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/solc-json-interface/src/standard_json/input/settings/selection/mod.rs

@@ -7,24 +7,33 @@ use std::collections::BTreeMap;
 use serde::Deserialize;
 use serde::Serialize;
 
+use self::file::flag::Flag;
 use self::file::File as FileSelection;
 
 /// The `solc --standard-json` output selection.
 #[derive(Clone, Debug, Serialize, Deserialize, Default, PartialEq)]
 pub struct Selection {
     /// Only the 'all' wildcard is available for robustness reasons.
-    #[serde(rename = "*", skip_serializing_if = "Option::is_none")]
-    all: Option<FileSelection>,
+    #[serde(default, rename = "*", skip_serializing_if = "FileSelection::is_empty")]
+    all: FileSelection,
 
     #[serde(skip_serializing_if = "BTreeMap::is_empty", flatten)]
     pub files: BTreeMap<String, FileSelection>,
 }
 
 impl Selection {
+    /// Creates the selection with arbitrary flags.
+    pub fn new(flags: Vec<Flag>) -> Self {
+        Self {
+            all: FileSelection::new(flags),
+            files: Default::default(),
+        }
+    }
+
     /// Creates the selection required by our compilation process.
     pub fn new_required() -> Self {
         Self {
-            all: Some(FileSelection::new_required()),
+            all: FileSelection::new_required(),
             files: BTreeMap::new(),
         }
     }
@@ -32,76 +41,35 @@ impl Selection {
     /// Creates the selection required for test compilation (includes EVM bytecode).
     pub fn new_required_for_tests() -> Self {
         Self {
-            all: Some(FileSelection::new_required_for_tests()),
+            all: FileSelection::new_required_for_tests(),
             files: BTreeMap::new(),
         }
     }
 
-    /// Extends the user's output selection with flag required by our compilation process.
-    pub fn extend_with_required(&mut self) -> &mut Self {
-        self.all
-            .get_or_insert_with(FileSelection::new_required)
-            .extend_with_required();
-        for (_, v) in self.files.iter_mut() {
-            v.extend_with_required();
-        }
+    /// Creates the selection required by Yul validation process.
+    pub fn new_yul_validation() -> Self {
+        Self::new(vec![Flag::EVM])
+    }
+
+    /// Extends the output selection with another one.
+    pub fn extend(&mut self, other: Self) -> &mut Self {
+        self.all.extend(other.all);
         self
     }
-}
 
-#[cfg(test)]
-mod test {
-    use std::collections::BTreeMap;
-
-    use crate::SolcStandardJsonInputSettingsSelectionFile;
-
-    use super::Selection;
-
-    #[test]
-    fn per_file() {
-        let init = Selection {
-            all: None,
-            files: BTreeMap::from([(
-                "Test".to_owned(),
-                SolcStandardJsonInputSettingsSelectionFile::new_required(),
-            )]),
-        };
-
-        let deser = serde_json::to_string(&init)
-            .and_then(|string| serde_json::from_str(&string))
-            .unwrap();
-
-        assert_eq!(init, deser)
+    /// Returns flags that are going to be automatically added by the compiler,
+    /// but were not explicitly requested by the user.
+    ///
+    /// Afterwards, the flags are used to prune JSON output before returning it.
+    pub fn selection_to_prune(&self) -> Self {
+        Self {
+            all: self.all.selection_to_prune(),
+            files: Default::default(),
+        }
     }
 
-    #[test]
-    fn all() {
-        let init = Selection {
-            all: Some(SolcStandardJsonInputSettingsSelectionFile::new_required()),
-            files: BTreeMap::new(),
-        };
-
-        let deser = serde_json::to_string(&init)
-            .and_then(|string| serde_json::from_str(&string))
-            .unwrap();
-
-        assert_eq!(init, deser)
-    }
-
-    #[test]
-    fn all_and_override() {
-        let init = Selection {
-            all: Some(SolcStandardJsonInputSettingsSelectionFile::new_required()),
-            files: BTreeMap::from([(
-                "Test".to_owned(),
-                SolcStandardJsonInputSettingsSelectionFile::new_required(),
-            )]),
-        };
-
-        let deser = serde_json::to_string(&init)
-            .and_then(|string| serde_json::from_str(&string))
-            .unwrap();
-
-        assert_eq!(init, deser)
+    /// Whether the flag is requested.
+    pub fn contains(&self, flag: &Flag) -> bool {
+        self.all.contains(flag)
     }
 }