[llvm] [WebAssemblyLowerEmscriptenEHSjLj] Don't assign import names to generated function declarations (PR #71599)

[Sam Clegg via llvm-commits]

https://github.com/sbc100 updated https://github.com/llvm/llvm-project/pull/71599

>From 33e3e7f34cd7f534cff0a5d0da11af78e01e6492 Mon Sep 17 00:00:00 2001
From: Sam Clegg <sbc at chromium.org>
Date: Tue, 7 Nov 2023 14:49:22 -0800
Subject: [PATCH] [WebAssemblyLowerEmscriptenEHSjLj] Don't assign import names
 to generated function declarations

These days we would prefer that the linker report errors when these
symbols are not defined.  Assigning import names like this tells the
linker not to report errors when these symbols are missing and simply
import them.  However, this leads to much less useful undefined symbol
errors after the linker is done.

Note that keep the old behavior for the `invoke_xxx` functions since
its not possible for is to declare all possible permutations ahead of
time in a library.

See https://github.com/emscripten-core/emscripten/pull/20536
---
 .../WebAssembly/WebAssemblyLowerEmscriptenEHSjLj.cpp     | 9 +++++++--
 llvm/test/CodeGen/WebAssembly/lower-em-ehsjlj-options.ll | 4 ----
 llvm/test/CodeGen/WebAssembly/lower-em-sjlj.ll           | 7 -------
 llvm/test/CodeGen/WebAssembly/lower-wasm-ehsjlj.ll       | 2 +-
 4 files changed, 8 insertions(+), 14 deletions(-)

diff --git a/llvm/lib/Target/WebAssembly/WebAssemblyLowerEmscriptenEHSjLj.cpp b/llvm/lib/Target/WebAssembly/WebAssemblyLowerEmscriptenEHSjLj.cpp
index 5e84fff351b23d1..3a2c8641db3e5d6 100644
--- a/llvm/lib/Target/WebAssembly/WebAssemblyLowerEmscriptenEHSjLj.cpp
+++ b/llvm/lib/Target/WebAssembly/WebAssemblyLowerEmscriptenEHSjLj.cpp
@@ -448,7 +448,12 @@ static std::string getSignature(FunctionType *FTy) {
 
 static Function *getEmscriptenFunction(FunctionType *Ty, const Twine &Name,
                                        Module *M) {
-  Function* F = Function::Create(Ty, GlobalValue::ExternalLinkage, Name, M);
+  return Function::Create(Ty, GlobalValue::ExternalLinkage, Name, M);
+}
+
+static Function *getInvokeFunction(FunctionType *Ty, const Twine &Name,
+                                   Module *M) {
+  Function *F = getEmscriptenFunction(Ty, Name, M);
   // Tell the linker that this function is expected to be imported from the
   // 'env' module.
   if (!F->hasFnAttribute("wasm-import-module")) {
@@ -591,7 +596,7 @@ Function *WebAssemblyLowerEmscriptenEHSjLj::getInvokeWrapper(CallBase *CI) {
 
   FunctionType *FTy = FunctionType::get(CalleeFTy->getReturnType(), ArgTys,
                                         CalleeFTy->isVarArg());
-  Function *F = getEmscriptenFunction(FTy, "__invoke_" + Sig, M);
+  Function *F = getInvokeFunction(FTy, "__invoke_" + Sig, M);
   InvokeWrappers[Sig] = F;
   return F;
 }
diff --git a/llvm/test/CodeGen/WebAssembly/lower-em-ehsjlj-options.ll b/llvm/test/CodeGen/WebAssembly/lower-em-ehsjlj-options.ll
index aa4d87756c87d0a..138afe075ceecb1 100644
--- a/llvm/test/CodeGen/WebAssembly/lower-em-ehsjlj-options.ll
+++ b/llvm/test/CodeGen/WebAssembly/lower-em-ehsjlj-options.ll
@@ -13,11 +13,7 @@ target triple = "wasm32-unknown-unknown"
 ; EH-NOT: .import_name  __invoke_void_i32
 
 ; SJLJ: .functype  emscripten_longjmp (i32, i32) -> ()
-; SJLJ: .import_module  emscripten_longjmp, env
-; SJLJ: .import_name  emscripten_longjmp, emscripten_longjmp
 ; SJLJ-NOT: .functype  emscripten_longjmp_jmpbuf
-; SJLJ-NOT: .import_module  emscripten_longjmp_jmpbuf
-; SJLJ-NOT: .import_name  emscripten_longjmp_jmpbuf
 
 %struct.__jmp_buf_tag = type { [6 x i32], i32, [32 x i32] }
 
diff --git a/llvm/test/CodeGen/WebAssembly/lower-em-sjlj.ll b/llvm/test/CodeGen/WebAssembly/lower-em-sjlj.ll
index 7115b01ed1618e9..5bb052b65a8d3ae 100644
--- a/llvm/test/CodeGen/WebAssembly/lower-em-sjlj.ll
+++ b/llvm/test/CodeGen/WebAssembly/lower-em-sjlj.ll
@@ -305,13 +305,6 @@ attributes #0 = { returns_twice }
 attributes #1 = { noreturn }
 attributes #2 = { nounwind }
 attributes #3 = { allocsize(0) }
-; CHECK-DAG: attributes #{{[0-9]+}} = { nounwind "wasm-import-module"="env" "wasm-import-name"="getTempRet0" }
-; CHECK-DAG: attributes #{{[0-9]+}} = { nounwind "wasm-import-module"="env" "wasm-import-name"="setTempRet0" }
-; CHECK-DAG: attributes #{{[0-9]+}} = { "wasm-import-module"="env" "wasm-import-name"="__invoke_void" }
-; CHECK-DAG: attributes #{{[0-9]+}} = { "wasm-import-module"="env" "wasm-import-name"="saveSetjmp" }
-; CHECK-DAG: attributes #{{[0-9]+}} = { "wasm-import-module"="env" "wasm-import-name"="testSetjmp" }
-; CHECK-DAG: attributes #{{[0-9]+}} = { noreturn "wasm-import-module"="env" "wasm-import-name"="emscripten_longjmp" }
-; CHECK-DAG: attributes #{{[0-9]+}} = { "wasm-import-module"="env" "wasm-import-name"="__invoke_ptr_i32_ptr" }
 ; CHECK-DAG: attributes #[[ALLOCSIZE_ATTR]] = { allocsize(1) }
 
 !llvm.dbg.cu = !{!2}
diff --git a/llvm/test/CodeGen/WebAssembly/lower-wasm-ehsjlj.ll b/llvm/test/CodeGen/WebAssembly/lower-wasm-ehsjlj.ll
index 25471eb50081b39..ce417a5db26308b 100644
--- a/llvm/test/CodeGen/WebAssembly/lower-wasm-ehsjlj.ll
+++ b/llvm/test/CodeGen/WebAssembly/lower-wasm-ehsjlj.ll
@@ -109,7 +109,7 @@ catch:                                            ; preds = %catch.start
   catchret from %2 to label %catchret.dest
 ; CHECK: catch:                                            ; preds = %catch.start
 ; CHECK-NEXT:   %exn = load ptr, ptr %exn.slot15, align 4
-; CHECK-NEXT:   %5 = call ptr @__cxa_begin_catch(ptr %exn) #7 [ "funclet"(token %2) ]
+; CHECK-NEXT:   %5 = call ptr @__cxa_begin_catch(ptr %exn) #3 [ "funclet"(token %2) ]
 ; CHECK-NEXT:   invoke void @__cxa_end_catch() [ "funclet"(token %2) ]
 ; CHECK-NEXT:           to label %.noexc unwind label %catch.dispatch.longjmp