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authorRichard Smith <richard-llvm@metafoo.co.uk>2013-11-05 09:12:18 +0000
committerRichard Smith <richard-llvm@metafoo.co.uk>2013-11-05 09:12:18 +0000
commitb47c36f8e113f238124fa00ae7d444d02f5b470e (patch)
tree1403473a0d2940847dbc1f4693828ec093abc1b7 /clang/lib/CodeGen/CodeGenFunction.cpp
parent2d1d3ca1cc0255faad99e2eb77cfe4b269410152 (diff)
downloadbcm5719-llvm-b47c36f8e113f238124fa00ae7d444d02f5b470e.tar.gz
bcm5719-llvm-b47c36f8e113f238124fa00ae7d444d02f5b470e.zip
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. llvm-svn: 194055
Diffstat (limited to 'clang/lib/CodeGen/CodeGenFunction.cpp')
-rw-r--r--clang/lib/CodeGen/CodeGenFunction.cpp32
1 files changed, 24 insertions, 8 deletions
diff --git a/clang/lib/CodeGen/CodeGenFunction.cpp b/clang/lib/CodeGen/CodeGenFunction.cpp
index 3ec890383c9..ce1b44559dc 100644
--- a/clang/lib/CodeGen/CodeGenFunction.cpp
+++ b/clang/lib/CodeGen/CodeGenFunction.cpp
@@ -643,13 +643,12 @@ void CodeGenFunction::StartFunction(GlobalDecl GD,
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 @@ static void TryMarkNoThrow(llvm::Function *F) {
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 @@ void CodeGenFunction::GenerateCode(GlobalDecl GD, llvm::Function *Fn,
// 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
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