Author: rjmccall
Date: Tue Mar 1 00:27:40 2016
New Revision: 262308
URL: http://llvm.org/viewvc/llvm-project?rev=262308&view=rev
Log:
Better comments for ExtParameterInfo.
Modified:
cfe/trunk/include/clang/AST/Type.h
cfe/trunk/include/clang/Sema/Sema.h
Modified: cfe/trunk/include/clang/AST/Type.h
URL:
http://llvm.org/viewvc/llvm-project/cfe/trunk/include/clang/AST/Type.h?rev=262308&r1=262307&r2=262308&view=diff
==============================================================================
--- cfe/trunk/include/clang/AST/Type.h (original)
+++ cfe/trunk/include/clang/AST/Type.h Tue Mar 1 00:27:40 2016
@@ -3040,6 +3040,25 @@ public:
/// type.
class FunctionProtoType : public FunctionType, public llvm::FoldingSetNode {
public:
+ /// Interesting information about a specific parameter that can't simply
+ /// be reflected in parameter's type.
+ ///
+ /// It makes sense to model language features this way when there's some
+ /// sort of parameter-specific override (such as an attribute) that
+ /// affects how the function is called. For example, the ARC ns_consumed
+ /// attribute changes whether a parameter is passed at +0 (the default)
+ /// or +1 (ns_consumed). This must be reflected in the function type,
+ /// but isn't really a change to the parameter type.
+ ///
+ /// One serious disadvantage of modelling language features this way is
+ /// that they generally do not work with language features that attempt
+ /// to destructure types. For example, template argument deduction will
+ /// not be able to match a parameter declared as
+ /// T (*)(U)
+ /// against an argument of type
+ /// void (*)(__attribute__((ns_consumed)) id)
+ /// because the substitution of T=void, U=id into the former will
+ /// not produce the latter.
class ExtParameterInfo {
enum {
IsConsumed = 0x01,
@@ -3349,12 +3368,17 @@ public:
return exception_begin() + NumExceptions;
}
+ /// Is there any interesting extra information for any of the parameters
+ /// of this function type?
bool hasExtParameterInfos() const { return HasExtParameterInfos; }
ArrayRef<ExtParameterInfo> getExtParameterInfos() const {
assert(hasExtParameterInfos());
return ArrayRef<ExtParameterInfo>(getExtParameterInfosBuffer(),
getNumParams());
}
+ /// Return a pointer to the beginning of the array of extra parameter
+ /// information, if present, or else null if none of the parameters
+ /// carry it. This is equivalent to getExtProtoInfo().ExtParameterInfos.
const ExtParameterInfo *getExtParameterInfosOrNull() const {
if (!hasExtParameterInfos())
return nullptr;
Modified: cfe/trunk/include/clang/Sema/Sema.h
URL:
http://llvm.org/viewvc/llvm-project/cfe/trunk/include/clang/Sema/Sema.h?rev=262308&r1=262307&r2=262308&view=diff
==============================================================================
--- cfe/trunk/include/clang/Sema/Sema.h (original)
+++ cfe/trunk/include/clang/Sema/Sema.h Tue Mar 1 00:27:40 2016
@@ -6982,11 +6982,14 @@ public:
SavedPendingLocalImplicitInstantiations;
};
+ /// A helper class for building up ExtParameterInfos.
class ExtParameterInfoBuilder {
- SmallVector<FunctionProtoType::ExtParameterInfo, 4> Infos;
+ SmallVector<FunctionProtoType::ExtParameterInfo, 16> Infos;
bool HasInteresting = false;
public:
+ /// Set the ExtParameterInfo for the parameter at the given index,
+ ///
void set(unsigned index, FunctionProtoType::ExtParameterInfo info) {
assert(Infos.size() <= index);
Infos.resize(index);
@@ -6996,9 +6999,13 @@ public:
HasInteresting = (info != FunctionProtoType::ExtParameterInfo());
}
+ /// Return a pointer (suitable for setting in an ExtProtoInfo) to the
+ /// ExtParameterInfo array we've built up.
const FunctionProtoType::ExtParameterInfo *
getPointerOrNull(unsigned numParams) {
- return (HasInteresting ? Infos.data() : nullptr);
+ if (!HasInteresting) return nullptr;
+ Infos.resize(numParams);
+ return Infos.data();
}
};
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