Fix more memory leaks

Author: QuantumSegfault

crates/d/src/lib.rs

@@ -2638,7 +2638,7 @@ impl<'a, 'b> Bindgen for FunctionBindgen<'a, 'b> {
 
                 if matches!(self.r#gen.direction, Some(Direction::Import)) {
                     self.needs_deallocate = true;
-                    self.push_str(&format!("deallocate ~= {list};\n"));
+                    self.push_str(&format!("if ({list_src}.length) deallocate ~= {list};\n"));
                 }
 
                 self.push_str(&format!(
@@ -2671,12 +2671,17 @@ impl<'a, 'b> Bindgen for FunctionBindgen<'a, 'b> {
                 let len = tempname("_len", tmp);
 
                 self.push_str(&format!(
-                    "auto {ptr} = cast({elem_name}*)({});
-                    auto {len} = {};
+                    "auto {len} = {};
+                    auto {ptr} = {len} ? cast({elem_name}*)({}) : null;
                     ",
-                    operands[0], operands[1]
+                    operands[1], operands[0]
                 ));
 
+                if matches!(self.r#gen.direction, Some(Direction::Export)) {
+                    self.needs_deallocate = true;
+                    self.push_str(&format!("if ({len}) deallocate ~= cast(){ptr};\n"));
+                }
+
                 results.push(format!("{list_name}({ptr}[0..{len}])"));
             }
             abi::Instruction::StringLift => {
@@ -2686,12 +2691,17 @@ impl<'a, 'b> Bindgen for FunctionBindgen<'a, 'b> {
                 let len = tempname("_len", tmp);
 
                 self.push_str(&format!(
-                    "auto {ptr} = cast(char*)({});
-                    auto {len} = {};
+                    "auto {len} = {};
+                    auto {ptr} = {len} ? cast(char*)({}) : null;
                     ",
-                    operands[0], operands[1]
+                    operands[1], operands[0]
                 ));
 
+                if matches!(self.r#gen.direction, Some(Direction::Export)) {
+                    self.needs_deallocate = true;
+                    self.push_str(&format!("if ({len}) deallocate ~= cast(){ptr};\n"));
+                }
+
                 results.push(format!("WitString({ptr}[0..{len}])"));
             }
             abi::Instruction::ListLift { ty, element, .. } => {
@@ -2719,7 +2729,9 @@ impl<'a, 'b> Bindgen for FunctionBindgen<'a, 'b> {
 
                 if matches!(self.r#gen.direction, Some(Direction::Export)) {
                     self.needs_deallocate = true;
-                    self.push_str(&format!("deallocate ~= cast(void*){list}.ptr;\n"));
+                    self.push_str(&format!(
+                        "if ({list_len}) deallocate ~= cast(void*){list}.ptr;\n"
+                    ));
                 }
 
                 self.push_str(&format!(
@@ -2732,11 +2744,14 @@ impl<'a, 'b> Bindgen for FunctionBindgen<'a, 'b> {
                 self.push_str(&format!("{block_element} = {};", block_results[0]));
                 self.push_str("\n}\n");
 
-                if !matches!(self.r#gen.direction, Some(Direction::Export)) {
+                if matches!(self.r#gen.direction, Some(Direction::Import)) {
                     self.push_str(&format!(
                         "if ({list_len}) {}.free({list_src});\n",
                         self.r#gen.r#gen.common_module
                     ));
+                } else {
+                    self.needs_deallocate = true;
+                    self.push_str(&format!("if ({list_len}) deallocate ~= {list_src};\n"));
                 }
 
                 let list_name = self.r#gen.type_name(&Type::Id(*ty), self.r#gen.fqn);

crates/d/src/wit_common.d

@@ -499,7 +499,12 @@ struct DeallocateBuffer {
     }
 }
 
-version (CRuntime_WASI) {}
+version (CRuntime_WASI) {
+    version (WASIp1) {}
+    else version = LibcDefinesCABIRealloc;
+}
+
+version (LibcDefinesCABIRealloc) {}
 else
 @wasmExport!("cabi_realloc")
 void* cabi_realloc(void *ptr, size_t oldSize, size_t alignment, size_t newSize) {

crates/test/d-test-support/walloc.d

@@ -22,7 +22,7 @@ import ldc.intrinsics :
 extern(C) @nogc nothrow:
 
 /// MODIFIED FOR wit-bindgen TESTS
-enum MAX_ALLOCATIONS = 32;
+enum MAX_ALLOCATIONS = 2048;
 extern(D) void*[MAX_ALLOCATIONS] activePointers;
 extern(D) size_t[MAX_ALLOCATIONS] activeAllocSizes;