llvm-context: remove the linear memory pointer indirection (#211)

crates/llvm-context/src/polkavm/const/mod.rs

@@ -6,15 +6,9 @@ pub const LLVM_VERSION: semver::Version = semver::Version::new(18, 1, 4);
 /// The pointer width sized type.
 pub static XLEN: usize = revive_common::BIT_LENGTH_X32;
 
-/// The heap memory pointer pointer global variable name.
-pub static GLOBAL_HEAP_MEMORY_POINTER: &str = "memory_pointer";
-
 /// The calldata size global variable name.
 pub static GLOBAL_CALLDATA_SIZE: &str = "calldatasize";
 
-/// The call flags global variable name.
-pub static GLOBAL_CALL_FLAGS: &str = "call_flags";
-
 /// The deployer call header size that consists of:
 /// - bytecode hash (32 bytes)
 pub const DEPLOYER_CALL_HEADER_SIZE: usize = revive_common::BYTE_LENGTH_WORD;

crates/llvm-context/src/polkavm/context/function/runtime/entry.rs

@@ -24,22 +24,6 @@ impl Entry {
     where
         D: Dependency + Clone,
     {
-        context.set_global(
-            crate::polkavm::GLOBAL_HEAP_MEMORY_POINTER,
-            context.llvm().ptr_type(AddressSpace::Heap.into()),
-            AddressSpace::Stack,
-            context.xlen_type().get_undef(),
-        );
-        context.build_store(
-            context
-                .get_global(crate::polkavm::GLOBAL_HEAP_MEMORY_POINTER)?
-                .into(),
-            context.build_sbrk(
-                context.xlen_type().const_zero(),
-                context.xlen_type().const_zero(),
-            )?,
-        )?;
-
         context.set_global(
             crate::polkavm::GLOBAL_CALLDATA_SIZE,
             context.xlen_type(),
@@ -47,13 +31,6 @@ impl Entry {
             context.xlen_type().get_undef(),
         );
 
-        context.set_global(
-            crate::polkavm::GLOBAL_CALL_FLAGS,
-            context.word_type(),
-            AddressSpace::Stack,
-            context.word_const(0),
-        );
-
         Ok(())
     }
 
@@ -70,6 +47,11 @@ impl Entry {
             .build_runtime_call(revive_runtime_api::polkavm_imports::CALL_DATA_SIZE, &[])
             .expect("the call_data_size syscall method should return a value")
             .into_int_value();
+        let call_data_size_value = context.builder().build_int_truncate(
+            call_data_size_value,
+            context.xlen_type(),
+            "call_data_size_truncated",
+        )?;
         context
             .builder()
             .build_store(call_data_size_pointer, call_data_size_value)?;
@@ -90,13 +72,6 @@ impl Entry {
             .borrow()
             .get_nth_param(Self::ARGUMENT_INDEX_CALL_FLAGS);
 
-        context.set_global(
-            crate::polkavm::GLOBAL_CALL_FLAGS,
-            is_deploy.get_type(),
-            AddressSpace::Stack,
-            is_deploy.into_int_value(),
-        );
-
         let deploy_code_call_block = context.append_basic_block("deploy_code_call_block");
         let runtime_code_call_block = context.append_basic_block("runtime_code_call_block");
 

crates/llvm-context/src/polkavm/context/mod.rs

@@ -1209,17 +1209,17 @@ where
 
     /// Build a call to PolkaVM `msize` for querying the linear memory size.
     pub fn build_msize(&self) -> anyhow::Result<inkwell::values::IntValue<'ctx>> {
-        Ok(self
-            .builder()
-            .build_call(
-                self.runtime_api_method(revive_runtime_api::polkavm_imports::MEMORY_SIZE),
-                &[],
-                "call_msize",
-            )?
-            .try_as_basic_value()
-            .left()
-            .expect("sbrk returns an int")
-            .into_int_value())
+        let memory_size_pointer = self
+            .module()
+            .get_global(revive_runtime_api::polkavm_imports::MEMORY_SIZE)
+            .expect("the memory size symbol should have been declared")
+            .as_pointer_value();
+        let memory_size_value = self.builder().build_load(
+            self.xlen_type(),
+            memory_size_pointer,
+            "memory_size_value",
+        )?;
+        Ok(memory_size_value.into_int_value())
     }
 
     /// Call PolkaVM `sbrk` for extending the heap by `offset` + `size`,
@@ -1265,8 +1265,9 @@ where
         self.build_heap_alloc(offset, length)?;
 
         let heap_start = self
-            .get_global(crate::polkavm::GLOBAL_HEAP_MEMORY_POINTER)?
-            .value
+            .module()
+            .get_global(revive_runtime_api::polkavm_imports::MEMORY)
+            .expect("the memory symbol should have been declared")
             .as_pointer_value();
         Ok(self.build_gep(
             Pointer::new(self.byte_type(), AddressSpace::Stack, heap_start),