diff options
Diffstat (limited to 'src/codegen.cpp')
| -rw-r--r-- | src/codegen.cpp | 32 |
1 files changed, 32 insertions, 0 deletions
diff --git a/src/codegen.cpp b/src/codegen.cpp index 22cb975205..d659e27d86 100644 --- a/src/codegen.cpp +++ b/src/codegen.cpp @@ -974,6 +974,8 @@ static Buf *panic_msg_buf(PanicMsgId msg_id) { return buf_create_from_str("resumed a non-suspended function"); case PanicMsgIdBadSentinel: return buf_create_from_str("sentinel mismatch"); + case PanicMsgIdShxTooBigRhs: + return buf_create_from_str("shift amount is greater than the type size"); } zig_unreachable(); } @@ -2841,6 +2843,26 @@ static LLVMValueRef gen_rem(CodeGen *g, bool want_runtime_safety, bool want_fast } +static void gen_shift_rhs_check(CodeGen *g, ZigType *lhs_type, ZigType *rhs_type, LLVMValueRef value) { + // We only check if the rhs value of the shift expression is greater or + // equal to the number of bits of the lhs if it's not a power of two, + // otherwise the check is useful as the allowed values are limited by the + // operand type itself + if (!is_power_of_2(lhs_type->data.integral.bit_count)) { + LLVMValueRef bit_count_value = LLVMConstInt(get_llvm_type(g, rhs_type), + lhs_type->data.integral.bit_count, false); + LLVMValueRef less_than_bit = LLVMBuildICmp(g->builder, LLVMIntULT, value, bit_count_value, ""); + LLVMBasicBlockRef fail_block = LLVMAppendBasicBlock(g->cur_fn_val, "CheckFail"); + LLVMBasicBlockRef ok_block = LLVMAppendBasicBlock(g->cur_fn_val, "CheckOk"); + LLVMBuildCondBr(g->builder, less_than_bit, ok_block, fail_block); + + LLVMPositionBuilderAtEnd(g->builder, fail_block); + gen_safety_crash(g, PanicMsgIdShxTooBigRhs); + + LLVMPositionBuilderAtEnd(g->builder, ok_block); + } +} + static LLVMValueRef ir_render_bin_op(CodeGen *g, IrExecutableGen *executable, IrInstGenBinOp *bin_op_instruction) { @@ -2949,6 +2971,11 @@ static LLVMValueRef ir_render_bin_op(CodeGen *g, IrExecutableGen *executable, { assert(scalar_type->id == ZigTypeIdInt); LLVMValueRef op2_casted = gen_widen_or_shorten(g, false, op2->value->type, scalar_type, op2_value); + + if (want_runtime_safety) { + gen_shift_rhs_check(g, scalar_type, op2->value->type, op2_value); + } + bool is_sloppy = (op_id == IrBinOpBitShiftLeftLossy); if (is_sloppy) { return LLVMBuildShl(g->builder, op1_value, op2_casted, ""); @@ -2965,6 +2992,11 @@ static LLVMValueRef ir_render_bin_op(CodeGen *g, IrExecutableGen *executable, { assert(scalar_type->id == ZigTypeIdInt); LLVMValueRef op2_casted = gen_widen_or_shorten(g, false, op2->value->type, scalar_type, op2_value); + + if (want_runtime_safety) { + gen_shift_rhs_check(g, scalar_type, op2->value->type, op2_value); + } + bool is_sloppy = (op_id == IrBinOpBitShiftRightLossy); if (is_sloppy) { if (scalar_type->data.integral.is_signed) { |