[PATCH] D79743: [clang][asm goto][slh] Warn if asm goto + SLH

[Zola Bridges via Phabricator via cfe-commits]

zbrid created this revision.
zbrid added reviewers: mattdr, rsmith.
Herald added a project: clang.
Herald added a subscriber: cfe-commits.

Asm goto is not supported by SLH. Warn if an instance of asm goto is detected
while SLH is enabled.

Test included.


Repository:
  rG LLVM Github Monorepo

https://reviews.llvm.org/D79743

Files:
  clang/include/clang/Basic/DiagnosticCommonKinds.td
  clang/lib/CodeGen/CGStmt.cpp
  clang/test/Sema/asm-goto-slh.cpp


Index: clang/test/Sema/asm-goto-slh.cpp
===================================================================
--- /dev/null
+++ clang/test/Sema/asm-goto-slh.cpp
@@ -0,0 +1,5 @@
+// RUN: %clang_cc1 %s -mspeculative-load-hardening -triple x86_64-pc-linux-gnu -emit-llvm -S
+
+void f() {
+  __asm goto("movl %ecx, %edx"); // expected-warning {{speculative load hardening does not support use of GCC asm goto. asm goto detected with SLH}}
+}
Index: clang/lib/CodeGen/CGStmt.cpp
===================================================================
--- clang/lib/CodeGen/CGStmt.cpp
+++ clang/lib/CodeGen/CGStmt.cpp
@@ -2300,6 +2300,10 @@
                          /* IsAlignStack */ false, AsmDialect);
   std::vector<llvm::Value*> RegResults;
   if (IsGCCAsmGoto) {
+    const auto LO = getLangOpts();
+    if (LO.SpeculativeLoadHardening)
+      CGM.getDiags().Report(S.getAsmLoc(),
+                            diag::warn_slh_does_not_support_gcc_asm_goto);
     llvm::CallBrInst *Result =
         Builder.CreateCallBr(IA, Fallthrough, Transfer, Args);
     EmitBlock(Fallthrough);
Index: clang/include/clang/Basic/DiagnosticCommonKinds.td
===================================================================
--- clang/include/clang/Basic/DiagnosticCommonKinds.td
+++ clang/include/clang/Basic/DiagnosticCommonKinds.td
@@ -243,6 +243,10 @@
   def warn_stack_clash_protection_inline_asm : Warning<
     "Unable to protect inline asm that clobbers stack pointer against stack clash">,
     InGroup<DiagGroup<"stack-protector">>;
+
+  def warn_slh_does_not_support_gcc_asm_goto : Warning<
+    "speculative load hardening does not support use of GCC asm goto. asm goto "
+        "detected with SLH">;
 }
 
 // Sema && Serialization


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