Adapt to changed clang::ASTContext::getParents behavior on Clang 11 trunk

...since <https://github.com/llvm/llvm-project/commit/
d0da5d2bbe8305d06dc01a98706fd73e11e24a9f> "Change default traversal in AST
Matchers to ignore invisible nodes".  This caused failures

> [CPT] compilerplugins/clang/test/constparams.cxx
> ParmVarDecl 0x11d76c730 <compilerplugins/clang/test/constparams.cxx:15:12, col:18> col:18 used f1 'int *'
> DeclRefExpr 0x11d76c948 'int *' lvalue ParmVar 0x11d76c730 'f1' 'int *'
> ParmVarDecl 0x11d76cc80 <compilerplugins/clang/test/constparams.cxx:21:12, col:18> col:18 used f2 'int *'
> DeclRefExpr 0x11d76ce60 'int *' lvalue ParmVar 0x11d76cc80 'f2' 'int *'
> error: 'error' diagnostics expected but not seen:
>   File compilerplugins/clang/test/constparams.cxx Line 15: this parameter can be const Class1::Class1 [loplugin:constparams]
> error: 'error' diagnostics seen but not expected:
>   File compilerplugins/clang/test/constparams.cxx Line 15: no parent? [loplugin:constparams]
>   File compilerplugins/clang/test/constparams.cxx Line 21: no parent? [loplugin:constparams]
> 3 errors generated.
[...]
> [CPT] compilerplugins/clang/test/unusedenumconstants.cxx
> error: 'error' diagnostics expected but not seen:
>   File compilerplugins/clang/test/unusedenumconstants.cxx Line 30: read Bottom [loplugin:unusedenumconstants]
> error: 'error' diagnostics seen but not expected:
>   File compilerplugins/clang/test/unusedenumconstants.cxx Line 30: write Bottom [loplugin:unusedenumconstants]
> 2 errors generated.
[...]
> [CPT] compilerplugins/clang/test/unusedfields.cxx
> error: 'error' diagnostics expected but not seen:
>   File compilerplugins/clang/test/unusedfields.cxx Line 156 (directive at compilerplugins/clang/test/unusedfields.cxx:164): write m_f5 [loplugin:unusedfields]
>   File compilerplugins/clang/test/unusedfields.cxx Line 210 (directive at compilerplugins/clang/test/unusedfields.cxx:211): read m_f1 [loplugin:unusedfields]
> 2 errors generated.

For compilerplugins/clang/test/constparams.cxx at least it would have worked to
fix that locally with

> diff --git a/compilerplugins/clang/constparams.cxx b/compilerplugins/clang/constparams.cxx
> index 95c8184009d7..70f056fa5a69 100644
> --- a/compilerplugins/clang/constparams.cxx
> +++ b/compilerplugins/clang/constparams.cxx
> @@ -274,7 +274,7 @@ bool ConstParams::checkIfCanBeConst(const Stmt* stmt, const ParmVarDecl* parmVar
>              {
>                  for ( auto cxxCtorInitializer : cxxConstructorDecl->inits())
>                  {
> -                    if ( cxxCtorInitializer->getInit() == stmt)
> +                    if ( cxxCtorInitializer->getInit()->IgnoreImpCasts() == stmt)
>                      {
>                          if (cxxCtorInitializer->isAnyMemberInitializer())
>                          {

(somewhat unintuitively, given the Clang change is apparently about ignoring
more implicit nodes), but overall it appears better---at least for now---to use
a getParents variant that keeps the old traversal behavior.

For that, instead of using the clang::ASTContext::ParentMapCtx, we create our
own loplugin::Plugin::parentMapContext_.  There appear to be no uses of
ASTContext::getParent across the Clang codebase itself, outside of ASTMatcher
code, so it looks unlikely that creating our own ParentMapContext instance would
degrade performance by no longer sharing cached data between Clang's internals
and our plugin.  (And given that ASTContext::getParents is deprecated with the
note "New callers should use ParentMapContext::getParents() directly", this may
well be the correct way in the long run, anyway.)

Change-Id: I46c7912f2737e7c224fd45ab41441f69e2f10bd4
Reviewed-on: https://gerrit.libreoffice.org/c/core/+/94795
Tested-by: Jenkins
Reviewed-by: Stephan Bergmann <sbergman@redhat.com>

1 files changed, 13 insertions, 2 deletions

diff --git a/compilerplugins/clang/plugin.hxx b/compilerplugins/clang/plugin.hxx
index 361bca922035..2d43371feede 100644
--- a/compilerplugins/clang/plugin.hxx
+++ b/compilerplugins/clang/plugin.hxx
@@ -18,6 +18,8 @@
 #include <clang/Basic/SourceManager.h>
 #include <clang/Frontend/CompilerInstance.h>
 #include <clang/Lex/Preprocessor.h>
+
+#include <memory>
 #include <unordered_map>
 #include <vector>
 
@@ -26,6 +28,10 @@
 #include "compat.hxx"
 #include "pluginhandler.hxx"
 
+#if CLANG_VERSION >= 110000
+#include "clang/AST/ParentMapContext.h"
+#endif
+
 using namespace clang;
 using namespace llvm;
 
@@ -78,8 +84,11 @@ protected:
      Returns the parent of the given AST node. Clang's internal AST representation doesn't provide this information,
      it can only provide children, but getting the parent is often useful for inspecting a part of the AST.
     */
+    compat::DynTypedNodeList getParents(Decl const & decl);
+    compat::DynTypedNodeList getParents(Stmt const & stmt);
     const Stmt* getParentStmt( const Stmt* stmt );
     Stmt* getParentStmt( Stmt* stmt );
+    const Decl* getFunctionDeclContext(const Stmt* stmt);
     const FunctionDecl* getParentFunctionDecl( const Stmt* stmt );
 
     /**
@@ -112,6 +121,10 @@ private:
 
     enum { isRewriter = false };
     const char* name;
+
+#if CLANG_VERSION >= 110000
+    std::unique_ptr<ParentMapContext> parentMapContext_;
+#endif
 };
 
 template<typename Derived>
@@ -309,8 +322,6 @@ bool hasExternalLinkage(VarDecl const * decl);
 bool isSmartPointerType(const clang::Type*);
 bool isSmartPointerType(const Expr*);
 
-const Decl* getFunctionDeclContext(ASTContext& context, const Stmt* stmt);
-
 } // namespace
 
 #endif // COMPILEPLUGIN_H