Undefine noinline macro if conflicts with AST dump

In kernel sourcecode there is a definition of a macro:
```
```

This seems harmless, but when clang-extract decides to dump the AST of
a Decl, this conflicts with its attr:
```
__attribute__((noinline))
```
which results in the resulting code being broken. Hence, undefine this
macro for the AST dump and define it later.

Signed-off-by: Giuliano Belinassi <[email protected]>

libcextract/PrettyPrint.cpp

@@ -62,6 +62,18 @@ bool PrettyPrint::Is_Range_Valid(const SourceRange &range)
   return Is_Before(begin, end) && (begin != end);
 }
 
+bool Has_NoInline_Attr(Decl *decl)
+{
+  const AttrVec &attrs = decl->getAttrs();
+  for (const Attr *attr : attrs) {
+    if (attr->getKind() == attr::NoInline) {
+      return true;
+    }
+  }
+
+  return false;
+}
+
 void PrettyPrint::Print_Decl_Raw(Decl *decl)
 {
   SourceRange decl_range = decl->getSourceRange();
@@ -122,7 +134,27 @@ void PrettyPrint::Print_Decl_Raw(Decl *decl)
           decl->print(Out, PPolicy);
         }
       } else {
+        MacroInfo *noinline_info = nullptr;
+        if (Has_NoInline_Attr(decl)) {
+          /* If the code has a `noinline` macro defined, it conflicts with
+             clang's __attribute__((noinline)) attribute dump.  Hence we
+             have to undef it.  */
+          Preprocessor &pp = AST->getPreprocessor();
+          MacroWalker MW(pp);
+
+          /* Get the valid macro at the source location.  */
+          IdentifierInfo *noinline = pp.getIdentifierInfo("noinline");
+          noinline_info = MW.Get_Macro_Info(noinline, decl->getBeginLoc());
+          /* Only print it if the noinline macro is defined at location.  */
+          if (noinline_info) {
+            Out << "#undef noinline\n";
+          }
+        }
         decl->print(Out, LangOpts);
+        if (noinline_info) {
+          /* Redeclare the macro to the previous value.  */
+          PrettyPrint::Print_MacroInfo(noinline_info);
+        }
       }
     } else {
       Out << decl_source;
@@ -192,7 +224,7 @@ void PrettyPrint::Debug_InclusionDirective(InclusionDirective *include)
 void PrettyPrint::Print_MacroInfo(MacroInfo *info)
 {
   SourceRange range(info->getDefinitionLoc(), info->getDefinitionEndLoc());
-  llvm::outs() << " info: " << Get_Source_Text(range) << '\n';
+  Out << "#define " << Get_Source_Text(range) << '\n';
 }
 
 void PrettyPrint::Print_Attr(Attr *attr)

testsuite/small/attr-8.c

@@ -0,0 +1,13 @@
+/* { dg-options "-DCE_EXTRACT_FUNCTIONS=func_f -DCE_NO_EXTERNALIZATION" }*/
+#define MACRO 0
+
+/* Do this sort of blurry definition to confuse out clang-extract into dumping
+   the AST of the function.  */
+#define DEFINE_FUNCTION(name) __attribute__((noinline)) int func_##name(void) { return MACRO; }
+#define DEFINE_VARIABLE(name) int var_##name;
+#define DEFINE(f) DEFINE_VARIABLE(f) DEFINE_FUNCTION(f)
+
+DEFINE(f)
+
+/* { dg-final { scan-tree-dump "__attribute__\(\(noinline\)\)" } } */
+/* { dg-final { scan-tree-dump-not "#define noinline" } } */

testsuite/small/attr-9.c

@@ -0,0 +1,33 @@
+/* { dg-options "-DCE_EXTRACT_FUNCTIONS=func_f,g,h -DCE_NO_EXTERNALIZATION" }*/
+
+
+#define noinline SHOULD_NOT_BE_IN_THE_FINAL_OUTPUT
+
+#undef noinline
+#define noinline __attribute__((__noinline__))
+
+/* Do this sort of blurry definition to confuse out clang-extract into dumping
+   the AST of the function.  */
+#define DEFINE_FUNCTION(name) noinline int func_##name(void) { return 0; }
+#define DEFINE_VARIABLE(name) int var_##name;
+#define DEFINE(f) DEFINE_VARIABLE(f) DEFINE_FUNCTION(f)
+
+noinline int g()
+{
+  return 1;
+}
+
+DEFINE(f);
+
+noinline int h()
+{
+  return 2;
+}
+
+
+#undef noinline
+#define noinline SHOULD_NOT_BE_IN_THE_FINAL_OUTPUT
+
+/* { dg-final { scan-tree-dump "__attribute__\(\(noinline\)\) int func_f" } } */
+/* { dg-final { scan-tree-dump "#undef noinline" } } */
+/* { dg-final { scan-tree-dump-not "SHOULD_NOT_BE_IN_THE_FINAL_OUTPUT" } } */