[WebAssembly] Handle _setjmp and _longjmp in SjLj

In some platforms `_setjmp` and `_longjmp` are used instead of `setjmp`
and `longjmp`. This CL adds support for them.

Fixes https://github.com/emscripten-core/emscripten/issues/14999.

Reviewed By: dschuff

Differential Revision: https://reviews.llvm.org/D109669

1 files changed, 27 insertions, 0 deletions

diff --git a/llvm/lib/Target/WebAssembly/WebAssemblyLowerEmscriptenEHSjLj.cpp b/llvm/lib/Target/WebAssembly/WebAssemblyLowerEmscriptenEHSjLj.cpp
index dd8909b..33a9c60 100644
--- a/llvm/lib/Target/WebAssembly/WebAssemblyLowerEmscriptenEHSjLj.cpp
+++ b/llvm/lib/Target/WebAssembly/WebAssemblyLowerEmscriptenEHSjLj.cpp
@@ -831,6 +831,33 @@ bool WebAssemblyLowerEmscriptenEHSjLj::runOnModule(Module &M) {
   Function *SetjmpF = M.getFunction("setjmp");
   Function *LongjmpF = M.getFunction("longjmp");
 
+  // In some platforms _setjmp and _longjmp are used instead. Change these to
+  // use setjmp/longjmp instead, because we laster detect these functions by
+  // their names.
+  Function *SetjmpF2 = M.getFunction("_setjmp");
+  Function *LongjmpF2 = M.getFunction("_longjmp");
+  if (SetjmpF2) {
+    if (SetjmpF) {
+      if (SetjmpF->getFunctionType() != SetjmpF2->getFunctionType())
+        report_fatal_error("setjmp and _setjmp have different function types");
+    } else {
+      SetjmpF = Function::Create(SetjmpF2->getFunctionType(),
+                                 GlobalValue::ExternalLinkage, "setjmp", M);
+    }
+    SetjmpF2->replaceAllUsesWith(SetjmpF);
+  }
+  if (LongjmpF2) {
+    if (LongjmpF) {
+      if (LongjmpF->getFunctionType() != LongjmpF2->getFunctionType())
+        report_fatal_error(
+            "longjmp and _longjmp have different function types");
+    } else {
+      LongjmpF = Function::Create(LongjmpF2->getFunctionType(),
+                                  GlobalValue::ExternalLinkage, "setjmp", M);
+    }
+    LongjmpF2->replaceAllUsesWith(LongjmpF);
+  }
+
   auto *TPC = getAnalysisIfAvailable<TargetPassConfig>();
   assert(TPC && "Expected a TargetPassConfig");
   auto &TM = TPC->getTM<WebAssemblyTargetMachine>();