[PATCH] ms-inline-asm: Scope inline asm labels to functions

[Reid Kleckner]

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Comment at: include/clang/AST/Decl.h:312
@@ -310,1 +311,3 @@
   LabelStmt *TheStmt;
+  SmallString<16> MSAsmName;
+  bool MSAsmNameResolved;
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ehsan wrote:
> rnk wrote:
> > ehsan wrote:
> > > rnk wrote:
> > > > This will cause a memory leak for names > 16 chars. When the ASTContext is destroyed, it doesn't actually call destructors of individual AST nodes, it merely frees the memory. This should be a StringRef that points to memory from 'new (Context, 1) char[Len]', probably.
> > > Oh, I didn't know that!  What's this 'new (Contex, 1) char[Len]' trick?  I'm not familiar with it, I don't think...
> > It's an operator new overload declared in ASTContext.h. Basically, it's equivalent to 'new char[Len]', except it goes calls the 'void* operator new(size_t Bytes, ASTContext &Context, size_t Alignment)' overload.
> Hmm, who is responsible for freeing this memory?  The comments in ASTContext.h seem to suggest that I should call ASTContext::Deallocate on the pointer, but I'm not sure when I should do that if the destructor is not invoked.  Looking at other parts of the code base, it seems like nobody worries about deleting memory allocated this way...
When the ASTContext gets destroyed, it frees all memory allocated with it. It's basically a simple pool allocation scheme. The AST lives until compilation is over (i.e. forever). The clang driver even passes a -disable-free flag to prevent the -cc1 process from destroying the AST because even that is slower than just ending the process.

http://reviews.llvm.org/D4589