fix: memory operations should be unaligned (#67)

paradigmxyz · Dec 4, 2024 · 0d138b6 · 0d138b6
1 parent c3e2a3c
commit 0d138b6
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Showing 4 changed files with 30 additions and 12 deletions.
diff --git a/crates/revmc-backend/src/traits.rs b/crates/revmc-backend/src/traits.rs
@@ -271,8 +271,14 @@ pub trait Builder: BackendTypes + TypeMethods {
     fn stack_store(&mut self, value: Self::Value, slot: Self::StackSlot);
     fn stack_addr(&mut self, ty: Self::Type, slot: Self::StackSlot) -> Self::Value;
 
-    fn load(&mut self, ty: Self::Type, ptr: Self::Value, name: &str) -> Self::Value;
-    fn store(&mut self, value: Self::Value, ptr: Self::Value);
+    fn load(&mut self, ty: Self::Type, ptr: Self::Value, name: &str) -> Self::Value {
+        self.load_unaligned(ty, ptr, name)
+    }
+    fn load_unaligned(&mut self, ty: Self::Type, ptr: Self::Value, name: &str) -> Self::Value;
+    fn store(&mut self, value: Self::Value, ptr: Self::Value) {
+        self.store_unaligned(value, ptr);
+    }
+    fn store_unaligned(&mut self, value: Self::Value, ptr: Self::Value);
 
     fn nop(&mut self);
     fn ret(&mut self, values: &[Self::Value]);

diff --git a/crates/revmc-cranelift/src/lib.rs b/crates/revmc-cranelift/src/lib.rs
@@ -465,10 +465,19 @@ impl<'a> Builder for EvmCraneliftBuilder<'a> {
         self.bcx.ins().load(ty, MemFlags::trusted(), ptr, 0)
     }
 
+    fn load_unaligned(&mut self, ty: Self::Type, ptr: Self::Value, name: &str) -> Self::Value {
+        let _ = name;
+        self.bcx.ins().load(ty, MemFlags::new().with_notrap(), ptr, 0)
+    }
+
     fn store(&mut self, value: Self::Value, ptr: Self::Value) {
         self.bcx.ins().store(MemFlags::trusted(), value, ptr, 0);
     }
 
+    fn store_unaligned(&mut self, value: Self::Value, ptr: Self::Value) {
+        self.bcx.ins().store(MemFlags::new().with_notrap(), value, ptr, 0);
+    }
+
     fn nop(&mut self) {
         self.bcx.ins().nop();
     }

diff --git a/crates/revmc-llvm/src/lib.rs b/crates/revmc-llvm/src/lib.rs
@@ -703,10 +703,21 @@ impl Builder for EvmLlvmBuilder<'_, '_> {
         self.bcx.build_load(ty, ptr.into_pointer_value(), name).unwrap()
     }
 
+    fn load_unaligned(&mut self, ty: Self::Type, ptr: Self::Value, name: &str) -> Self::Value {
+        let value = self.load(ty, ptr, name);
+        self.current_block().unwrap().get_last_instruction().unwrap().set_alignment(1).unwrap();
+        value
+    }
+
     fn store(&mut self, value: Self::Value, ptr: Self::Value) {
         self.bcx.build_store(ptr.into_pointer_value(), value).unwrap();
     }
 
+    fn store_unaligned(&mut self, value: Self::Value, ptr: Self::Value) {
+        let inst = self.bcx.build_store(ptr.into_pointer_value(), value).unwrap();
+        inst.set_alignment(1).unwrap();
+    }
+
     fn nop(&mut self) {
         // LLVM doesn't have a NOP instruction.
     }

diff --git a/crates/revmc/src/compiler/translate.rs b/crates/revmc/src/compiler/translate.rs
@@ -1945,14 +1945,6 @@ impl<B: Backend> FunctionCx<'_, B> {
     /// - `Store8` => `fn mstore(offset: u256, value: u8, ecx: ptr) -> InstructionResult`
     fn build_mem_op(&mut self, kind: MemOpKind) {
         let is_load = matches!(kind, MemOpKind::Load);
-        // TODO: If `store` is inlined it can cause segfaults. https://github.com/paradigmxyz/revmc/issues/61
-        if !is_load {
-            self.bcx.add_function_attribute(
-                None,
-                Attribute::NoInline,
-                FunctionAttributeLocation::Function,
-            );
-        }
         let ptr_args = if is_load { &[1, 2][..] } else { &[2][..] };
         for &ptr_arg in ptr_args {
             for attr in default_attrs::for_ref() {
@@ -2046,7 +2038,7 @@ impl<B: Backend> FunctionCx<'_, B> {
         let slot = self.bcx.gep(self.i8_type, buffer_ptr, &[offset], "slot");
         match kind {
             MemOpKind::Load => {
-                let loaded = self.bcx.load(self.word_type, slot, "slot.value");
+                let loaded = self.bcx.load_unaligned(self.word_type, slot, "slot.value");
                 let loaded =
                     if cfg!(target_endian = "little") { self.bcx.bswap(loaded) } else { loaded };
                 self.bcx.store(loaded, value);
@@ -2057,7 +2049,7 @@ impl<B: Backend> FunctionCx<'_, B> {
                 } else {
                     value
                 };
-                self.bcx.store(value, slot);
+                self.bcx.store_unaligned(value, slot);
             }
         }