Started working on lowering and declaration merging for C function bodies

Author: IsaacShelton

Diff for: src/asg/func.rs

@@ -9,6 +9,7 @@ pub struct Func {
     pub return_type: Type,
     pub stmts: Vec<Stmt>,
     pub is_foreign: bool,
+    pub is_exposed: bool,
     pub is_generic: bool,
     pub vars: VariableStorage,
     pub source: Source,

Diff for: src/ast/func/mod.rs

@@ -18,6 +18,7 @@ pub struct FuncHead {
     pub params: Params,
     pub return_type: Type,
     pub is_foreign: bool,
+    pub is_exposed: bool,
     pub source: Source,
     pub abide_abi: bool,
     pub tag: Option<Tag>,

Diff for: src/c/translation/function.rs

@@ -74,6 +74,12 @@ pub fn declare_function(
 
     match func_info.specifiers.storage_class {
         Some(StorageClassSpecifier::Typedef) => {
+            if body.is_some() {
+                return Err(
+                    ParseErrorKind::Misc("Cannot typedef function with body").at(declarator.source)
+                );
+            }
+
             let ast_type = ast::TypeKind::FuncPtr(ast::FuncPtr {
                 parameters: required,
                 return_type: Box::new(func_info.ast_type),
@@ -102,6 +108,7 @@ pub fn declare_function(
         },
         return_type: func_info.ast_type,
         is_foreign: true,
+        is_exposed: body.is_some(),
         source,
         abide_abi: true,
         tag: None,

Diff for: src/interpreter_env/mod.rs

@@ -29,6 +29,7 @@ fn thin_void_func(name: impl Into<String>, syscall_kind: InterpreterSyscallKind)
         return_type: void.clone(),
         abide_abi: false,
         is_foreign: false,
+        is_exposed: false,
         source,
         tag: None,
         privacy: Privacy::Public,
@@ -66,6 +67,7 @@ fn thin_cstring_func(
         return_type: void.clone(),
         abide_abi: false,
         is_foreign: false,
+        is_exposed: false,
         source,
         tag: None,
         privacy: Privacy::Public,
@@ -111,6 +113,7 @@ pub fn setup_build_system_interpreter_symbols(file: &mut AstFile) {
             params: Params::default(),
             return_type: void.clone(),
             is_foreign: false,
+            is_exposed: false,
             source,
             abide_abi: false,
             tag: Some(Tag::InterpreterEntryPoint),
@@ -230,6 +233,7 @@ pub fn setup_build_system_interpreter_symbols(file: &mut AstFile) {
             return_type: void.clone(),
             abide_abi: false,
             is_foreign: false,
+            is_exposed: false,
             source,
             tag: None,
             privacy: Privacy::Public,
@@ -274,6 +278,7 @@ pub fn setup_build_system_interpreter_symbols(file: &mut AstFile) {
             return_type: void.clone(),
             abide_abi: false,
             is_foreign: false,
+            is_exposed: false,
             source,
             tag: None,
             privacy: Privacy::Public,
@@ -312,6 +317,7 @@ pub fn setup_build_system_interpreter_symbols(file: &mut AstFile) {
             return_type: TypeKind::Named(Name::plain("Dependency"), vec![]).at(source),
             abide_abi: false,
             is_foreign: false,
+            is_exposed: false,
             source,
             tag: None,
             privacy: Privacy::Public,

Diff for: src/llvm_backend/functions/head.rs

@@ -13,10 +13,13 @@ use crate::{
 };
 use cstr::cstr;
 use llvm_sys::{
-    core::{LLVMAddFunction, LLVMFunctionType, LLVMSetFunctionCallConv, LLVMSetLinkage},
+    core::{
+        LLVMAddFunction, LLVMFunctionType, LLVMGetNamedFunction, LLVMSetFunctionCallConv,
+        LLVMSetLinkage,
+    },
     LLVMCallConv, LLVMLinkage,
 };
-use std::ffi::CString;
+use std::{ffi::CString, ptr::null_mut};
 
 pub unsafe fn create_func_heads(ctx: &mut BackendCtx) -> Result<(), BackendError> {
     for (func_ref, func) in ctx.ir_module.funcs.iter() {
@@ -62,19 +65,37 @@ pub unsafe fn create_func_heads(ctx: &mut BackendCtx) -> Result<(), BackendError
         };
 
         let name = CString::new(func.mangled_name.as_bytes()).unwrap();
-        let skeleton = LLVMAddFunction(
-            ctx.backend_module.get(),
-            name.as_ptr(),
-            function_type.pointer,
-        );
-        LLVMSetFunctionCallConv(skeleton, LLVMCallConv::LLVMCCallConv as u32);
 
-        let nounwind = create_enum_attribute(cstr!("nounwind"), 0);
-        add_func_attribute(skeleton, nounwind);
+        let existing = if func.is_foreign || func.is_exposed {
+            LLVMGetNamedFunction(ctx.backend_module.get(), name.as_ptr())
+        } else {
+            null_mut()
+        };
+
+        let skeleton = if existing.is_null() {
+            let skeleton = LLVMAddFunction(
+                ctx.backend_module.get(),
+                name.as_ptr(),
+                function_type.pointer,
+            );
+
+            LLVMSetFunctionCallConv(skeleton, LLVMCallConv::LLVMCCallConv as u32);
 
-        if !func.is_foreign && !func.is_exposed {
-            LLVMSetLinkage(skeleton, LLVMLinkage::LLVMPrivateLinkage);
-        }
+            let nounwind = create_enum_attribute(cstr!("nounwind"), 0);
+            add_func_attribute(skeleton, nounwind);
+
+            if !func.is_foreign && !func.is_exposed {
+                LLVMSetLinkage(skeleton, LLVMLinkage::LLVMPrivateLinkage);
+            }
+
+            skeleton
+        } else {
+            if func.is_foreign || func.is_exposed {
+                LLVMSetLinkage(existing, LLVMLinkage::LLVMExternalLinkage);
+            }
+
+            existing
+        };
 
         ctx.func_skeletons.insert(
             func_ref,

Diff for: src/lower/function.rs

@@ -115,7 +115,7 @@ pub fn lower_func_head(
     };
 
     let is_main = mangled_name == "main";
-    let is_exposed = is_main;
+    let is_exposed = func.is_exposed || is_main;
 
     Ok(ir_module.funcs.insert(
         func_ref,

Diff for: src/parser/parse_func.rs

@@ -25,13 +25,15 @@ impl<'a, I: Inflow<Token>> Parser<'a, I> {
         let source = self.input.advance().source;
 
         let mut is_foreign = false;
+        let mut is_exposed = false;
         let mut abide_abi = false;
         let mut privacy = Privacy::Protected;
         let mut givens = vec![];
 
         for annotation in annotations {
             match annotation.kind {
                 AnnotationKind::Foreign => is_foreign = true,
+                AnnotationKind::Exposed => is_exposed = true,
                 AnnotationKind::AbideAbi => abide_abi = true,
                 AnnotationKind::Public => privacy = Privacy::Public,
                 AnnotationKind::Private => privacy = Privacy::Private,
@@ -81,6 +83,7 @@ impl<'a, I: Inflow<Token>> Parser<'a, I> {
                 params,
                 return_type,
                 is_foreign,
+                is_exposed,
                 source,
                 abide_abi,
                 tag: None,

Diff for: src/pragma_section/parse.rs

@@ -111,6 +111,7 @@ impl PragmaSection {
                     params: Params::default(),
                     return_type: TypeKind::Void.at(source),
                     is_foreign: false,
+                    is_exposed: false,
                     source,
                     abide_abi: false,
                     tag: None,

Diff for: src/resolve/func_head.rs

@@ -117,7 +117,8 @@ pub fn create_func_head<'a>(
         params,
         return_type,
         stmts: vec![],
-        is_foreign: head.is_foreign,
+        is_foreign: head.is_foreign && !head.is_exposed,
+        is_exposed: head.is_exposed,
         vars: VariableStorage::new(),
         source: head.source,
         abide_abi: head.abide_abi,