use wasi sdk 12 (#615)

* lucet-wasi-sdk: wasi sdk 12 no longer supports `--no-threads`

* dockerfile: use wasi-sdk 12

* ci: use wasi-sdk 12

* lucet-runtime: fix tests for wasi-sdk-12 by rewriting use_allocator.c in wat

use_allocator.c was a fixture used for tests that manipulated the size
of linear memory. written in C, it depended heavily on the implemention
of wasi-libc's allocator, which changed from sdk-11 to sdk-12. Rather
than try to depend on the new (still fragile) behavior these tests were
rewritten in pure wat, with a much simpler allocator behavior that just
expands the linear memory. The tests were modified to observe this new
behavior.

.circleci/config.yml

@@ -172,10 +172,10 @@ commands:
           name: "Install wasi-sdk"
           command: |
             set -x
-            curl -sS -L -O https://github.com/WebAssembly/wasi-sdk/releases/download/wasi-sdk-11/wasi-sdk-11.0-macos.tar.gz
-            tar xf wasi-sdk-11.0-macos.tar.gz
+            curl -sS -L -O https://github.com/WebAssembly/wasi-sdk/releases/download/wasi-sdk-12/wasi-sdk-12.0-macos.tar.gz
+            tar xf wasi-sdk-12.0-macos.tar.gz
             sudo mkdir -p /opt/wasi-sdk
-            sudo mv wasi-sdk-11.0/* /opt/wasi-sdk/
+            sudo mv wasi-sdk-12.0/* /opt/wasi-sdk/
       - run:
           name: "Make target: test-ci"
           command: |

.github/workflows/mac-ci.yml

@@ -18,10 +18,10 @@ jobs:
 
     - name: Install wasi-sdk (macos)
       run: |
-        curl -sS -L -O https://github.com/WebAssembly/wasi-sdk/releases/download/wasi-sdk-11/wasi-sdk-11.0-macos.tar.gz
-        tar xf wasi-sdk-11.0-macos.tar.gz
+        curl -sS -L -O https://github.com/WebAssembly/wasi-sdk/releases/download/wasi-sdk-12/wasi-sdk-12.0-macos.tar.gz
+        tar xf wasi-sdk-12.0-macos.tar.gz
         sudo mkdir -p /opt/wasi-sdk
-        sudo mv wasi-sdk-11.0/* /opt/wasi-sdk/
+        sudo mv wasi-sdk-12.0/* /opt/wasi-sdk/
 
     - name: Test Lucet
       run: make test-ci

Dockerfile

@@ -43,9 +43,9 @@ RUN rustup target add wasm32-wasi
 # Optional additional Rust programs
 RUN cargo install --debug rsign2 cargo-audit mdbook
 
-RUN curl -sSLO https://github.com/WebAssembly/wasi-sdk/releases/download/wasi-sdk-11/wasi-sdk_11.0_amd64_ubuntu20.04.deb \
-    && dpkg -i wasi-sdk_11.0_amd64_ubuntu20.04.deb \
-    && rm -f wasi-sdk_11.0_amd64_ubuntu20.04.deb
+RUN curl -sSLO https://github.com/WebAssembly/wasi-sdk/releases/download/wasi-sdk-12/wasi-sdk_12.0_amd64.deb \
+    && dpkg -i wasi-sdk_12.0_amd64.deb \
+    && rm -f wasi-sdk_12.0_amd64.deb
 
 ENV WASI_SDK=/opt/wasi-sdk
 

lucet-runtime/lucet-runtime-tests/guests/entrypoint/use_allocator.wat

@@ -0,0 +1,50 @@
+(module
+  (memory 1)
+  ;; Expand the wasm heap and initialize it to a value.
+  ;; sets out-pointer to -1 if heap expansion fails.
+  ;; Parameters are:
+  ;;   0. initialization value (byte)
+  ;;   1. size (in wasm pages)
+  ;;   2. out-pointer to store start address of expanded heap
+  ;;  Locals are:
+  ;;   3. expanded heap start page
+  (func $expand_and_memset (export "expand_and_memset") (param i32 i32 i32)
+    (local i32)
+    (local.set 3 (memory.grow (local.get 1)))
+    (if (i32.eq (local.get 3) (i32.const -1))
+        (then (i32.store (local.get 2) (i32.const -1)))
+        (else
+            (i32.store (local.get 2) (i32.mul (local.get 3) (i32.const 65536)))
+            (call $memset (i32.load (local.get 2)) (local.get 0) (i32.mul (local.get 1) (i32.const 65536)))
+        )
+    )
+  )
+
+
+  ;; memset
+  ;; parameters are
+  ;;   0. pointer to start of region
+  ;;   1. constant value (byte)
+  ;;   2. size of region, in bytes
+  ;; locals are
+  ;;   3. current pointer
+  (func $memset (export "memset") (param i32 i32 i32)
+    (local i32)
+    (local.set 3 (local.get 0))
+    (loop
+     (i32.store8 (local.get 3) (local.get 1))
+     (local.set 3 (i32.add (local.get 3) (i32.const 1)))
+     (br_if 0 (i32.lt_u (local.get 3) (i32.add (local.get 0) (local.get 2))))
+    )
+  )
+
+  ;; increment_ptr
+  ;; increment the byte at the pointer
+  ;; parameters are
+  ;;  0. pointer to byte
+  (func $increment_ptr (export "increment_ptr") (param i32)
+    (i32.store8 (local.get 0)
+                (i32.add (i32.const 1) (i32.load (local.get 0))))
+  )
+
+)

lucet-runtime/lucet-runtime-tests/src/build.rs

@@ -31,8 +31,7 @@ where
     let workdir = TempDir::new().expect("create working directory");
 
     let wasm_build = Link::new(&[c_file])
-        .with_cflag("-nostartfiles")
-        .with_link_opt(LinkOpt::NoDefaultEntryPoint)
+        .with_cflag("-mexec-model=reactor")
         .with_link_opt(LinkOpt::AllowUndefinedAll)
         .with_link_opt(LinkOpt::ExportAll);