allow configuration of the PVM stack size

Signed-off-by: xermicus <cyrill@parity.io>

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

@@ -119,6 +119,9 @@ where
     /// The loop stack default capacity.
     const LOOP_STACK_INITIAL_CAPACITY: usize = 16;
 
+    /// The PolkaVM minimum stack size.
+    const POLKAVM_STACK_SIZE: u32 = 0x4000;
+
     /// Link in the stdlib module.
     fn link_stdlib_module(
         llvm: &'ctx inkwell::context::Context,
@@ -161,6 +164,21 @@ where
         }
     }
 
+    /// Configure the PolkaVM minimum stack size.
+    fn set_polkavm_stack_size(
+        llvm: &'ctx inkwell::context::Context,
+        module: &inkwell::module::Module<'ctx>,
+        size: u32,
+    ) {
+        module
+            .link_in_module(pallet_contracts_pvm_llapi::min_stack_size(
+                llvm,
+                "polkavm_stack_size",
+                size,
+            ))
+            .expect("the PolkaVM minimum stack size module should be linkable");
+    }
+
     /// PolkaVM wants PIE code; we set this flag on the module here.
     fn set_module_flags(
         llvm: &'ctx inkwell::context::Context,
@@ -186,6 +204,7 @@ where
     ) -> Self {
         Self::link_stdlib_module(llvm, &module);
         Self::link_polkavm_guest_module(llvm, &module);
+        Self::set_polkavm_stack_size(llvm, &module, Self::POLKAVM_STACK_SIZE);
         Self::set_module_flags(llvm, &module);
 
         let intrinsics = Intrinsics::new(llvm, &module);

crates/pallet-contracts-pvm-llapi/src/lib.rs

@@ -28,6 +28,21 @@ pub fn module<'context>(
     Module::parse_bitcode_from_buffer(&buf, context)
 }
 
+/// Creates a module that sets the PolkaVM minimum stack size to [`size`] if linked in.
+pub fn min_stack_size<'context>(
+    context: &'context Context,
+    module_name: &str,
+    size: u32,
+) -> Module<'context> {
+    let module = context.create_module(module_name);
+    module.set_inline_assembly(&format!(
+        ".pushsection .polkavm_min_stack_size,\"\",@progbits
+        .word {size}
+        .popsection"
+    ));
+    module
+}
+
 #[cfg(test)]
 mod tests {
     #[test]