[clang] [CIR] Support for static variables (PR #143980)

[Erich Keane via cfe-commits]

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@@ -219,6 +236,252 @@ void CIRGenFunction::emitVarDecl(const VarDecl &d) {
   return emitAutoVarDecl(d);
 }
 
+static std::string getStaticDeclName(CIRGenModule &cgm, const VarDecl &d) {
+  if (cgm.getLangOpts().CPlusPlus)
+    return cgm.getMangledName(&d).str();
+
+  // If this isn't C++, we don't need a mangled name, just a pretty one.
+  assert(!d.isExternallyVisible() && "name shouldn't matter");
+  std::string contextName;
+  const DeclContext *dc = d.getDeclContext();
+  if (auto *cd = dyn_cast<CapturedDecl>(dc))
+    dc = cast<DeclContext>(cd->getNonClosureContext());
+  if (const auto *fd = dyn_cast<FunctionDecl>(dc))
+    contextName = std::string(cgm.getMangledName(fd));
+  else if (isa<BlockDecl>(dc))
+    cgm.errorNYI(d.getSourceRange(), "block decl context for static var");
+  else if (isa<ObjCMethodDecl>(dc))
+    cgm.errorNYI(d.getSourceRange(), "ObjC decl context for static var");
+  else
+    cgm.errorNYI(d.getSourceRange(), "Unknown context for static var decl");
+
+  contextName += "." + d.getNameAsString();
+  return contextName;
+}
+
+// TODO(cir): LLVM uses a Constant base class. Maybe CIR could leverage an
+// interface for all constants?
+cir::GlobalOp
+CIRGenModule::getOrCreateStaticVarDecl(const VarDecl &d,
+                                       cir::GlobalLinkageKind linkage) {
+  // In general, we don't always emit static var decls once before we reference
+  // them. It is possible to reference them before emitting the function that
+  // contains them, and it is possible to emit the containing function multiple
+  // times.
+  if (cir::GlobalOp existingGV = getStaticLocalDeclAddress(&d))
+    return existingGV;
+
+  QualType ty = d.getType();
+  assert(ty->isConstantSizeType() && "VLAs can't be static");
+
+  // Use the label if the variable is renamed with the asm-label extension.
+  std::string name;
+  if (d.hasAttr<AsmLabelAttr>())
+    errorNYI(d.getSourceRange(), "getOrCreateStaticVarDecl: asm label");
+  else
+    name = getStaticDeclName(*this, d);
----------------
erichkeane wrote:

I'm on the fence about a suggestion here... just always init 'name' above and let AsmLabelAttr errorNYI for now, and whoever comes to fix this can figure out if the branch is reasonable.  WDYT?

https://github.com/llvm/llvm-project/pull/143980