Fix subsetted build issues with arm32/64, hexagon. Fixes #5744. Fixes #5628 (#5745) (#5753)

(cherry picked from commit d053463)

Author: alexreinking

src/CodeGen_Hexagon.cpp

@@ -2313,6 +2313,7 @@ std::unique_ptr<CodeGen_Posix> new_CodeGen_Hexagon(const Target &target, llvm::L
 
 std::unique_ptr<CodeGen_Posix> new_CodeGen_Hexagon(const Target &target, llvm::LLVMContext &context) {
     user_error << "hexagon not enabled for this build of Halide.\n";
+    return nullptr;
 }
 
 #endif  // WITH_HEXAGON

src/LLVM_Runtime_Linker.cpp

@@ -34,21 +34,17 @@ std::unique_ptr<llvm::Module> parse_bitcode_file(llvm::StringRef buf, llvm::LLVM
         return parse_bitcode_file(sb, context, #mod);                                     \
     }
 
-#define DECLARE_NO_INITMOD(mod)                                                        \
-    std::unique_ptr<llvm::Module> get_initmod_##mod(llvm::LLVMContext *, bool, bool) { \
-        user_error << "Halide was compiled without support for this target\n";         \
-        return std::unique_ptr<llvm::Module>();                                        \
-    }                                                                                  \
-    std::unique_ptr<llvm::Module> get_initmod_##mod##_ll(llvm::LLVMContext *) {        \
-        user_error << "Halide was compiled without support for this target\n";         \
-        return std::unique_ptr<llvm::Module>();                                        \
+#define DECLARE_NO_INITMOD(mod)                                                                        \
+    std::unique_ptr<llvm::Module> get_initmod_##mod(llvm::LLVMContext *, bool = false, bool = false) { \
+        user_error << "Halide was compiled without support for this target\n";                         \
+        return std::unique_ptr<llvm::Module>();                                                        \
+    }                                                                                                  \
+    std::unique_ptr<llvm::Module> get_initmod_##mod##_ll(llvm::LLVMContext *) {                        \
+        user_error << "Halide was compiled without support for this target\n";                         \
+        return std::unique_ptr<llvm::Module>();                                                        \
     }
 
-#define DECLARE_CPP_INITMOD(mod)                                                                            \
-    DECLARE_INITMOD(mod##_32_debug)                                                                         \
-    DECLARE_INITMOD(mod##_64_debug)                                                                         \
-    DECLARE_INITMOD(mod##_32)                                                                               \
-    DECLARE_INITMOD(mod##_64)                                                                               \
+#define DECLARE_CPP_INITMOD_LOOKUP(mod)                                                                     \
     std::unique_ptr<llvm::Module> get_initmod_##mod(llvm::LLVMContext *context, bool bits_64, bool debug) { \
         if (bits_64) {                                                                                      \
             if (debug) {                                                                                    \
@@ -65,6 +61,13 @@ std::unique_ptr<llvm::Module> parse_bitcode_file(llvm::StringRef buf, llvm::LLVM
         }                                                                                                   \
     }
 
+#define DECLARE_CPP_INITMOD(mod)    \
+    DECLARE_INITMOD(mod##_32_debug) \
+    DECLARE_INITMOD(mod##_64_debug) \
+    DECLARE_INITMOD(mod##_32)       \
+    DECLARE_INITMOD(mod##_64)       \
+    DECLARE_CPP_INITMOD_LOOKUP(mod)
+
 #define DECLARE_LL_INITMOD(mod) \
     DECLARE_INITMOD(mod##_ll)
 
@@ -197,14 +200,34 @@ DECLARE_LL_INITMOD(ptx_compute_30)
 DECLARE_LL_INITMOD(ptx_compute_35)
 #endif  // WITH_NVPTX
 
-#ifdef WITH_D3D12
+#if defined(WITH_D3D12) && defined(WITH_X86)
 DECLARE_CPP_INITMOD(windows_d3d12compute_x86)
-DECLARE_CPP_INITMOD(windows_d3d12compute_arm)
 #else
 DECLARE_NO_INITMOD(windows_d3d12compute_x86)
-DECLARE_NO_INITMOD(windows_d3d12compute_arm)
 #endif
 
+#ifdef WITH_D3D12
+#ifdef WITH_ARM
+DECLARE_INITMOD(windows_d3d12compute_arm_32)
+DECLARE_INITMOD(windows_d3d12compute_arm_32_debug)
+#else
+DECLARE_NO_INITMOD(windows_d3d12compute_arm_32)
+DECLARE_NO_INITMOD(windows_d3d12compute_arm_32_debug)
+#endif
+
+#ifdef WITH_AARCH64
+DECLARE_INITMOD(windows_d3d12compute_arm_64)
+DECLARE_INITMOD(windows_d3d12compute_arm_64_debug)
+#else
+DECLARE_NO_INITMOD(windows_d3d12compute_arm_64)
+DECLARE_NO_INITMOD(windows_d3d12compute_arm_64_debug)
+#endif
+
+DECLARE_CPP_INITMOD_LOOKUP(windows_d3d12compute_arm)
+#else
+DECLARE_NO_INITMOD(windows_d3d12compute_arm)
+#endif  // WITH_D3D12
+
 #ifdef WITH_X86
 DECLARE_LL_INITMOD(x86_avx2)
 DECLARE_LL_INITMOD(x86_avx)

src/runtime/CMakeLists.txt

@@ -186,10 +186,12 @@ foreach (i IN LISTS RUNTIME_CPP)
                 endif ()
             # Windows on ARM
             elseif (i MATCHES "windows_.*_arm$")
-                if (j EQUAL 32)
+                if (j EQUAL 32 AND TARGET_ARM)
                     set(TARGET "arm-unknown-windows-unknown")
-                else ()
+                elseif (j EQUAL 64 AND TARGET_AARCH64)
                     set(TARGET "aarch64-unknown-windows-unknown")
+                else ()
+                    continue()
                 endif ()
             # Windows Generic
             else()