Check that the instruction has an alignment to be queried or set.

Author: nlewycky

src/values/instruction_value.rs

@@ -1,5 +1,5 @@
 use either::{Either, Either::{Left, Right}};
-use llvm_sys::core::{LLVMGetAlignment, LLVMSetAlignment, LLVMGetInstructionOpcode, LLVMIsTailCall, LLVMGetPreviousInstruction, LLVMGetNextInstruction, LLVMGetInstructionParent, LLVMInstructionEraseFromParent, LLVMInstructionClone, LLVMSetVolatile, LLVMGetVolatile, LLVMGetNumOperands, LLVMGetOperand, LLVMGetOperandUse, LLVMSetOperand, LLVMValueAsBasicBlock, LLVMIsABasicBlock, LLVMGetICmpPredicate, LLVMGetFCmpPredicate};
+use llvm_sys::core::{LLVMGetAlignment, LLVMSetAlignment, LLVMGetInstructionOpcode, LLVMIsTailCall, LLVMGetPreviousInstruction, LLVMGetNextInstruction, LLVMGetInstructionParent, LLVMInstructionEraseFromParent, LLVMInstructionClone, LLVMSetVolatile, LLVMGetVolatile, LLVMGetNumOperands, LLVMGetOperand, LLVMGetOperandUse, LLVMSetOperand, LLVMValueAsBasicBlock, LLVMIsABasicBlock, LLVMGetICmpPredicate, LLVMGetFCmpPredicate, LLVMIsAAllocaInst, LLVMIsALoadInst, LLVMIsAStoreInst};
 #[llvm_versions(3.9..=latest)]
 use llvm_sys::core::LLVMInstructionRemoveFromParent;
 use llvm_sys::LLVMOpcode;
@@ -200,9 +200,15 @@ impl InstructionValue {
 
     // SubTypes: Only apply to memory access and alloca instructions
     /// Returns alignment on a memory access instruction or alloca.
-    pub fn get_alignment(&self) -> u32 {
+    pub fn get_alignment(&self) -> Result<u32, &'static str> {
+        let value_ref = self.as_value_ref();
         unsafe {
-            LLVMGetAlignment(self.as_value_ref())
+            if LLVMIsAAllocaInst(value_ref).is_null() &&
+                LLVMIsALoadInst(value_ref).is_null() &&
+                LLVMIsAStoreInst(value_ref).is_null() {
+                return Err("Value is not an alloca, load or store.");
+            }
+            Ok(LLVMGetAlignment(value_ref))
         }
     }
 
@@ -212,8 +218,14 @@ impl InstructionValue {
         if !alignment.is_power_of_two() && alignment != 0 {
             return Err("Alignment is not a power of 2!");
         }
+        let value_ref = self.as_value_ref();
         unsafe {
-            Ok(LLVMSetAlignment(self.as_value_ref(), alignment))
+            if LLVMIsAAllocaInst(value_ref).is_null() &&
+                LLVMIsALoadInst(value_ref).is_null() &&
+                LLVMIsAStoreInst(value_ref).is_null() {
+                return Err("Value is not an alloca, load or store.");
+            }
+            Ok(LLVMSetAlignment(value_ref, alignment))
         }
     }
 

tests/all/test_instruction_values.rs

@@ -276,7 +276,8 @@ fn test_mem_instructions() {
     let f32_val = f32_type.const_float(::std::f64::consts::PI);
 
     let store_instruction = builder.build_store(arg1, f32_val);
-    let load_instruction = builder.build_load(arg1, "").as_instruction_value().unwrap();
+    let load = builder.build_load(arg1, "");
+    let load_instruction = load.as_instruction_value().unwrap();
 
     assert_eq!(store_instruction.get_volatile(), false);
     assert_eq!(load_instruction.get_volatile(), false);
@@ -289,17 +290,21 @@ fn test_mem_instructions() {
     assert_eq!(store_instruction.get_volatile(), false);
     assert_eq!(load_instruction.get_volatile(), false);
 
-    assert_eq!(store_instruction.get_alignment(), 0);
-    assert_eq!(load_instruction.get_alignment(), 0);
+    assert_eq!(store_instruction.get_alignment().unwrap(), 0);
+    assert_eq!(load_instruction.get_alignment().unwrap(), 0);
     assert!(store_instruction.set_alignment(16).is_ok());
     assert!(load_instruction.set_alignment(16).is_ok());
-    assert_eq!(store_instruction.get_alignment(), 16);
-    assert_eq!(load_instruction.get_alignment(), 16);
+    assert_eq!(store_instruction.get_alignment().unwrap(), 16);
+    assert_eq!(load_instruction.get_alignment().unwrap(), 16);
     assert!(store_instruction.set_alignment(0).is_ok());
     assert!(load_instruction.set_alignment(0).is_ok());
-    assert_eq!(store_instruction.get_alignment(), 0);
-    assert_eq!(load_instruction.get_alignment(), 0);
+    assert_eq!(store_instruction.get_alignment().unwrap(), 0);
+    assert_eq!(load_instruction.get_alignment().unwrap(), 0);
 
     assert!(store_instruction.set_alignment(14).is_err());
-    assert_eq!(store_instruction.get_alignment(), 0);
+    assert_eq!(store_instruction.get_alignment().unwrap(), 0);
+
+    let fadd_instruction = builder.build_float_add(load.into_float_value(), f32_val, "").as_instruction_value().unwrap();
+    assert!(fadd_instruction.get_alignment().is_err());
+    assert!(fadd_instruction.set_alignment(16).is_err());
 }