feat: add WAMR WebAssembly engine support for Halide JIT

Author: soldair

doc/BuildingHalideWithCMake.md

@@ -150,6 +150,7 @@ building the core pieces of Halide.
 | [flatbuffers] | `~=23.5.26`        | `WITH_SERIALIZATION=ON`    |                                                     |
 | [wabt]        | `==1.0.39`         | `Halide_WASM_BACKEND=wabt` | Does not have a stable API; exact version required. |
 | [V8]          | trunk              | `Halide_WASM_BACKEND=V8`   | Difficult to build. See [WebAssembly.md]            |
+| [WAMR]        | `>=2.4.3`          | `Halide_WASM_BACKEND=WAMR` | Built natively as static library from source.      |
 | [Python]      | `>=3.10`           | `WITH_PYTHON_BINDINGS=ON`  |                                                     |
 | [pybind11]    | `~=2.11.1`         | `WITH_PYTHON_BINDINGS=ON`  |                                                     |
 
@@ -456,7 +457,7 @@ The following option selects the execution engine for in-process WASM testing:
 
 | Option                | Default | Description                                                                              |
 | --------------------- | ------- | ---------------------------------------------------------------------------------------- |
-| `Halide_WASM_BACKEND` | `wabt`  | Select the backend for WASM testing. Can be `wabt`, `V8` or a false value such as `OFF`. |
+| `Halide_WASM_BACKEND` | `wabt`  | Select the backend for WASM testing. Can be `wabt`, `V8`, `WAMR` or a false value such as `OFF`. |
 
 ## Installing
 

src/CMakeLists.txt

@@ -580,7 +580,7 @@ target_compile_definitions(Halide PUBLIC
 
 set(Halide_WASM_BACKEND "wabt"
     CACHE STRING "Which backend to use for Halide's WASM testing.")
-set_property(CACHE Halide_WASM_BACKEND PROPERTY STRINGS "wabt;V8;OFF")
+set_property(CACHE Halide_WASM_BACKEND PROPERTY STRINGS "wabt;V8;WAMR;OFF")
 
 if (MSVC AND Halide_WASM_BACKEND STREQUAL "wabt")
     message(WARNING "wabt is not yet supported on Windows")
@@ -598,6 +598,31 @@ elseif (Halide_WASM_BACKEND STREQUAL "V8")
     _Halide_pkgdep(V8)
     target_compile_definitions(Halide PRIVATE WITH_V8)
     target_link_libraries(Halide PRIVATE V8::V8)
+elseif (Halide_WASM_BACKEND STREQUAL "WAMR")
+    set(Halide_WAMR_ROOT_DIR "" CACHE PATH "Path to root directory of WAMR repository sources")
+
+    if ("${Halide_WAMR_ROOT_DIR}" STREQUAL "")
+        if (EXISTS "${CMAKE_CURRENT_SOURCE_DIR}/../../wasm-micro-runtime/build-scripts/runtime_lib.cmake")
+            set(WAMR_ROOT_DIR "${CMAKE_CURRENT_SOURCE_DIR}/../../wasm-micro-runtime")
+        else()
+            message(FATAL_ERROR "WAMR backend requires specifying Halide_WAMR_ROOT_DIR or cloning wasm-micro-runtime adjacent to the Halide repository.")
+        endif()
+    else()
+        set(WAMR_ROOT_DIR "${Halide_WAMR_ROOT_DIR}")
+    endif()
+
+    set(WAMR_BUILD_PLATFORM "linux")
+    set(WAMR_BUILD_TARGET "X86_64")
+    set(WAMR_BUILD_INTERP 1)
+    set(WAMR_BUILD_FAST_INTERP 1)
+    set(WAMR_BUILD_REF_TYPES 1)
+    set(WAMR_BUILD_SIMD 1)
+    set(WAMR_BUILD_LIB_SIMDE 1)
+    include(${WAMR_ROOT_DIR}/build-scripts/runtime_lib.cmake)
+    add_library(wamr_lib STATIC ${WAMR_RUNTIME_LIB_SOURCE})
+    target_link_libraries(Halide PRIVATE wamr_lib)
+    target_compile_definitions(Halide PRIVATE WITH_WAMR)
+    target_include_directories(Halide PRIVATE "${WAMR_ROOT_DIR}/core/iwasm/include")
 elseif (Halide_WASM_BACKEND)
     message(FATAL_ERROR "Unknown Halide_WASM_BACKEND `${Halide_WASM_BACKEND}`")
 endif ()