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/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: