Separate compilation and linker phases (#376)

Separate between compilation and linker phases to allow deploy time
linking and back-porting era compiler changes to fix #91. Unlinked
contract binaries (caused by missing libraries or missing factory
dependencies in turn) are emitted as raw ELF object.

Few drive by fixes:
- #98
- A compiler panic on missing libraries definitions.
- Fixes some incosistent type forwarding in JSON output (empty string
vs. null object).
- Remove the unused fallback for size optimization setting.
- Remove the broken `--lvm-ir`  mode.
- CI workflow fixes.

---------

Signed-off-by: Cyrill Leutwiler <bigcyrill@hotmail.com>
Signed-off-by: xermicus <bigcyrill@hotmail.com>
Signed-off-by: xermicus <cyrill@parity.io>

crates/llvm-context/src/polkavm/context/runtime.rs

@@ -8,14 +8,10 @@ use crate::polkavm::context::function::declaration::Declaration;
 use crate::polkavm::context::function::Function;
 use crate::polkavm::context::Attribute;
 use crate::polkavm::context::Context;
-use crate::polkavm::Dependency;
 
 /// The revive runtime function interface simplifies declaring runtime functions
 /// and code emitting by providing helpful default implementations.
-pub trait RuntimeFunction<D>
-where
-    D: Dependency + Clone,
-{
+pub trait RuntimeFunction {
     /// The function name.
     const NAME: &'static str;
 
@@ -26,10 +22,10 @@ where
     ];
 
     /// The function type.
-    fn r#type<'ctx>(context: &Context<'ctx, D>) -> inkwell::types::FunctionType<'ctx>;
+    fn r#type<'ctx>(context: &Context<'ctx>) -> inkwell::types::FunctionType<'ctx>;
 
     /// Declare the function.
-    fn declare(&self, context: &mut Context<D>) -> anyhow::Result<()> {
+    fn declare(&self, context: &mut Context) -> anyhow::Result<()> {
         let function = context.add_function(
             Self::NAME,
             Self::r#type(context),
@@ -54,7 +50,7 @@ where
     }
 
     /// Get the function declaration.
-    fn declaration<'ctx>(context: &Context<'ctx, D>) -> Declaration<'ctx> {
+    fn declaration<'ctx>(context: &Context<'ctx>) -> Declaration<'ctx> {
         context
             .get_function(Self::NAME)
             .unwrap_or_else(|| panic!("runtime function {} should be declared", Self::NAME))
@@ -63,7 +59,7 @@ where
     }
 
     /// Emit the function.
-    fn emit(&self, context: &mut Context<D>) -> anyhow::Result<()> {
+    fn emit(&self, context: &mut Context) -> anyhow::Result<()> {
         context.set_current_function(Self::NAME, None)?;
         context.set_basic_block(context.current_function().borrow().entry_block());
 
@@ -78,13 +74,13 @@ where
     /// Emit the function body.
     fn emit_body<'ctx>(
         &self,
-        context: &mut Context<'ctx, D>,
+        context: &mut Context<'ctx>,
     ) -> anyhow::Result<Option<inkwell::values::BasicValueEnum<'ctx>>>;
 
     /// Emit the function return instructions.
     fn emit_epilogue<'ctx>(
         &self,
-        context: &mut Context<'ctx, D>,
+        context: &mut Context<'ctx>,
         return_value: Option<inkwell::values::BasicValueEnum<'ctx>>,
     ) {
         let return_block = context.current_function().borrow().return_block();
@@ -98,7 +94,7 @@ where
 
     /// Get the nth function paramater.
     fn paramater<'ctx>(
-        context: &Context<'ctx, D>,
+        context: &Context<'ctx>,
         index: usize,
     ) -> inkwell::values::BasicValueEnum<'ctx> {
         let name = Self::NAME;