[PATCH] D138514: Sema: diagnose PMFs passed through registers to inline assembly

[Saleem Abdulrasool via Phabricator via cfe-commits]

compnerd created this revision.
compnerd added a reviewer: aaron.ballman.
compnerd added a project: clang.
Herald added a project: All.
compnerd requested review of this revision.

The itanium ABI represents the PMF as a pair of pointers.  As such the
structure cannot be passed through a single register.  Diagnose such
cases in the frontend rather than trying to generate IR to perform this
operation.

Fixes: 59033


Repository:
  rG LLVM Github Monorepo

https://reviews.llvm.org/D138514

Files:
  clang/include/clang/Basic/DiagnosticSemaKinds.td
  clang/lib/Sema/SemaStmtAsm.cpp
  clang/test/Sema/gnu-asm-pmf.cpp


Index: clang/test/Sema/gnu-asm-pmf.cpp
===================================================================
--- /dev/null
+++ clang/test/Sema/gnu-asm-pmf.cpp
@@ -0,0 +1,36 @@
+// RUN: %clang_cc1 -triple x86_64-unknown-windows-msvc -std=c++2b -fsyntax-only -verify %s -DMICROSOFT_ABI
+// RUN: %clang_cc1 -triple x86_64-unknown-windows-itanium -std=c++2b -fsyntax-only -verify %s -DITANIUM_ABI
+
+#if defined(MICROSOFT_ABI)
+// expected-no-diagnostics
+#endif
+
+struct S {
+  void operator()() {}
+};
+
+struct T {
+  virtual void operator()() {}
+};
+
+struct U {
+  static void operator()() {}
+};
+
+auto L = [](){};
+
+void f() {
+  __asm__ __volatile__ ("" : : "r"(&decltype(L)::operator()));
+#if defined(ITANIUM_ABI)
+  // expected-error at -2{{cannot pass pointer-to-member through a register on this ABI}}
+#endif
+  __asm__ __volatile__ ("" : : "r"(&S::operator()));
+#if defined(ITANIUM_ABI)
+  // expected-error at -2{{cannot pass pointer-to-member through a register on this ABI}}
+#endif
+  __asm__ __volatile__ ("" : : "r"(&T::operator()));
+#if defined(ITANIUM_ABI)
+  // expected-error at -2{{cannot pass pointer-to-member through a register on this ABI}}
+#endif
+  __asm__ __volatile__ ("" : : "r"(U::operator()));
+}
Index: clang/lib/Sema/SemaStmtAsm.cpp
===================================================================
--- clang/lib/Sema/SemaStmtAsm.cpp
+++ clang/lib/Sema/SemaStmtAsm.cpp
@@ -377,6 +377,16 @@
 
     Expr *InputExpr = Exprs[i];
 
+    if (!Context.getTargetInfo().getCXXABI().isMicrosoft())
+      if (const auto *UO = dyn_cast<UnaryOperator>(InputExpr))
+        if (UO->getOpcode() == UO_AddrOf)
+          if (const auto *DRE = dyn_cast<DeclRefExpr>(UO->getSubExpr()))
+            if (const auto *CMD = dyn_cast<CXXMethodDecl>(DRE->getDecl()))
+              if (CMD->isInstance())
+                return StmtError(Diag(InputExpr->getBeginLoc(),
+                                      diag::err_asm_pmf_in_input)
+                                 << InputExpr->getSourceRange());
+
     // Referring to parameters is not allowed in naked functions.
     if (CheckNakedParmReference(InputExpr, *this))
       return StmtError();
Index: clang/include/clang/Basic/DiagnosticSemaKinds.td
===================================================================
--- clang/include/clang/Basic/DiagnosticSemaKinds.td
+++ clang/include/clang/Basic/DiagnosticSemaKinds.td
@@ -8842,6 +8842,8 @@
 
 // inline asm.
 let CategoryName = "Inline Assembly Issue" in {
+  def err_asm_pmf_in_input
+    : Error<"cannot pass pointer-to-member through a register on this ABI">;
   def err_asm_invalid_lvalue_in_output : Error<"invalid lvalue in asm output">;
   def err_asm_invalid_output_constraint : Error<
     "invalid output constraint '%0' in asm">;


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