1 files changed, 167 insertions, 0 deletions
diff --git a/src/librustc_trans/trans/value.rs b/src/librustc_trans/trans/value.rs
new file mode 100644
index 00000000000..8d74275c92a
--- /dev/null
+++ b/src/librustc_trans/trans/value.rs
@@ -0,0 +1,167 @@
+// Copyright 2013 The Rust Project Developers. See the COPYRIGHT
+// file at the top-level directory of this distribution and at
+// http://rust-lang.org/COPYRIGHT.
+//
+// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
+// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
+// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
+// option. This file may not be copied, modified, or distributed
+// except according to those terms.
+
+use llvm;
+use llvm::{UseRef, ValueRef};
+use trans::basic_block::BasicBlock;
+use trans::common::Block;
+use libc::c_uint;
+
+pub struct Value(pub ValueRef);
+
+macro_rules! opt_val ( ($e:expr) => (
+    unsafe {
+        match $e {
+            p if p.is_not_null() => Some(Value(p)),
+            _ => None
+        }
+    }
+))
+
+/**
+ * Wrapper for LLVM ValueRef
+ */
+impl Value {
+    /// Returns the native ValueRef
+    pub fn get(&self) -> ValueRef {
+        let Value(v) = *self; v
+    }
+
+    /// Returns the BasicBlock that contains this value
+    pub fn get_parent(self) -> Option<BasicBlock> {
+        unsafe {
+            match llvm::LLVMGetInstructionParent(self.get()) {
+                p if p.is_not_null() => Some(BasicBlock(p)),
+                _ => None
+            }
+        }
+    }
+
+    /// Removes this value from its containing BasicBlock
+    pub fn erase_from_parent(self) {
+        unsafe {
+            llvm::LLVMInstructionEraseFromParent(self.get());
+        }
+    }
+
+    /// Returns the single dominating store to this value, if any
+    /// This only performs a search for a trivially dominating store. The store
+    /// must be the only user of this value, and there must not be any conditional
+    /// branches between the store and the given block.
+    pub fn get_dominating_store(self, bcx: Block) -> Option<Value> {
+        match self.get_single_user().and_then(|user| user.as_store_inst()) {
+            Some(store) => {
+                store.get_parent().and_then(|store_bb| {
+                    let mut bb = BasicBlock(bcx.llbb);
+                    let mut ret = Some(store);
+                    while bb.get() != store_bb.get() {
+                        match bb.get_single_predecessor() {
+                            Some(pred) => bb = pred,
+                            None => { ret = None; break }
+                        }
+                    }
+                    ret
+                })
+            }
+            _ => None
+        }
+    }
+
+    /// Returns the first use of this value, if any
+    pub fn get_first_use(self) -> Option<Use> {
+        unsafe {
+            match llvm::LLVMGetFirstUse(self.get()) {
+                u if u.is_not_null() => Some(Use(u)),
+                _ => None
+            }
+        }
+    }
+
+    /// Tests if there are no uses of this value
+    pub fn has_no_uses(self) -> bool {
+        self.get_first_use().is_none()
+    }
+
+    /// Returns the single user of this value
+    /// If there are no users or multiple users, this returns None
+    pub fn get_single_user(self) -> Option<Value> {
+        let mut iter = self.user_iter();
+        match (iter.next(), iter.next()) {
+            (Some(first), None) => Some(first),
+            _ => None
+        }
+    }
+
+    /// Returns an iterator for the users of this value
+    pub fn user_iter(self) -> Users {
+        Users {
+            next: self.get_first_use()
+        }
+    }
+
+    /// Returns the requested operand of this instruction
+    /// Returns None, if there's no operand at the given index
+    pub fn get_operand(self, i: uint) -> Option<Value> {
+        opt_val!(llvm::LLVMGetOperand(self.get(), i as c_uint))
+    }
+
+    /// Returns the Store represent by this value, if any
+    pub fn as_store_inst(self) -> Option<Value> {
+        opt_val!(llvm::LLVMIsAStoreInst(self.get()))
+    }
+
+    /// Tests if this value is a terminator instruction
+    pub fn is_a_terminator_inst(self) -> bool {
+        unsafe {
+            llvm::LLVMIsATerminatorInst(self.get()).is_not_null()
+        }
+    }
+}
+
+pub struct Use(UseRef);
+
+/**
+ * Wrapper for LLVM UseRef
+ */
+impl Use {
+    pub fn get(&self) -> UseRef {
+        let Use(v) = *self; v
+    }
+
+    pub fn get_user(self) -> Value {
+        unsafe {
+            Value(llvm::LLVMGetUser(self.get()))
+        }
+    }
+
+    pub fn get_next_use(self) -> Option<Use> {
+        unsafe {
+            match llvm::LLVMGetNextUse(self.get()) {
+                u if u.is_not_null() => Some(Use(u)),
+                _ => None
+            }
+        }
+    }
+}
+
+/// Iterator for the users of a value
+pub struct Users {
+    next: Option<Use>
+}
+
+impl Iterator<Value> for Users {
+    fn next(&mut self) -> Option<Value> {
+        let current = self.next;
+
+        self.next = current.and_then(|u| u.get_next_use());
+
+        current.map(|u| u.get_user())
+    }
+}