[llvm] r292645 - [WebAssembly] Don't create bitcast-wrappers for varargs.

[Dan Gohman via llvm-commits]

Author: djg
Date: Fri Jan 20 14:50:29 2017
New Revision: 292645

URL: http://llvm.org/viewvc/llvm-project?rev=292645&view=rev
Log:
[WebAssembly] Don't create bitcast-wrappers for varargs.

WebAssembly varargs functions use a significantly different ABI than
non-varargs functions, and the current code in
WebAssemblyFixFunctionBitcasts doesn't handle that difference. For now,
just avoid creating wrapper functions in the presence of varargs.

Modified:
    llvm/trunk/lib/Target/WebAssembly/WebAssemblyFixFunctionBitcasts.cpp
    llvm/trunk/test/CodeGen/WebAssembly/function-bitcasts.ll

Modified: llvm/trunk/lib/Target/WebAssembly/WebAssemblyFixFunctionBitcasts.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Target/WebAssembly/WebAssemblyFixFunctionBitcasts.cpp?rev=292645&r1=292644&r2=292645&view=diff
==============================================================================
--- llvm/trunk/lib/Target/WebAssembly/WebAssemblyFixFunctionBitcasts.cpp (original)
+++ llvm/trunk/lib/Target/WebAssembly/WebAssemblyFixFunctionBitcasts.cpp Fri Jan 20 14:50:29 2017
@@ -148,6 +148,11 @@ bool FixFunctionBitcasts::runOnModule(Mo
     if (!Ty)
       continue;
 
+    // Wasm varargs are not ABI-compatible with non-varargs. Just ignore
+    // such casts for now.
+    if (Ty->isVarArg() || F->isVarArg())
+      continue;
+
     auto Pair = Wrappers.insert(std::make_pair(std::make_pair(F, Ty), nullptr));
     if (Pair.second)
       Pair.first->second = CreateWrapper(F, Ty);

Modified: llvm/trunk/test/CodeGen/WebAssembly/function-bitcasts.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/CodeGen/WebAssembly/function-bitcasts.ll?rev=292645&r1=292644&r2=292645&view=diff
==============================================================================
--- llvm/trunk/test/CodeGen/WebAssembly/function-bitcasts.ll (original)
+++ llvm/trunk/test/CodeGen/WebAssembly/function-bitcasts.ll Fri Jan 20 14:50:29 2017
@@ -22,6 +22,15 @@ target triple = "wasm32-unknown-unknown"
 ; CHECK-NEXT: call        foo3 at FUNCTION{{$}}
 ; CHECK-NEXT: .endfunc
 
+; CHECK-LABEL: test_varargs:
+; CHECK-NEXT: .local      i32
+; CHECK:      store
+; CHECK:      i32.const   $push[[L3:[0-9]+]]=, 0{{$}}
+; CHECK-NEXT: call        vararg at FUNCTION, $pop[[L3]]{{$}}
+; CHECK-NEXT: i32.const   $push[[L4:[0-9]+]]=, 0{{$}}
+; CHECK-NEXT: i32.store   0($[[L5:[0-9]+]]), $pop[[L4]]{{$}}
+; CHECK-NEXT: call        plain at FUNCTION, $[[L5]]{{$}}
+
 ; CHECK-LABEL: .Lbitcast:
 ; CHECK-NEXT: .local      i32
 ; CHECK-NEXT: call        has_i32_arg at FUNCTION, $0{{$}}
@@ -45,6 +54,8 @@ target triple = "wasm32-unknown-unknown"
 
 declare void @has_i32_arg(i32)
 declare i32 @has_i32_ret()
+declare void @vararg(...)
+declare void @plain(i32)
 
 declare void @foo0()
 declare void @foo1()
@@ -70,3 +81,9 @@ entry:
 
   ret void
 }
+
+define void @test_varargs() {
+  call void bitcast (void (...)* @vararg to void (i32)*)(i32 0)
+  call void (...) bitcast (void (i32)* @plain to void (...)*)(i32 0)
+  ret void
+}