Add function signature to code_native and code_llvm

Author: pchintalapudi

src/codegen.cpp

@@ -7447,6 +7447,14 @@ static jl_llvm_functions_t
         declarations.functionObject = needsparams ? "jl_fptr_sparam" : "jl_fptr_args";
     }
 
+    if (ctx.emission_context.debug_level >= 2 && lam->def.method && jl_is_method(lam->def.method) && lam->specTypes != (jl_value_t*)jl_emptytuple_type) {
+        ios_t sigbuf;
+        ios_mem(&sigbuf, 0);
+        jl_static_show_func_sig((JL_STREAM*) &sigbuf, (jl_value_t*)lam->specTypes);
+        f->addFnAttr("julia.fsig", StringRef(sigbuf.buf, sigbuf.size));
+        ios_close(&sigbuf);
+    }
+
     AttrBuilder FnAttrs(ctx.builder.getContext(), f->getAttributes().getFnAttrs());
     AttrBuilder RetAttrs(ctx.builder.getContext(), f->getAttributes().getRetAttrs());
 

src/disasm.cpp

@@ -363,6 +363,10 @@ class LineNumberAnnotatedWriter : public AssemblyAnnotationWriter {
 void LineNumberAnnotatedWriter::emitFunctionAnnot(
       const Function *F, formatted_raw_ostream &Out)
 {
+    if (F->hasFnAttribute("julia.fsig")) {
+        auto sig = F->getFnAttribute("julia.fsig").getValueAsString();
+        Out << "; Function Signature: " << sig << "\n";
+    }
     InstrLoc = nullptr;
     DISubprogram *FuncLoc = F->getSubprogram();
     if (!FuncLoc) {