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[mono][wasm] Only catch the exception thrown by mono_llvm_cpp_throw_e… #92040

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Merged
merged 1 commit into from
Sep 14, 2023
Merged

[mono][wasm] Only catch the exception thrown by mono_llvm_cpp_throw_e… #92040

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5 changes: 4 additions & 1 deletion src/mono/mono/mini/llvm-intrinsics.h
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Original file line number Diff line number Diff line change
Expand Up @@ -107,7 +107,7 @@ INTRINS_OVR_TAG(SIMD_CEIL, ceil, Generic, Scalar | V64 | V128 | R4 | R8)
INTRINS_OVR_TAG(SIMD_TRUNC, trunc, Generic, Scalar | V64 | V128 | R4 | R8)
INTRINS_OVR_TAG(SIMD_ROUND, round, Generic, Scalar | V64 | V128 | R4 | R8)
INTRINS_OVR_TAG(SIMD_NEAREST, nearbyint, Generic, V64 | V128 | R4 | R8)

INTRINS(EH_TYPEID_FOR, eh_typeid_for, Generic)
#if LLVM_API_VERSION >= 1400
INTRINS_OVR_TAG(ROUNDEVEN, roundeven, Generic, Scalar | V64 | V128 | R4 | R8)
#endif
Expand Down Expand Up @@ -302,6 +302,9 @@ INTRINS_OVR(WASM_SUB_SAT_SIGNED_V8, wasm_sub_sat_signed, Wasm, sse_i2_t)
INTRINS_OVR(WASM_SUB_SAT_UNSIGNED_V16, wasm_sub_sat_unsigned, Wasm, sse_i1_t)
INTRINS_OVR(WASM_SUB_SAT_UNSIGNED_V8, wasm_sub_sat_unsigned, Wasm, sse_i2_t)
INTRINS(WASM_SWIZZLE, wasm_swizzle, Wasm)
INTRINS(WASM_GET_EXCEPTION, wasm_get_exception, Wasm)
INTRINS(WASM_GET_EHSELECTOR, wasm_get_ehselector, Wasm)
INTRINS(WASM_RETHROW, wasm_rethrow, Wasm)
#endif
#if defined(TARGET_ARM64)
INTRINS_OVR(BITREVERSE_I32, bitreverse, Generic, LLVMInt32Type ())
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41 changes: 40 additions & 1 deletion src/mono/mono/mini/mini-llvm.c
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Expand Up @@ -5001,8 +5001,47 @@ emit_llvmonly_landing_pad (EmitContext *ctx, int group_index, int group_size)
LLVMPositionBuilderAtEnd (builder, catch_bb);

LLVMValueRef catchpad_args [1];
catchpad_args [0] = LLVMConstNull (pointer_type (LLVMInt8Type ()));
catchpad_args [0] = ctx->module->sentinel_exception;
catchpad = LLVMBuildCatchPad (builder, lpad, catchpad_args, 1, "");

// The ifdef is needed because of INTRINS_WASM
#ifdef TARGET_WASM
// LLVM seems to require at least the following code sequence
// %7 = catchpad within %5 [ptr @typeinfo for int*]
// %8 = tail call ptr @llvm.wasm.get.exception(token %7)
// %9 = tail call i32 @llvm.wasm.get.ehselector(token %7)

LLVMValueRef args [] = { catchpad };
LLVMValueRef call = call_intrins (ctx, INTRINS_WASM_GET_EXCEPTION, args, "");
LLVMSetTailCall (call, TRUE);
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@SingleAccretion SingleAccretion Sep 14, 2023

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I am pretty sure there is no need for the tail annotation and Clang just adds it because that's what it does for most calls.

LLVMValueRef sel_call = call_intrins (ctx, INTRINS_WASM_GET_EHSELECTOR, args, "");
LLVMSetTailCall (sel_call, TRUE);

//%10 = tail call i32 @llvm.eh.typeid.for(ptr nonnull @typeinfo for int*) #5, !dbg !31
//%11 = icmp eq i32 %9, %10, !dbg !31
//br i1 %11, label %12, label %14, !dbg !31

LLVMValueRef typeid_args [] = { ctx->module->sentinel_exception };
LLVMValueRef typeid = call_intrins (ctx, INTRINS_EH_TYPEID_FOR, typeid_args, "");
LLVMSetTailCall (typeid, TRUE);

LLVMValueRef cmp = LLVMBuildICmp (builder, LLVMIntEQ, sel_call, typeid, "");

LLVMBasicBlockRef ex_bb = gen_bb (ctx, "CATCH_BB");
LLVMBasicBlockRef noex_bb = gen_bb (ctx, "NOCATCH_BB");

LLVMBuildCondBr (ctx->builder, cmp, ex_bb, noex_bb);

/* No catch case */
//call void @llvm.wasm.rethrow() #3 [ "funclet"(token %7) ], !dbg !34
//unreachable, !dbg !34
LLVMPositionBuilderAtEnd (builder, noex_bb);
call_intrins (ctx, INTRINS_WASM_RETHROW, args, "");
LLVMBuildUnreachable (builder);

/* Catch case */
LLVMPositionBuilderAtEnd (builder, ex_bb);
#endif
} else {
MonoBasicBlock *handler_bb = cfg->cil_offset_to_bb [CLAUSE_START (group_start)];
g_assert (handler_bb);
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