Update subroutine methods to match functions

integration_tests/CMakeLists.txt

@@ -279,3 +279,4 @@ RUN(NAME recursion_01 LABELS gfortran llvm)
 
 RUN(NAME return_01 LABELS gfortran llvm)
 RUN(NAME return_02 LABELS gfortran llvm)
+RUN(NAME return_03 LABELS gfortran llvm)

integration_tests/return_03.f90

@@ -0,0 +1,17 @@
+program main
+    integer :: main_out = 999
+    call main1(main_out)
+    print *, "main1 called"
+    contains
+    subroutine main1(out_var)
+        integer :: out_var
+        integer :: i = 10
+        if (i .GT. 5) then
+            out_var = i
+            print *, "early return"
+            return  
+        end if
+        print *, "normal return"
+        out_var = i
+    end subroutine main1
+end program

src/lfortran/codegen/asr_to_llvm.cpp

@@ -1318,27 +1318,19 @@ class ASRToLLVMVisitor : public ASR::BaseVisitor<ASRToLLVMVisitor>
 
 
     void generate_subroutine(const ASR::Subroutine_t &x){
-        uint32_t h = get_hash((ASR::asr_t*)&x);
         bool interactive = (x.m_abi == ASR::abiType::Interactive);
         if (x.m_deftype == ASR::deftypeType::Implementation) {
 
             if (interactive) return;
 
             if (!prototype_only) {
-                llvm::Function* F = llvm_symtab_fn[h];
-                llvm::BasicBlock *BB = llvm::BasicBlock::Create(context,
-                        ".entry", F);
-                builder->SetInsertPoint(BB);
-
-                declare_args(x, *F);
-
-                declare_local_vars(x);
+                define_subroutine_entry(x);
 
                 for (size_t i=0; i<x.n_body; i++) {
                     this->visit_stmt(*x.m_body[i]);
                 }
 
-                builder->CreateRetVoid();
+                define_subroutine_exit(x);                
             }
         }
     }
@@ -1414,7 +1406,20 @@ class ASRToLLVMVisitor : public ASR::BaseVisitor<ASRToLLVMVisitor>
         declare_local_vars(x);
     }
 
-    inline  void define_function_exit(const ASR::Function_t& x) {
+
+    inline void define_subroutine_entry(const ASR::Subroutine_t& x) {
+        uint32_t h = get_hash((ASR::asr_t*)&x);
+        llvm::Function* F = llvm_symtab_fn[h];
+        llvm::BasicBlock *BB = llvm::BasicBlock::Create(context,
+                ".entry", F);
+        builder->SetInsertPoint(BB);
+
+        declare_args(x, *F);
+
+        declare_local_vars(x);
+    }
+
+    inline void define_function_exit(const ASR::Function_t& x) {
         if (early_return) {
             builder->CreateBr(if_return);
         }
@@ -1433,6 +1438,20 @@ class ASRToLLVMVisitor : public ASR::BaseVisitor<ASRToLLVMVisitor>
         builder->CreateRet(ret_val2);
     }
 
+
+    inline void define_subroutine_exit(const ASR::Subroutine_t& /*x*/) {
+        if (early_return) {
+            builder->CreateBr(if_return);
+        }
+
+        if (early_return) {
+            builder->SetInsertPoint(if_return);
+            early_return = false;
+        }
+
+        builder->CreateRetVoid();
+    }
+
     void generate_function(const ASR::Function_t &x){
         bool interactive = (x.m_abi == ASR::abiType::Interactive);
         if (x.m_deftype == ASR::deftypeType::Implementation ) {

tests/reference/llvm-return_03-fd5ee01.json

@@ -0,0 +1,13 @@
+{
+    "basename": "llvm-return_03-fd5ee01",
+    "cmd": "lfortran --show-llvm {infile} -o {outfile}",
+    "infile": "tests/../integration_tests/return_03.f90",
+    "infile_hash": "7d4898b23c807b105723b597c037469040fba56ee6c9891c93947d14",
+    "outfile": null,
+    "outfile_hash": null,
+    "stdout": "llvm-return_03-fd5ee01.stdout",
+    "stdout_hash": "f5de0548d6690b15f07d47f1b94e6af28ecf80b55404c37a4ea9f4e5",
+    "stderr": null,
+    "stderr_hash": null,
+    "returncode": 0
+}

tests/reference/llvm-return_03-fd5ee01.stdout

@@ -0,0 +1,48 @@
+; ModuleID = 'LFortran'
+source_filename = "LFortran"
+
+@0 = private unnamed_addr constant [13 x i8] c"early return\00", align 1
+@1 = private unnamed_addr constant [4 x i8] c"%s\0A\00", align 1
+@2 = private unnamed_addr constant [14 x i8] c"normal return\00", align 1
+@3 = private unnamed_addr constant [4 x i8] c"%s\0A\00", align 1
+@4 = private unnamed_addr constant [13 x i8] c"main1 called\00", align 1
+@5 = private unnamed_addr constant [4 x i8] c"%s\0A\00", align 1
+
+define void @main1(i32* %out_var) {
+.entry:
+  %i = alloca i32, align 4
+  store i32 10, i32* %i, align 4
+  %0 = load i32, i32* %i, align 4
+  %1 = icmp sgt i32 %0, 5
+  br i1 %1, label %then, label %else
+
+then:                                             ; preds = %.entry
+  %2 = load i32, i32* %i, align 4
+  store i32 %2, i32* %out_var, align 4
+  call void (i8*, ...) @_lfortran_printf(i8* getelementptr inbounds ([4 x i8], [4 x i8]* @1, i32 0, i32 0), i8* getelementptr inbounds ([13 x i8], [13 x i8]* @0, i32 0, i32 0))
+  br label %return
+
+return:                                           ; preds = %ifcont, %then
+  ret void
+
+else:                                             ; preds = %.entry
+  br label %ifcont
+
+ifcont:                                           ; preds = %else
+  call void (i8*, ...) @_lfortran_printf(i8* getelementptr inbounds ([4 x i8], [4 x i8]* @3, i32 0, i32 0), i8* getelementptr inbounds ([14 x i8], [14 x i8]* @2, i32 0, i32 0))
+  %3 = load i32, i32* %i, align 4
+  store i32 %3, i32* %out_var, align 4
+  br label %return
+}
+
+declare void @_lfortran_printf(i8*, ...)
+
+define i32 @main() {
+.entry:
+  %main_out = alloca i32, align 4
+  store i32 999, i32* %main_out, align 4
+  call void @main1(i32* %main_out)
+  call void (i8*, ...) @_lfortran_printf(i8* getelementptr inbounds ([4 x i8], [4 x i8]* @5, i32 0, i32 0), i8* getelementptr inbounds ([13 x i8], [13 x i8]* @4, i32 0, i32 0))
+  ret i32 0
+}
+

tests/tests.toml

@@ -1082,6 +1082,10 @@ llvm = true
 filename = "../integration_tests/return_02.f90"
 llvm = true
 
+[[test]]
+filename = "../integration_tests/return_03.f90"
+llvm = true
+
 [[test]]
 filename = "../integration_tests/modules_13.f90"
 llvm = true