Merge pull request rust-lang#125 from wasmerio/constantint

Add IntValue::is_constant_int() which is true iff is_const() and the int value is not a constant expression.

src/values/int_value.rs

@@ -1,4 +1,4 @@
-use llvm_sys::core::{LLVMConstNot, LLVMConstNeg, LLVMConstNSWNeg, LLVMConstNUWNeg, LLVMConstAdd, LLVMConstNSWAdd, LLVMConstNUWAdd, LLVMConstSub, LLVMConstNSWSub, LLVMConstNUWSub, LLVMConstMul, LLVMConstNSWMul, LLVMConstNUWMul, LLVMConstUDiv, LLVMConstSDiv, LLVMConstSRem, LLVMConstURem, LLVMConstIntCast, LLVMConstXor, LLVMConstOr, LLVMConstAnd, LLVMConstExactSDiv, LLVMConstShl, LLVMConstLShr, LLVMConstAShr, LLVMConstUIToFP, LLVMConstSIToFP, LLVMConstIntToPtr, LLVMConstTrunc, LLVMConstSExt, LLVMConstZExt, LLVMConstTruncOrBitCast, LLVMConstSExtOrBitCast, LLVMConstZExtOrBitCast, LLVMConstBitCast, LLVMConstICmp, LLVMConstIntGetZExtValue, LLVMConstIntGetSExtValue, LLVMConstSelect};
+use llvm_sys::core::{LLVMConstNot, LLVMConstNeg, LLVMConstNSWNeg, LLVMConstNUWNeg, LLVMConstAdd, LLVMConstNSWAdd, LLVMConstNUWAdd, LLVMConstSub, LLVMConstNSWSub, LLVMConstNUWSub, LLVMConstMul, LLVMConstNSWMul, LLVMConstNUWMul, LLVMConstUDiv, LLVMConstSDiv, LLVMConstSRem, LLVMConstURem, LLVMConstIntCast, LLVMConstXor, LLVMConstOr, LLVMConstAnd, LLVMConstExactSDiv, LLVMConstShl, LLVMConstLShr, LLVMConstAShr, LLVMConstUIToFP, LLVMConstSIToFP, LLVMConstIntToPtr, LLVMConstTrunc, LLVMConstSExt, LLVMConstZExt, LLVMConstTruncOrBitCast, LLVMConstSExtOrBitCast, LLVMConstZExtOrBitCast, LLVMConstBitCast, LLVMConstICmp, LLVMConstIntGetZExtValue, LLVMConstIntGetSExtValue, LLVMConstSelect, LLVMIsAConstantInt};
 #[llvm_versions(4.0..=latest)]
 use llvm_sys::core::LLVMConstExactUDiv;
 use llvm_sys::prelude::LLVMValueRef;
@@ -385,7 +385,10 @@ impl IntValue {
         BasicValueEnum::new(value)
     }
 
-    /// Determines whether or not an `IntValue` is a constant.
+    /// Determines whether or not an `IntValue` is an `llvm::Constant`.
+    ///
+    /// Constants includes values that are not known at compile time, for
+    /// example the address of a function casted to an integer.
     ///
     /// # Example
     ///
@@ -402,6 +405,25 @@ impl IntValue {
         self.int_value.is_const()
     }
 
+    /// Determines whether or not an `IntValue` is an `llvm::ConstantInt`.
+    ///
+    /// ConstantInt only includes values that are known at compile time.
+    ///
+    /// # Example
+    ///
+    /// ```no_run
+    /// use inkwell::context::Context;
+    ///
+    /// let context = Context::create();
+    /// let i64_type = context.i64_type();
+    /// let i64_val = i64_type.const_int(12, false);
+    ///
+    /// assert!(i64_val.is_constant_int());
+    /// ```
+    pub fn is_constant_int(&self) -> bool {
+        !unsafe { LLVMIsAConstantInt(self.as_value_ref()) }.is_null()
+    }
+
     /// Obtains a constant `IntValue`'s zero extended value.
     ///
     /// # Example
@@ -417,7 +439,7 @@ impl IntValue {
     /// ```
     pub fn get_zero_extended_constant(&self) -> Option<u64> {
         // Garbage values are produced on non constant values
-        if !self.is_const() {
+        if !self.is_constant_int() {
             return None;
         }
         if self.get_type().get_bit_width() > 64 {
@@ -444,7 +466,7 @@ impl IntValue {
     /// ```
     pub fn get_sign_extended_constant(&self) -> Option<i64> {
         // Garbage values are produced on non constant values
-        if !self.is_const() {
+        if !self.is_constant_int() {
             return None;
         }
         if self.get_type().get_bit_width() > 64 {

tests/all/test_values.rs

@@ -1251,3 +1251,20 @@ fn test_aggregate_returns() {
 
     assert!(module.verify().is_ok());
 }
+
+#[test]
+fn test_constant_expression() {
+    let context = Context::create();
+    let builder = context.create_builder();
+    let module = context.create_module("my_mod");
+
+    let i32_type = context.i32_type();
+    let void_type = context.void_type();
+    let fn_type = void_type.fn_type(&[], false);
+
+    let function = module.add_function("", fn_type, None);
+    let expr = builder.build_ptr_to_int(function.as_global_value().as_pointer_value(), i32_type, "");
+
+    assert!(expr.is_const());
+    assert!(!expr.is_constant_int());
+}