Initial RISC-V support (#1718)

* Fix message dispatch for riscv

* Fix error handlers for riscv

* Fix allocator for riscv

* Fix ext for riscv

* Remove not needed manifest keys (they are already removed from the template)

* Add no_main to all examples

* Fix CI

* Fix multisig doc test

* Update linking to latest supported toolchain

* fmt

* fmt

* fmt

* Fix mess caused by rustfmt

* Combine no_std and no_main

* Update .gitlab-ci.yml

Co-authored-by: Andrew Jones <ascjones@gmail.com>

* Remove not needed block

---------

Co-authored-by: Andrew Jones <ascjones@gmail.com>

.gitlab-ci.yml

@@ -39,10 +39,12 @@ variables:
   # this fix not yet in stable: https://github.com/rust-lang/rust-clippy/issues/8895.
   # Remove the following line again as soon as `clippy` on stable succeeds again.
   CLIPPY_ALLOWED:                  "clippy::extra_unused_lifetimes"
-  # This is a target that does not have a standard library in contrast to Wasm. We compile against
-  # this target to make sure that we don't pull in `std` by accident (through dependencies).
-  # See https://doc.rust-lang.org/nightly/rustc/platform-support.html#tier-2.
-  NO_STD_TARGET:                   "aarch64-unknown-none"
+  # We plan to fully support RISC-V as a bytecode for contracts soon.
+  # RISC-V does not have a standard library in contrast to Wasm. Compiling against
+  # this target also makes sure that we don't pull in `std` by accident (through dependencies).
+  # RISC-V is a modular archtitecture. We might switch to a different flavor with more features
+  # later. For example, `riscv32imc-unknown-none-elf`.
+  RISCV_TARGET:                   "riscv32i-unknown-none-elf"
 
 workflow:
   rules:
@@ -209,16 +211,15 @@ check-wasm:
         cargo check --verbose --no-default-features --target wasm32-unknown-unknown --manifest-path ./crates/${crate}/Cargo.toml;
       done
 
-# We just check on a target which doesn't have `std` to make sure that we don't pull in `std` by accident
-check-no-std:
+check-riscv:
   stage:                           check
   <<:                              *docker-env
   <<:                              *test-refs
   variables:
     RUSTC_BOOTSTRAP:               "1"
   script:
     - for crate in ${ALSO_WASM_CRATES}; do
-        cargo check --verbose --no-default-features --target $NO_STD_TARGET -Zbuild-std="core,alloc" --manifest-path ./crates/${crate}/Cargo.toml;
+        cargo check --verbose --no-default-features --target $RISCV_TARGET -Zbuild-std="core,alloc" --manifest-path ./crates/${crate}/Cargo.toml;
       done
 
 dylint:
@@ -426,8 +427,8 @@ examples-contract-build:
       done
     - cargo +stable contract build --manifest-path ./integration-tests/set_code_hash/updated_incrementer/Cargo.toml
 
-# We only check a few basic contracts here, no need to check them all.
-examples-no-std-check:
+# TODO: Use cargo contract as soon as it has RISC-V support
+examples-contract-build-riscv:
   stage:                           examples
   <<:                              *docker-env
   <<:                              *test-refs
@@ -442,15 +443,15 @@ examples-no-std-check:
     #  - upgradeable-contracts
     # This uses dlmalloc which is only supported on select targets.
     #   - custom_allocator
-    # Pulls in sp-std which needlessly requires atomic pointers.
+    # Pulls in sp-std which needlessly requires atomic pointers (TODO: Fix sp-std and enable this example)
     #   - call-runtime
     - for example in integration-tests/*/; do
         if [ "$example" = "integration-tests/lang-err-integration-tests/" ]; then continue; fi;
         if [ "$example" = "integration-tests/upgradeable-contracts/" ]; then continue; fi;
         if [ "$example" = "integration-tests/custom_allocator/" ]; then continue; fi;
         if [ "$example" = "integration-tests/call-runtime/" ]; then continue; fi;
         pushd $example &&
-        cargo +stable check --no-default-features --target $NO_STD_TARGET -Zbuild-std="core,alloc" &&
+        cargo +stable build --no-default-features --target $RISCV_TARGET -Zbuild-std="core,alloc" &&
         popd;
       done
 

crates/allocator/src/bump.rs

@@ -68,13 +68,21 @@ struct InnerAlloc {
 impl InnerAlloc {
     const fn new() -> Self {
         Self {
-            next: 0,
-            upper_limit: 0,
+            next: Self::heap_start(),
+            upper_limit: Self::heap_end(),
         }
     }
 
     cfg_if::cfg_if! {
         if #[cfg(test)] {
+            const fn heap_start() -> usize {
+                0
+            }
+
+            const fn heap_end() -> usize {
+                0
+            }
+
             /// Request a `pages` number of page sized sections of Wasm memory. Each page is `64KiB` in size.
             ///
             /// Returns `None` if a page is not available.
@@ -85,13 +93,29 @@ impl InnerAlloc {
                 Some(self.upper_limit)
             }
         } else if #[cfg(feature = "std")] {
+            const fn heap_start() -> usize {
+                0
+            }
+
+            const fn heap_end() -> usize {
+                0
+            }
+
             fn request_pages(&mut self, _pages: usize) -> Option<usize> {
                 unreachable!(
                     "This branch is only used to keep the compiler happy when building tests, and
                      should never actually be called outside of a test run."
                 )
             }
         } else if #[cfg(target_arch = "wasm32")] {
+            const fn heap_start() -> usize {
+                0
+            }
+
+            const fn heap_end() -> usize {
+                0
+            }
+
             /// Request a `pages` number of pages of Wasm memory. Each page is `64KiB` in size.
             ///
             /// Returns `None` if a page is not available.
@@ -103,11 +127,24 @@ impl InnerAlloc {
 
                 prev_page.checked_mul(PAGE_SIZE)
             }
-        } else {
-            /// On other architectures growing memory probably doesn't make sense.
+        } else if #[cfg(target_arch = "riscv32")] {
+            const fn heap_start() -> usize {
+                // Placeholder value until we specified our riscv VM
+                0x7000_0000
+            }
+
+            const fn heap_end() -> usize {
+                // Placeholder value until we specified our riscv VM
+                // Let's just assume a cool megabyte of mem for now
+                0x7000_0400
+            }
+
             fn request_pages(&mut self, _pages: usize) -> Option<usize> {
+                // On riscv the memory can't be grown
                 None
             }
+        } else {
+            core::compile_error!("ink! only supports wasm32 and riscv32");
         }
     }
 

crates/allocator/src/lib.rs

@@ -23,17 +23,13 @@
     html_favicon_url = "https://use.ink/crate-docs/favicon.png"
 )]
 #![cfg_attr(not(feature = "std"), no_std)]
-#![cfg_attr(not(feature = "std"), feature(alloc_error_handler))]
 
 #[cfg(not(any(feature = "std", feature = "no-allocator")))]
 #[global_allocator]
 static mut ALLOC: bump::BumpAllocator = bump::BumpAllocator {};
 
 mod bump;
 
-#[cfg(not(feature = "std"))]
-mod handlers;
-
 #[cfg(all(test, feature = "std", feature = "ink-fuzz-tests",))]
 #[macro_use(quickcheck)]
 extern crate quickcheck_macros;

crates/env/Cargo.toml

@@ -3,6 +3,7 @@ name = "ink_env"
 version = "4.1.0"
 authors = ["Parity Technologies <admin@parity.io>", "Robin Freyler <robin@parity.io>"]
 edition = "2021"
+rust-version = "1.68"
 
 license = "Apache-2.0"
 readme = "README.md"