[WebAssembly] Re-enable main-function signature rewriting

Re-enable the code to rewrite main-function signatures into
"int main(int argc, char *argv[])", but limited to only handling
the case of "int main(void)", so that it doesn't silently strip
an argument in the "int main(int argc, char *argv[], char *envp[])"
case.

This allows main to be called by C startup code, since WebAssembly
requires caller and callee signatures to match, so it can't rely
on passing main a different number of arguments than it expects.

Differential Revision: https://reviews.llvm.org/D57323

llvm-svn: 352479

1 files changed, 7 insertions, 9 deletions

diff --git a/llvm/test/CodeGen/WebAssembly/main-declaration.ll b/llvm/test/CodeGen/WebAssembly/main-declaration.ll
index f9d68db2bae..544f5588c50 100644
--- a/llvm/test/CodeGen/WebAssembly/main-declaration.ll
+++ b/llvm/test/CodeGen/WebAssembly/main-declaration.ll
@@ -1,20 +1,18 @@
-; RUN: llc < %s -asm-verbose=false -wasm-temporary-workarounds=false | FileCheck %s
+; RUN: llc < %s -asm-verbose=false | FileCheck %s
 
 ; Test main functions with alternate signatures.
 
 target datalayout = "e-m:e-p:32:32-i64:64-n32:64-S128"
 target triple = "wasm32-unknown-unknown"
 
-declare void @main()
+declare i32 @main()
 
-define void @foo() {
-  call void @main()
-  ret void
+define i32 @foo() {
+  %t = call i32 @main()
+  ret i32 %t
 }
 
-; CHECK-NOT:   __original_main
 ; CHECK-LABEL: foo:
-; CHECK-NEXT:    .functype foo () -> ()
-; CHECK-NEXT:    call main@FUNCTION
+; CHECK-NEXT:    .functype foo () -> (i32)
+; CHECK-NEXT:    call __original_main@FUNCTION
 ; CHECK-NEXT:    end_function
-; CHECK-NOT:   __original_main