C++1y sized deallocation: if we have a use, but not a definition, of a sized
deallocation function (and the corresponding unsized deallocation function has
been declared), emit a weak discardable definition of the function that
forwards to the corresponding unsized deallocation.
This allows a C++ standard library implementation to provide both a sized and
an unsized deallocation function, where the unsized one does not just call the
sized one, for instance by putting both in the same object file within an
archive.
git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@194055 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/include/clang/AST/Decl.h b/include/clang/AST/Decl.h
index e390a66..278ceb5 100644
--- a/include/clang/AST/Decl.h
+++ b/include/clang/AST/Decl.h
@@ -1793,6 +1793,11 @@
/// allocation function. [...]
bool isReplaceableGlobalAllocationFunction() const;
+ /// \brief Determine whether this function is a sized global deallocation
+ /// function in C++1y. If so, find and return the corresponding unsized
+ /// deallocation function.
+ FunctionDecl *getCorrespondingUnsizedGlobalDeallocationFunction() const;
+
/// Compute the language linkage.
LanguageLinkage getLanguageLinkage() const;
diff --git a/lib/AST/Decl.cpp b/lib/AST/Decl.cpp
index 5077c35..e81444e 100644
--- a/lib/AST/Decl.cpp
+++ b/lib/AST/Decl.cpp
@@ -2354,7 +2354,8 @@
// 'const std::nothrow_t &', or, in C++1y, 'std::size_t'.
QualType Ty = FPT->getArgType(1);
ASTContext &Ctx = getASTContext();
- if (Ctx.getLangOpts().SizedDeallocation && Ty == Ctx.getSizeType())
+ if (Ctx.getLangOpts().SizedDeallocation &&
+ Ctx.hasSameType(Ty, Ctx.getSizeType()))
return true;
if (!Ty->isReferenceType())
return false;
@@ -2366,6 +2367,37 @@
return RD && isNamed(RD, "nothrow_t") && isNamespaceStd(RD->getDeclContext());
}
+FunctionDecl *
+FunctionDecl::getCorrespondingUnsizedGlobalDeallocationFunction() const {
+ ASTContext &Ctx = getASTContext();
+ if (!Ctx.getLangOpts().SizedDeallocation)
+ return 0;
+
+ if (getDeclName().getNameKind() != DeclarationName::CXXOperatorName)
+ return 0;
+ if (getDeclName().getCXXOverloadedOperator() != OO_Delete &&
+ getDeclName().getCXXOverloadedOperator() != OO_Array_Delete)
+ return 0;
+ if (isa<CXXRecordDecl>(getDeclContext()))
+ return 0;
+ assert(getDeclContext()->getRedeclContext()->isTranslationUnit());
+
+ if (getNumParams() != 2 || isVariadic() ||
+ !Ctx.hasSameType(getType()->castAs<FunctionProtoType>()->getArgType(1),
+ Ctx.getSizeType()))
+ return 0;
+
+ // This is a sized deallocation function. Find the corresponding unsized
+ // deallocation function.
+ lookup_const_result R = getDeclContext()->lookup(getDeclName());
+ for (lookup_const_result::iterator RI = R.begin(), RE = R.end(); RI != RE;
+ ++RI)
+ if (FunctionDecl *FD = dyn_cast<FunctionDecl>(*RI))
+ if (FD->getNumParams() == 1 && !FD->isVariadic())
+ return FD;
+ return 0;
+}
+
LanguageLinkage FunctionDecl::getLanguageLinkage() const {
return getLanguageLinkageTemplate(*this);
}
diff --git a/lib/CodeGen/CGClass.cpp b/lib/CodeGen/CGClass.cpp
index af8cbbc..4848d75 100644
--- a/lib/CodeGen/CGClass.cpp
+++ b/lib/CodeGen/CGClass.cpp
@@ -2180,7 +2180,7 @@
return;
}
- EmitFunctionBody(Args);
+ EmitFunctionBody(Args, cast<FunctionDecl>(CurGD.getDecl())->getBody());
}
void CodeGenFunction::EmitLambdaDelegatingInvokeBody(const CXXMethodDecl *MD) {
diff --git a/lib/CodeGen/CGExpr.cpp b/lib/CodeGen/CGExpr.cpp
index 221d132..4a427d5 100644
--- a/lib/CodeGen/CGExpr.cpp
+++ b/lib/CodeGen/CGExpr.cpp
@@ -1824,8 +1824,8 @@
return LV;
}
- if (const FunctionDecl *fn = dyn_cast<FunctionDecl>(ND))
- return EmitFunctionDeclLValue(*this, E, fn);
+ if (const FunctionDecl *FD = dyn_cast<FunctionDecl>(ND))
+ return EmitFunctionDeclLValue(*this, E, FD);
llvm_unreachable("Unhandled DeclRefExpr");
}
diff --git a/lib/CodeGen/CodeGenFunction.cpp b/lib/CodeGen/CodeGenFunction.cpp
index 3ec8903..ce1b445 100644
--- a/lib/CodeGen/CodeGenFunction.cpp
+++ b/lib/CodeGen/CodeGenFunction.cpp
@@ -643,13 +643,12 @@
DI->EmitLocation(Builder, StartLoc);
}
-void CodeGenFunction::EmitFunctionBody(FunctionArgList &Args) {
- const FunctionDecl *FD = cast<FunctionDecl>(CurGD.getDecl());
- assert(FD->getBody());
- if (const CompoundStmt *S = dyn_cast<CompoundStmt>(FD->getBody()))
+void CodeGenFunction::EmitFunctionBody(FunctionArgList &Args,
+ const Stmt *Body) {
+ if (const CompoundStmt *S = dyn_cast<CompoundStmt>(Body))
EmitCompoundStmtWithoutScope(*S);
else
- EmitStmt(FD->getBody());
+ EmitStmt(Body);
}
/// Tries to mark the given function nounwind based on the
@@ -672,6 +671,17 @@
F->setDoesNotThrow();
}
+static void EmitSizedDeallocationFunction(CodeGenFunction &CGF,
+ const FunctionDecl *UnsizedDealloc) {
+ // This is a weak discardable definition of the sized deallocation function.
+ CGF.CurFn->setLinkage(llvm::Function::LinkOnceAnyLinkage);
+
+ // Call the unsized deallocation function and forward the first argument
+ // unchanged.
+ llvm::Constant *Unsized = CGF.CGM.GetAddrOfFunction(UnsizedDealloc);
+ CGF.Builder.CreateCall(Unsized, &*CGF.CurFn->arg_begin());
+}
+
void CodeGenFunction::GenerateCode(GlobalDecl GD, llvm::Function *Fn,
const CGFunctionInfo &FnInfo) {
const FunctionDecl *FD = cast<FunctionDecl>(GD.getDecl());
@@ -726,9 +736,15 @@
// Implicit copy-assignment gets the same special treatment as implicit
// copy-constructors.
emitImplicitAssignmentOperatorBody(Args);
- }
- else
- EmitFunctionBody(Args);
+ } else if (Stmt *Body = FD->getBody()) {
+ EmitFunctionBody(Args, Body);
+ } else if (FunctionDecl *UnsizedDealloc =
+ FD->getCorrespondingUnsizedGlobalDeallocationFunction()) {
+ // Global sized deallocation functions get an implicit weak definition if
+ // they don't have an explicit definition.
+ EmitSizedDeallocationFunction(*this, UnsizedDealloc);
+ } else
+ llvm_unreachable("no definition for emitted function");
// C++11 [stmt.return]p2:
// Flowing off the end of a function [...] results in undefined behavior in
diff --git a/lib/CodeGen/CodeGenFunction.h b/lib/CodeGen/CodeGenFunction.h
index b07e903..98c090f 100644
--- a/lib/CodeGen/CodeGenFunction.h
+++ b/lib/CodeGen/CodeGenFunction.h
@@ -1136,7 +1136,7 @@
void EmitConstructorBody(FunctionArgList &Args);
void EmitDestructorBody(FunctionArgList &Args);
void emitImplicitAssignmentOperatorBody(FunctionArgList &Args);
- void EmitFunctionBody(FunctionArgList &Args);
+ void EmitFunctionBody(FunctionArgList &Args, const Stmt *Body);
void EmitForwardingCallToLambda(const CXXMethodDecl *LambdaCallOperator,
CallArgList &CallArgs);
diff --git a/lib/CodeGen/CodeGenModule.cpp b/lib/CodeGen/CodeGenModule.cpp
index d0f34dd..c34f833 100644
--- a/lib/CodeGen/CodeGenModule.cpp
+++ b/lib/CodeGen/CodeGenModule.cpp
@@ -1406,6 +1406,12 @@
DeferredDeclsToEmit.push_back(DDI->second);
DeferredDecls.erase(DDI);
+ // Otherwise, if this is a sized deallocation function, emit a weak definition
+ // for it at the end of the translation unit.
+ } else if (D && cast<FunctionDecl>(D)
+ ->getCorrespondingUnsizedGlobalDeallocationFunction()) {
+ DeferredDeclsToEmit.push_back(GD);
+
// Otherwise, there are cases we have to worry about where we're
// using a declaration for which we must emit a definition but where
// we might not find a top-level definition:
diff --git a/lib/Frontend/CompilerInvocation.cpp b/lib/Frontend/CompilerInvocation.cpp
index 3da8ba7..a523acf 100644
--- a/lib/Frontend/CompilerInvocation.cpp
+++ b/lib/Frontend/CompilerInvocation.cpp
@@ -1093,6 +1093,9 @@
Opts.Trigraphs = !Opts.GNUMode;
Opts.DollarIdents = !Opts.AsmPreprocessor;
+
+ // C++1y onwards has sized global deallocation functions.
+ Opts.SizedDeallocation = Opts.CPlusPlus1y;
}
/// Attempt to parse a visibility value out of the given argument.
@@ -1310,7 +1313,7 @@
Opts.NoBuiltin = Args.hasArg(OPT_fno_builtin) || Opts.Freestanding;
Opts.NoMathBuiltin = Args.hasArg(OPT_fno_math_builtin);
Opts.AssumeSaneOperatorNew = !Args.hasArg(OPT_fno_assume_sane_operator_new);
- Opts.SizedDeallocation = Args.hasArg(OPT_fsized_deallocation);
+ Opts.SizedDeallocation |= Args.hasArg(OPT_fsized_deallocation);
Opts.HeinousExtensions = Args.hasArg(OPT_fheinous_gnu_extensions);
Opts.AccessControl = !Args.hasArg(OPT_fno_access_control);
Opts.ElideConstructors = !Args.hasArg(OPT_fno_elide_constructors);
diff --git a/test/CodeGenCXX/cxx1y-sized-deallocation.cpp b/test/CodeGenCXX/cxx1y-sized-deallocation.cpp
index 7678783..642e1e0 100644
--- a/test/CodeGenCXX/cxx1y-sized-deallocation.cpp
+++ b/test/CodeGenCXX/cxx1y-sized-deallocation.cpp
@@ -1,5 +1,6 @@
-// RUN: %clang_cc1 -std=c++1y -fsized-deallocation %s -emit-llvm -triple x86_64-linux-gnu -o - | FileCheck %s
-// RUN: %clang_cc1 -std=c++1y %s -emit-llvm -triple x86_64-linux-gnu -o - | FileCheck %s --check-prefix=CHECK-UNSIZED
+// RUN: %clang_cc1 -std=c++1y %s -emit-llvm -triple x86_64-linux-gnu -o - | FileCheck %s
+// RUN: %clang_cc1 -std=c++11 -fsized-deallocation %s -emit-llvm -triple x86_64-linux-gnu -o - | FileCheck %s
+// RUN: %clang_cc1 -std=c++11 %s -emit-llvm -triple x86_64-linux-gnu -o - | FileCheck %s --check-prefix=CHECK-UNSIZED
// CHECK-UNSIZED-NOT: _ZdlPvm
// CHECK-UNSIZED-NOT: _ZdaPvm
@@ -44,6 +45,9 @@
// CHECK: call void @_ZdlPvm(i8* %{{[^ ]*}}, i64 4)
// CHECK: call void @_ZdaPv(i8* %{{[^ ]*}})
+// CHECK-LABEL: define linkonce void @_ZdlPvm(i8*
+// CHECK: call void @_ZdlPv(i8* %0)
+
// CHECK-LABEL: define weak_odr void @_Z3delI1BEvv()
// CHECK: call void @_ZdlPvm(i8* %{{[^ ]*}}, i64 4)
// CHECK: call void @_ZdaPv(i8* %{{[^ ]*}})
@@ -54,6 +58,9 @@
// CHECK: add i64 %{{[^ ]*}}, 8
// CHECK: call void @_ZdaPvm(i8* %{{[^ ]*}}, i64 %{{[^ ]*}})
+// CHECK-LABEL: define linkonce void @_ZdaPvm(i8*
+// CHECK: call void @_ZdaPv(i8* %0)
+
// CHECK-LABEL: define weak_odr void @_Z3delI1DEvv()
// CHECK: call void @_ZdlPvm(i8* %{{[^ ]*}}, i64 8)
// CHECK: mul i64 8, %{{[^ ]*}}
diff --git a/www/cxx_status.html b/www/cxx_status.html
index 1f165b9..d2e2fc2 100644
--- a/www/cxx_status.html
+++ b/www/cxx_status.html
@@ -401,7 +401,7 @@
<h2 id="cxx14">C++1y implementation status</h2>
-<p>Clang is introducing support for the upcoming C++ language standard,
+<p>Clang implements most of the upcoming C++ language standard,
provisionally named C++1y. The following table describes which C++1y features
have been implemented in Clang and in which Clang version they became
available.</p>
@@ -476,15 +476,10 @@
<tr>
<td>C++ Sized Deallocation</td>
<td><a href="http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2013/n3778.html">N3778</a></td>
- <td class="partial" align="center">Partial <a href="#n3778">(1)</a></td>
+ <td class="svn" align="center">SVN</td>
</tr>
</table>
-<p>
-<span id="n3778">(1): Use the experimental <tt>-Xclang -fsized-deallocation</tt>
-flag to enable this feature.</span><br>
-</p>
-
</div>
</body>
</html>