CXXConstructorDecl>(Func)) {
- Constructor = cast<CXXConstructorDecl>(Constructor->getFirstDecl());
- if (Constructor->isDefaulted() && !Constructor->isDeleted()) {
- if (Constructor->isDefaultConstructor()) {
- if (Constructor->isTrivial() &&
- !Constructor->hasAttr<DLLExportAttr>())
+ runWithSufficientStackSpace(Loc, [&] {
+ if (CXXConstructorDecl *Constructor =
+ dyn_cast<CXXConstructorDecl>(Func)) {
+ Constructor = cast<CXXConstructorDecl>(Constructor->getFirstDecl());
+ if (Constructor->isDefaulted() && !Constructor->isDeleted()) {
+ if (Constructor->isDefaultConstructor()) {
+ if (Constructor->isTrivial() &&
+ !Constructor->hasAttr<DLLExportAttr>())
+ return;
+ DefineImplicitDefaultConstructor(Loc, Constructor);
+ } else if (Constructor->isCopyConstructor()) {
+ DefineImplicitCopyConstructor(Loc, Constructor);
+ } else if (Constructor->isMoveConstructor()) {
+ DefineImplicitMoveConstructor(Loc, Constructor);
+ }
+ } else if (Constructor->getInheritedConstructor()) {
+ DefineInheritingConstructor(Loc, Constructor);
+ }
+ } else if (CXXDestructorDecl *Destructor =
+ dyn_cast<CXXDestructorDecl>(Func)) {
+ Destructor = cast<CXXDestructorDecl>(Destructor->getFirstDecl());
+ if (Destructor->isDefaulted() && !Destructor->isDeleted()) {
+ if (Destructor->isTrivial() && !Destructor->hasAttr<DLLExportAttr>())
return;
- DefineImplicitDefaultConstructor(Loc, Constructor);
- } else if (Constructor->isCopyConstructor()) {
- DefineImplicitCopyConstructor(Loc, Constructor);
- } else if (Constructor->isMoveConstructor()) {
- DefineImplicitMoveConstructor(Loc, Constructor);
+ DefineImplicitDestructor(Loc, Destructor);
}
- } else if (Constructor->getInheritedConstructor()) {
- DefineInheritingConstructor(Loc, Constructor);
+ if (Destructor->isVirtual() && getLangOpts().AppleKext)
+ MarkVTableUsed(Loc, Destructor->getParent());
+ } else if (CXXMethodDecl *MethodDecl = dyn_cast<CXXMethodDecl>(Func)) {
+ if (MethodDecl->isOverloadedOperator() &&
+ MethodDecl->getOverloadedOperator() == OO_Equal) {
+ MethodDecl = cast<CXXMethodDecl>(MethodDecl->getFirstDecl());
+ if (MethodDecl->isDefaulted() && !MethodDecl->isDeleted()) {
+ if (MethodDecl->isCopyAssignmentOperator())
+ DefineImplicitCopyAssignment(Loc, MethodDecl);
+ else if (MethodDecl->isMoveAssignmentOperator())
+ DefineImplicitMoveAssignment(Loc, MethodDecl);
+ }
+ } else if (isa<CXXConversionDecl>(MethodDecl) &&
+ MethodDecl->getParent()->isLambda()) {
+ CXXConversionDecl *Conversion =
+ cast<CXXConversionDecl>(MethodDecl->getFirstDecl());
+ if (Conversion->isLambdaToBlockPointerConversion())
+ DefineImplicitLambdaToBlockPointerConversion(Loc, Conversion);
+ else
+ DefineImplicitLambdaToFunctionPointerConversion(Loc, Conversion);
+ } else if (MethodDecl->isVirtual() && getLangOpts().AppleKext)
+ MarkVTableUsed(Loc, MethodDecl->getParent());
}
- } else if (CXXDestructorDecl *Destructor =
- dyn_cast<CXXDestructorDecl>(Func)) {
- Destructor = cast<CXXDestructorDecl>(Destructor->getFirstDecl());
- if (Destructor->isDefaulted() && !Destructor->isDeleted()) {
- if (Destructor->isTrivial() && !Destructor->hasAttr<DLLExportAttr>())
- return;
- DefineImplicitDestructor(Loc, Destructor);
- }
- if (Destructor->isVirtual() && getLangOpts().AppleKext)
- MarkVTableUsed(Loc, Destructor->getParent());
- } else if (CXXMethodDecl *MethodDecl = dyn_cast<CXXMethodDecl>(Func)) {
- if (MethodDecl->isOverloadedOperator() &&
- MethodDecl->getOverloadedOperator() == OO_Equal) {
- MethodDecl = cast<CXXMethodDecl>(MethodDecl->getFirstDecl());
- if (MethodDecl->isDefaulted() && !MethodDecl->isDeleted()) {
- if (MethodDecl->isCopyAssignmentOperator())
- DefineImplicitCopyAssignment(Loc, MethodDecl);
- else if (MethodDecl->isMoveAssignmentOperator())
- DefineImplicitMoveAssignment(Loc, MethodDecl);
- }
- } else if (isa<CXXConversionDecl>(MethodDecl) &&
- MethodDecl->getParent()->isLambda()) {
- CXXConversionDecl *Conversion =
- cast<CXXConversionDecl>(MethodDecl->getFirstDecl());
- if (Conversion->isLambdaToBlockPointerConversion())
- DefineImplicitLambdaToBlockPointerConversion(Loc, Conversion);
- else
- DefineImplicitLambdaToFunctionPointerConversion(Loc, Conversion);
- } else if (MethodDecl->isVirtual() && getLangOpts().AppleKext)
- MarkVTableUsed(Loc, MethodDecl->getParent());
- }
- // Implicit instantiation of function templates and member functions of
- // class templates.
- if (Func->isImplicitlyInstantiable()) {
- TemplateSpecializationKind TSK =
- Func->getTemplateSpecializationKindForInstantiation();
- SourceLocation PointOfInstantiation = Func->getPointOfInstantiation();
- bool FirstInstantiation = PointOfInstantiation.isInvalid();
- if (FirstInstantiation) {
- PointOfInstantiation = Loc;
- Func->setTemplateSpecializationKind(TSK, PointOfInstantiation);
- } else if (TSK != TSK_ImplicitInstantiation) {
- // Use the point of use as the point of instantiation, instead of the
- // point of explicit instantiation (which we track as the actual point
- // of instantiation). This gives better backtraces in diagnostics.
- PointOfInstantiation = Loc;
- }
+ // Implicit instantiation of function templates and member functions of
+ // class templates.
+ if (Func->isImplicitlyInstantiable()) {
+ TemplateSpecializationKind TSK =
+ Func->getTemplateSpecializationKindForInstantiation();
+ SourceLocation PointOfInstantiation = Func->getPointOfInstantiation();
+ bool FirstInstantiation = PointOfInstantiation.isInvalid();
+ if (FirstInstantiation) {
+ PointOfInstantiation = Loc;
+ Func->setTemplateSpecializationKind(TSK, PointOfInstantiation);
+ } else if (TSK != TSK_ImplicitInstantiation) {
+ // Use the point of use as the point of instantiation, instead of the
+ // point of explicit instantiation (which we track as the actual point
+ // of instantiation). This gives better backtraces in diagnostics.
+ PointOfInstantiation = Loc;
+ }
- if (FirstInstantiation || TSK != TSK_ImplicitInstantiation ||
- Func->isConstexpr()) {
- if (isa<CXXRecordDecl>(Func->getDeclContext()) &&
- cast<CXXRecordDecl>(Func->getDeclContext())->isLocalClass() &&
- CodeSynthesisContexts.size())
- PendingLocalImplicitInstantiations.push_back(
- std::make_pair(Func, PointOfInstantiation));
- else if (Func->isConstexpr())
- // Do not defer instantiations of constexpr functions, to avoid the
- // expression evaluator needing to call back into Sema if it sees a
- // call to such a function.
- InstantiateFunctionDefinition(PointOfInstantiation, Func);
- else {
- Func->setInstantiationIsPending(true);
- PendingInstantiations.push_back(
- std::make_pair(Func, PointOfInstantiation));
- // Notify the consumer that a function was implicitly instantiated.
- Consumer.HandleCXXImplicitFunctionInstantiation(Func);
+ if (FirstInstantiation || TSK != TSK_ImplicitInstantiation ||
+ Func->isConstexpr()) {
+ if (isa<CXXRecordDecl>(Func->getDeclContext()) &&
+ cast<CXXRecordDecl>(Func->getDeclContext())->isLocalClass() &&
+ CodeSynthesisContexts.size())
+ PendingLocalImplicitInstantiations.push_back(
+ std::make_pair(Func, PointOfInstantiation));
+ else if (Func->isConstexpr())
+ // Do not defer instantiations of constexpr functions, to avoid the
+ // expression evaluator needing to call back into Sema if it sees a
+ // call to such a function.
+ InstantiateFunctionDefinition(PointOfInstantiation, Func);
+ else {
+ Func->setInstantiationIsPending(true);
+ PendingInstantiations.push_back(
+ std::make_pair(Func, PointOfInstantiation));
+ // Notify the consumer that a function was implicitly instantiated.
+ Consumer.HandleCXXImplicitFunctionInstantiation(Func);
+ }
+ }
+ } else {
+ // Walk redefinitions, as some of them may be instantiable.
+ for (auto i : Func->redecls()) {
+ if (!i->isUsed(false) && i->isImplicitlyInstantiable())
+ MarkFunctionReferenced(Loc, i, MightBeOdrUse);
}
}
- } else {
- // Walk redefinitions, as some of them may be instantiable.
- for (auto i : Func->redecls()) {
- if (!i->isUsed(false) && i->isImplicitlyInstantiable())
- MarkFunctionReferenced(Loc, i, MightBeOdrUse);
- }
- }
+ });
}
// If this is the first "real" use, act on that.
@@ -16378,7 +16394,9 @@
if (UsableInConstantExpr) {
// Do not defer instantiations of variables that could be used in a
// constant expression.
- SemaRef.InstantiateVariableDefinition(PointOfInstantiation, Var);
+ SemaRef.runWithSufficientStackSpace(PointOfInstantiation, [&] {
+ SemaRef.InstantiateVariableDefinition(PointOfInstantiation, Var);
+ });
} else if (FirstInstantiation ||
isa<VarTemplateSpecializationDecl>(Var)) {
// FIXME: For a specialization of a variable template, we don't
Index: lib/Sema/Sema.cpp
===================================================================
--- lib/Sema/Sema.cpp
+++ lib/Sema/Sema.cpp
@@ -22,6 +22,7 @@
#include "clang/AST/StmtCXX.h"
#include "clang/Basic/DiagnosticOptions.h"
#include "clang/Basic/PartialDiagnostic.h"
+#include "clang/Basic/Stack.h"
#include "clang/Basic/TargetInfo.h"
#include "clang/Lex/HeaderSearch.h"
#include "clang/Lex/Preprocessor.h"
@@ -386,6 +387,19 @@
assert(DelayedTypos.empty() && "Uncorrected typos!");
}
+void Sema::warnStackExhausted(SourceLocation Loc) {
+ // Only warn about this once.
+ if (!WarnedStackExhausted) {
+ Diag(Loc, diag::warn_stack_exhausted);
+ WarnedStackExhausted = true;
+ }
+}
+
+void Sema::runWithSufficientStackSpace(SourceLocation Loc,
+ llvm::function_ref<void()> Fn) {
+ clang::runWithSufficientStackSpace([&] { warnStackExhausted(Loc); }, Fn);
+}
+
/// makeUnavailableInSystemHeader - There is an error in the current
/// context. If we're still in a system header, and we can plausibly
/// make the relevant declaration unavailable instead of erroring, do
Index: lib/Frontend/CompilerInstance.cpp
===================================================================
--- lib/Frontend/CompilerInstance.cpp
+++ lib/Frontend/CompilerInstance.cpp
@@ -886,6 +886,11 @@
assert(!getFrontendOpts().ShowHelp && "Client must handle '-help'!");
assert(!getFrontendOpts().ShowVersion && "Client must handle '-version'!");
+ // Mark this point as the bottom of the stack if we don't have somewhere
+ // better. We generally expect frontend actions to be invoked with (nearly)
+ // DesiredStackSpace available.
+ noteBottomOfStack();
+
// FIXME: Take this as an argument, once all the APIs we used have moved to
// taking it as an input instead of hard-coding llvm::errs.
raw_ostream &OS = llvm::errs();
Index: lib/Basic/Stack.cpp
===================================================================
--- /dev/null
+++ lib/Basic/Stack.cpp
@@ -0,0 +1,71 @@
+//===--- Stack.h - Utilities for dealing with stack space -------*- 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
+//
+//===----------------------------------------------------------------------===//
+///
+/// \file
+/// Defines utilities for dealing with stack allocation and stack space.
+///
+//===----------------------------------------------------------------------===//
+
+#include "clang/Basic/Stack.h"
+#include "llvm/ADT/Optional.h"
+#include "llvm/Support/CrashRecoveryContext.h"
+
+static LLVM_THREAD_LOCAL void *BottomOfStack = nullptr;
+
+static void *getStackPointer() {
+#if __GNUC__ || __has_builtin(__builtin_frame_address)
+ return __builtin_frame_address(0);
+#elif defined(_MSC_VER)
+ return _AddressOfReturnAddress();
+#else
+ char CharOnStack = 0;
+ // The volatile store here is intended to escape the local variable, to
+ // prevent the compiler from optimizing CharOnStack into anything other
+ // than a char on the stack.
+ //
+ // Tested on: MSVC 2015 - 2019, GCC 4.9 - 9, Clang 3.2 - 9, ICC 13 - 19.
+ char *volatile Ptr = &CharOnStack;
+ return Ptr;
+#endif
+}
+
+void clang::noteBottomOfStack() {
+ if (!BottomOfStack)
+ BottomOfStack = getStackPointer();
+}
+
+bool clang::isStackNearlyExhausted() {
+ // We consider 256 KiB to be sufficient for any code that runs between checks
+ // for stack size.
+ constexpr size_t SufficientStack = 256 << 10;
+
+ // If we don't know where the bottom of the stack is, hope for the best.
+ if (!BottomOfStack)
+ return false;
+
+ intptr_t StackDiff = (intptr_t)getStackPointer() - (intptr_t)BottomOfStack;
+ size_t StackUsage = (size_t)std::abs(StackDiff);
+
+ // If the stack pointer has a surprising value, we do not understand this
+ // stack usage scheme. (Perhaps the target allocates new stack regions on
+ // demand for us.) Don't try to guess what's going on.
+ if (StackUsage > DesiredStackSize)
+ return false;
+
+ return StackUsage >= DesiredStackSize - SufficientStack;
+}
+
+void clang::runWithSufficientStackSpaceSlow(llvm::function_ref<void()> Diag,
+ llvm::function_ref<void()> Fn) {
+ llvm::CrashRecoveryContext CRC;
+ CRC.RunSafelyOnThread([&] {
+ noteBottomOfStack();
+ Diag();
+ Fn();
+ }, DesiredStackSize);
+}
Index: lib/Basic/CMakeLists.txt
===================================================================
--- lib/Basic/CMakeLists.txt
+++ lib/Basic/CMakeLists.txt
@@ -60,6 +60,7 @@
Sanitizers.cpp
SourceLocation.cpp
SourceManager.cpp
+ Stack.cpp
TargetInfo.cpp
Targets.cpp
Targets/AArch64.cpp
Index: include/clang/Sema/Sema.h
===================================================================
--- include/clang/Sema/Sema.h
+++ include/clang/Sema/Sema.h
@@ -1272,6 +1272,8 @@
void addImplicitTypedef(StringRef Name, QualType T);
+ bool WarnedStackExhausted = false;
+
public:
Sema(Preprocessor &pp, ASTContext &ctxt, ASTConsumer &consumer,
TranslationUnitKind TUKind = TU_Complete,
@@ -1303,6 +1305,16 @@
void PrintStats() const;
+ /// Warn that the stack is nearly exhausted.
+ void warnStackExhausted(SourceLocation Loc);
+
+ /// Run some code with "sufficient" stack space. (Currently, at least 256K is
+ /// guaranteed). Produces a warning if we're low on stack space and allocates
+ /// more in that case. Use this in code that may recurse deeply (for example,
+ /// in template instantiation) to avoid stack overflow.
+ void runWithSufficientStackSpace(SourceLocation Loc,
+ llvm::function_ref<void()> Fn);
+
/// Helper class that creates diagnostics with optional
/// template instantiation stacks.
///
Index: include/clang/Basic/Stack.h
===================================================================
--- include/clang/Basic/Stack.h
+++ include/clang/Basic/Stack.h
@@ -16,11 +16,41 @@
#include <cstddef>
+#include "llvm/ADT/STLExtras.h"
+#include "llvm/Support/Compiler.h"
+
namespace clang {
/// The amount of stack space that Clang would like to be provided with.
/// If less than this much is available, we may be unable to reach our
/// template instantiation depth limit and other similar limits.
constexpr size_t DesiredStackSize = 8 << 20;
+
+ /// Call this once on each thread, as soon after starting the thread as
+ /// feasible, to note the approximate address of the bottom of the stack.
+ void noteBottomOfStack();
+
+ /// Determine whether the stack is nearly exhausted.
+ bool isStackNearlyExhausted();
+
+ void runWithSufficientStackSpaceSlow(llvm::function_ref<void()> Diag,
+ llvm::function_ref<void()> Fn);
+
+ /// Run a given function on a stack with "sufficient" space. If stack space
+ /// is insufficient, calls Diag to emit a diagnostic before calling Fn.
+ inline void runWithSufficientStackSpace(llvm::function_ref<void()> Diag,
+ llvm::function_ref<void()> Fn) {
+#ifdef LLVM_ENABLE_THREADS
+ if (LLVM_UNLIKELY(isStackNearlyExhausted())) {
+ runWithSufficientStackSpaceSlow(Diag, Fn);
+ } else {
+ Fn();
+ }
+#else
+ if (LLVM_UNLIKELY(isStackNearlyExhausted()))
+ Diag();
+ Fn();
+#endif
+ }
} // end namespace clang
#endif // LLVM_CLANG_BASIC_STACK_H
Index: include/clang/Basic/DiagnosticSemaKinds.td
===================================================================
--- include/clang/Basic/DiagnosticSemaKinds.td
+++ include/clang/Basic/DiagnosticSemaKinds.td
@@ -11,8 +11,12 @@
//===----------------------------------------------------------------------===//
let Component = "Sema" in {
-let CategoryName = "Semantic Issue" in {
+def warn_stack_exhausted : Warning<
+ "stack nearly exhausted; compilation time may suffer, and "
+ "crashes due to stack overflow are likely">,
+ InGroup<DiagGroup<"stack-exhausted">>, NoSFINAE;
+let CategoryName = "Semantic Issue" in {
def note_previous_decl : Note<"%0 declared here">;
def note_entity_declared_at : Note<"%0 declared here">;
def note_callee_decl : Note<"%0 declared here">;
_______________________________________________
cfe-commits mailing list
cfe-commits@lists.llvm.org
https://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits
