[wasm] Switch to the LLVM wasm backend. (mono/mono#14734)

* [wasm] Switch to the llvm wasm backend.

* [wasm] Packager changes for the wasm backend.

* -s EMULATED_FUNCTION_POINTERS=1 no longer needed.
* Run wasm-strip on the final binary.
* Run opt during AOT.
* Disable the dynamic build for now, it doesn't seem to work with the wasm backend.

* [wasm] Use STACK_MAX instead of STACK_BASE for the bottom limit of the stack.

* [aot] Handle llvmopts= in llvmonly mode as well.

* [wasm] Disable an assertion which is no longer true with the wasm backend.

* [wasm] Disable computed gotos in the interpreter, the wasm backend doesn't support it.

Fix llvm target layout so its compatible with clang compiled code.

* [wasm] Pass llvm-path to the cross compiler.

* [wasm] Fix some problems with the dynamic build, still doesn't work. Fix packaging.

* [wasm] Pass -s DISABLE_EXCEPTION_CATCHING=0 to the runtime build, otherwise catch clauses are not generated in llvm-runtime.cpp.

* [aot] Allow llvmopts= argument multiple times.

* Bump emscripten version to 1.38.34.

* [wasm] Add emscripten-core/emscripten#8457 as a patch.

* [wasm] Compile the aot .bc files to .o in a separate step using emcc, this will help with incremental compilation later.

* [wasm] Source emsdk_set_env.sh instead of emsdk_env.sh the latter calls emsdk construct_env to construct emsdk_set_env.sh which is racy.


Commit migrated from mono/mono@1653239

src/mono/mono/mini/aot-compiler.c

@@ -8071,7 +8071,13 @@ mono_aot_parse_options (const char *aot_options, MonoAotOptions *opts)
 		} else if (!strcmp (arg, "verbose")) {
 			opts->verbose = TRUE;
 		} else if (str_begins_with (arg, "llvmopts=")){
-			opts->llvm_opts = g_strdup (arg + strlen ("llvmopts="));
+			if (opts->llvm_opts) {
+				char *s = g_strdup_printf ("%s %s", opts->llvm_opts, arg + strlen ("llvmopts="));
+				g_free (opts->llvm_opts);
+				opts->llvm_opts = s;
+			} else {
+				opts->llvm_opts = g_strdup (arg + strlen ("llvmopts="));
+			}
 		} else if (str_begins_with (arg, "llvmllc=")){
 			opts->llvm_llc = g_strdup (arg + strlen ("llvmllc="));
 		} else if (!strcmp (arg, "deterministic")) {
@@ -9666,9 +9672,10 @@ emit_llvm_file (MonoAotCompile *acfg)
 #else
 		opts = g_strdup ("-targetlibinfo -no-aa -basicaa -notti -instcombine -simplifycfg -inline-cost -inline -sroa -domtree -early-cse -lazy-value-info -correlated-propagation -simplifycfg -instcombine -simplifycfg -reassociate -domtree -loops -loop-simplify -lcssa -loop-rotate -licm -lcssa -loop-unswitch -instcombine -scalar-evolution -loop-simplify -lcssa -indvars -loop-idiom -loop-deletion -loop-unroll -memdep -gvn -memdep -memcpyopt -sccp -instcombine -lazy-value-info -correlated-propagation -domtree -memdep -adce -simplifycfg -instcombine -strip-dead-prototypes -domtree -verify -place-safepoints -spp-all-backedges");
 #endif
-		if (acfg->aot_opts.llvm_opts) {
-			opts = g_strdup_printf ("%s %s", opts, acfg->aot_opts.llvm_opts);
-		}
+	}
+
+	if (acfg->aot_opts.llvm_opts) {
+		opts = g_strdup_printf ("%s %s", opts, acfg->aot_opts.llvm_opts);
 	}
 
 	command = g_strdup_printf ("\"%sopt\" -f %s -o \"%s\" \"%s\"", acfg->aot_opts.llvm_path, opts, optbc, tempbc);

src/mono/mono/mini/aot-runtime.c

@@ -2797,7 +2797,7 @@ compute_llvm_code_range (MonoAotModule *amodule, guint8 **code_start, guint8 **c
 			addr = get_method (i);
 			gsize val = (gsize)addr;
 			if (val) {
-				g_assert (val > prev);
+				//g_assert (val > prev);
 				if (val < min)
 					min = val;
 				else if (val > max)

src/mono/mono/mini/interp/interp.c

@@ -2802,7 +2802,7 @@ static int opcode_counts[512];
 #define DUMP_INSTR()
 #endif
 
-#ifdef __GNUC__
+#if defined(__GNUC__) && !defined(TARGET_WASM)
 #define USE_COMPUTED_GOTO 1
 #endif
 #if USE_COMPUTED_GOTO

src/mono/mono/mini/mini-wasm.h

@@ -104,8 +104,8 @@ typedef struct {
 #define MONO_ARCH_HAS_REGISTER_ICALL 1
 #define MONO_ARCH_HAVE_PATCH_CODE_NEW 1
 #define MONO_ARCH_HAVE_SDB_TRAMPOLINES 1
-#define MONO_ARCH_LLVM_TARGET_LAYOUT "e-p:32:32-i64:64-v128:32:128-n32-S128"
-#define MONO_ARCH_LLVM_TARGET_TRIPLE "wasm32-unknown-unknown-wasm"
+#define MONO_ARCH_LLVM_TARGET_LAYOUT "e-m:e-p:32:32-i64:64-n32:64-S128"
+#define MONO_ARCH_LLVM_TARGET_TRIPLE "wasm32-unknown-emscripten"
 
 void mono_wasm_debugger_init (void);
 

src/mono/mono/utils/mono-threads-wasm.c

@@ -18,8 +18,9 @@ EMSCRIPTEN_KEEPALIVE
 static int
 wasm_get_stack_base (void)
 {
+	// Return the bottom limit of the stack
 	return EM_ASM_INT ({
-		return STACK_BASE;
+		return STACK_MAX;
 	});
 }
 
@@ -32,7 +33,6 @@ wasm_get_stack_size (void)
 	});
 }
 
-
 int
 mono_thread_info_get_system_max_stack_size (void)
 {