[PATCH] D77809: [Analyzer] Include typedef statements in CFG build.

[Balázs Kéri via Phabricator via cfe-commits]

balazske created this revision.
Herald added subscribers: cfe-commits, ASDenysPetrov, martong, Charusso, gamesh411, dkrupp, donat.nagy, Szelethus, mikhail.ramalho, a.sidorin, szepet, baloghadamsoftware, xazax.hun.
Herald added a reviewer: Szelethus.
Herald added a project: clang.

Array size expressions in typedef statements with a VLA
(variable-length array) are handled from now as in plain
(non-typedef) VLA declarations.
(Type-alias is not handled.)

I am not familiar with the CFGBuilder, the new code
only seems to work. Maybe somebody can tell how to
make a better solution (if needed) for the problem.

The fix is useful to have the values used at VLA sizes
available for the analyzer and checkers.
The code works similar as `CodeGenFunction::emitDecl`
that processes typedef and type-alias VLA size expressions
at place of the typedef or type-alias statement.


Repository:
  rG LLVM Github Monorepo

https://reviews.llvm.org/D77809

Files:
  clang/lib/Analysis/CFG.cpp


Index: clang/lib/Analysis/CFG.cpp
===================================================================
--- clang/lib/Analysis/CFG.cpp
+++ clang/lib/Analysis/CFG.cpp
@@ -2839,6 +2839,19 @@
 /// DeclStmts and initializers in them.
 CFGBlock *CFGBuilder::VisitDeclSubExpr(DeclStmt *DS) {
   assert(DS->isSingleDecl() && "Can handle single declarations only.");
+
+  if (const auto *TDD = dyn_cast<TypedefDecl>(DS->getSingleDecl())) {
+    // If we encounter a VLA in typedef, then process its size expressions.
+    CFGBlock *LastBlock = Block;
+    for (const VariableArrayType *VA =
+             FindVA(TDD->getUnderlyingType().getTypePtr());
+         VA != nullptr; VA = FindVA(VA->getElementType().getTypePtr())) {
+      if (CFGBlock *newBlock = addStmt(VA->getSizeExpr()))
+        LastBlock = newBlock;
+    }
+    return LastBlock;
+  }
+
   VarDecl *VD = dyn_cast<VarDecl>(DS->getSingleDecl());
 
   if (!VD) {


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