Fix and test SubProgram handling.

Author: maleadt

src/debuginfo.jl

@@ -5,6 +5,9 @@ DEBUG_METADATA_VERSION() = API.LLVMDebugMetadataVersion()
 strip_debuginfo!(mod::Module) = API.LLVMStripModuleDebugInfo(mod)
 
 if version() >= v"8.0"
+function get_subprogram(func::Function)
+    ref = API.LLVMGetSubprogram(func)
+    ref==C_NULL ? nothing : Metadata(ref)
+end
 set_subprogram!(func::Function, sp::Metadata) = API.LLVMSetSubprogram(func, sp)
-get_subprogram(func::Function) = Metadata(API.LLVMGetSubprogram(func))
 end

test/debuginfo.jl

@@ -5,11 +5,16 @@ DEBUG_METADATA_VERSION()
 Context() do ctx
     if LLVM.version() < v"8.0"
         mod = parse(LLVM.Module,  """
-            define void @fun() !dbg !5 {
+            define void @foo() !dbg !5 {
             top:
               ret void, !dbg !7
             }
 
+            define void @bar() {
+            top:
+              ret void
+            }
+
             !llvm.module.flags = !{!0, !1}
             !llvm.dbg.cu = !{!2}
 
@@ -18,16 +23,21 @@ Context() do ctx
             !2 = distinct !DICompileUnit(language: DW_LANG_C89, file: !3, producer: "julia", isOptimized: true, runtimeVersion: 0, emissionKind: FullDebug, enums: !4)
             !3 = !DIFile(filename: "REPL[1]", directory: ".")
             !4 = !{}
-            !5 = distinct !DISubprogram(name: "foo", linkageName: "fun", scope: null, file: !3, line: 1, type: !6, isLocal: false, isDefinition: true, scopeLine: 1, isOptimized: true, unit: !2, variables: !4)
+            !5 = distinct !DISubprogram(name: "foo", linkageName: "foo", scope: null, file: !3, line: 1, type: !6, isLocal: false, isDefinition: true, scopeLine: 1, isOptimized: true, unit: !2, variables: !4)
             !6 = !DISubroutineType(types: !4)
             !7 = !DILocation(line: 1, scope: !5)""", ctx)
     else
         mod = parse(LLVM.Module,  """
-            define void @fun() !dbg !5 {
+            define void @foo() !dbg !5 {
             top:
               ret void, !dbg !7
             }
 
+            define void @bar() {
+            top:
+              ret void
+            }
+
             !llvm.module.flags = !{!0, !1}
             !llvm.dbg.cu = !{!2}
 
@@ -36,13 +46,24 @@ Context() do ctx
             !2 = distinct !DICompileUnit(language: DW_LANG_C89, file: !3, producer: "julia", isOptimized: true, runtimeVersion: 0, emissionKind: FullDebug, enums: !4)
             !3 = !DIFile(filename: "REPL[1]", directory: ".")
             !4 = !{}
-            !5 = distinct !DISubprogram(name: "foo", linkageName: "fun", scope: null, file: !3, line: 1, type: !6, isLocal: false, isDefinition: true, scopeLine: 1, isOptimized: true, unit: !2)
+            !5 = distinct !DISubprogram(name: "foo", linkageName: "foo", scope: null, file: !3, line: 1, type: !6, isLocal: false, isDefinition: true, scopeLine: 1, isOptimized: true, unit: !2)
             !6 = !DISubroutineType(types: !4)
             !7 = !DILocation(line: 1, scope: !5)""", ctx)
     end
 
-    fun = functions(mod)["fun"]
-    bb = entry(fun)
+    foo = functions(mod)["foo"]
+
+    if LLVM.version() >= v"8.0"
+        sp = LLVM.get_subprogram(foo)
+        @test sp !== nothing
+
+        bar = functions(mod)["bar"]
+        @test LLVM.get_subprogram(bar) === nothing
+        LLVM.set_subprogram!(bar, sp)
+        @test LLVM.get_subprogram(bar) == sp
+      end
+
+    bb = entry(foo)
     inst = first(instructions(bb))
 
     @test !isempty(metadata(inst))