[WebAssembly] Prevent inline assembly from being mangled by SjLj

Summary:
Before, inline assembly gets mangled by the SjLj transformation.

For example, in a function with setjmp/longjmp, this LLVM IR code

    call void asm sideeffect "", ""()

would be transformed into

    call void @__invoke_void(void ()* asm sideeffect "", "")

This is invalid, and results in the error:

    Cannot take the address of an inline asm!

In this diff, we skip the transformation for inline assembly.

Reviewers: aheejin, tlively

Subscribers: dschuff, sbc100, jgravelle-google, hiraditya, sunfish, llvm-commits

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D64115

llvm-svn: 364985

1 files changed, 7 insertions, 0 deletions

diff --git a/llvm/lib/Target/WebAssembly/WebAssemblyLowerEmscriptenEHSjLj.cpp b/llvm/lib/Target/WebAssembly/WebAssemblyLowerEmscriptenEHSjLj.cpp
index 7ab8e361a8b..960d5134f6e 100644
--- a/llvm/lib/Target/WebAssembly/WebAssemblyLowerEmscriptenEHSjLj.cpp
+++ b/llvm/lib/Target/WebAssembly/WebAssemblyLowerEmscriptenEHSjLj.cpp
@@ -485,6 +485,13 @@ bool WebAssemblyLowerEmscriptenEHSjLj::canLongjmp(Module &M,
     if (CalleeF->isIntrinsic())
       return false;
 
+  // Attempting to transform inline assembly will result in something like:
+  //     call void @__invoke_void(void ()* asm ...)
+  // which is invalid because inline assembly blocks do not have addresses
+  // and can't be passed by pointer. The result is a crash with illegal IR.
+  if (isa<InlineAsm>(Callee))
+    return false;
+
   // The reason we include malloc/free here is to exclude the malloc/free
   // calls generated in setjmp prep / cleanup routines.
   Function *SetjmpF = M.getFunction("setjmp");