1 //:: Check that the different operands of an instruction aren't too large for their bitfields.
  2 
  3 void test_check_bitfield_sizes() {
  4   Hide_errors = true;
  5   run(
  6       "== code 0x1\n"
  7       "01/add 4/mod 3/rm32 1/r32\n"  // add ECX to EBX
  8   );
  9   CHECK_TRACE_CONTENTS(
 10       "error: '4/mod' too large to fit in bitfield mod\n"
 11   );
 12 }
 13 
 14 :(before "End Globals")
 15 map<string, uint32_t> Operand_bound;
 16 :(before "End One-time Setup")
 17 put_new(Operand_bound, "subop", 1<<3);
 18 put_new(Operand_bound, "mod", 1<<2);
 19 put_new(Operand_bound, "rm32", 1<<3);
 20 put_new(Operand_bound, "base", 1<<3);
 21 put_new(Operand_bound, "index", 1<<3);
 22 put_new(Operand_bound, "scale", 1<<2);
 23 put_new(Operand_bound, "r32", 1<<3);
 24 put_new(Operand_bound, "disp8", 1<<8);
 25 put_new(Operand_bound, "disp16", 1<<16);
 26 // no bound needed for disp32
 27 put_new(Operand_bound, "imm8", 1<<8);
 28 // no bound needed for imm32
 29 
 30 :(before "Pack Operands(segment code)")
 31 check_operand_bounds(code);
 32 if (trace_contains_errors()) return;
 33 :(code)
 34 void check_operand_bounds(const segment& code) {
 35   trace(3, "transform") << "-- check operand bounds" << end();
 36   for (int i = 0;  i < SIZE(code.lines);  ++i) {
 37     const line& inst = code.lines.at(i);
 38     for (int j = first_operand(inst);  j < SIZE(inst.words);  ++j)
 39       check_operand_bounds(inst.words.at(j));
 40     if (trace_contains_errors()) return;  // stop at the first mal-formed instruction
 41   }
 42 }
 43 
 44 void check_operand_bounds(const word& w) {
 45   for (map<string, uint32_t>::iterator p = Operand_bound.begin();  p != Operand_bound.end();  ++p) {
 46     if (!has_operand_metadata(w, p->first)) continue;
 47     if (!looks_like_hex_int(w.data)) continue;  // later transforms are on their own to do their own bounds checking
 48     int32_t x = parse_int(w.data);
 49     if (x >= 0) {
 50       if (p->first == "disp8" || p->first == "disp16") {
 51         if (static_cast<uint32_t>(x) >= p->second/2)
 52           raise << "'" << w.original << "' too large to fit in signed bitfield " << p->first << '\n' << end();
 53       }
 54       else {
 55         if (static_cast<uint32_t>(x) >= p->second)
 56           raise << "'" << w.original << "' too large to fit in bitfield " << p->first << '\n' << end();
 57       }
 58     }
 59     else {
 60       // hacky? assuming bound is a power of 2
 61       if (x < -1*static_cast<int32_t>(p->second/2))
 62         raise << "'" << w.original << "' too large to fit in bitfield " << p->first << '\n' << end();
 63     }
 64   }
 65 }
 66 
 67 void test_check_bitfield_sizes_for_imm8() {
 68   run(
 69       "== code 0x1\n"
 70       "c1/shift 4/subop/left 3/mod/direct 1/rm32/ECX 0xff/imm8"  // shift EBX left
 71   );
 72   CHECK(!trace_contains_errors());
 73 }
 74 
 75 void test_check_bitfield_sizes_for_imm8_error() {
 76   Hide_errors = true;
 77   run(
 78       "== code 0x1\n"
 79       "c1/shift 4/subop/left 3/mod/direct 1/rm32/ECX 0x100/imm8"  // shift EBX left
 80   );
 81   CHECK_TRACE_CONTENTS(
 82       "error: '0x100/imm8' too large to fit in bitfield imm8\n"
 83   );
 84 }
 85 
 86 void test_check_bitfield_sizes_for_negative_imm8() {
 87   run(
 88       "== code 0x1\n"
 89       "c1/shift 4/subop/left 3/mod/direct 1/rm32/ECX -0x80/imm8"  // shift EBX left
 90   );
 91   CHECK(!trace_contains_errors());
 92 }
 93 
 94 void test_check_bitfield_sizes_for_negative_imm8_error() {
 95   Hide_errors = true;
 96   run(
 97       "== code 0x1\n"
 98       "c1/shift 4/subop/left 3/mod/direct 1/rm32/ECX -0x81/imm8"  // shift EBX left
 99   );
100   CHECK_TRACE_CONTENTS(
101       "error: '-0x81/imm8' too large to fit in bitfield imm8\n"
102   );
103 }
104 
105 void test_check_bitfield_sizes_for_disp8() {
106   // not bothering to run
107   transform(
108       "== code 0x1\n"
109       "01/add 1/mod/*+disp8 3/rm32 1/r32 0x7f/disp8\n"  // add ECX to *(EBX+0x7f)
110   );
111   CHECK(!trace_contains_errors());
112 }
113 
114 void test_check_bitfield_sizes_for_disp8_error() {
115   Hide_errors = true;
116   run(
117       "== code 0x1\n"
118       "01/add 1/mod/*+disp8 3/rm32 1/r32 0x80/disp8\n"  // add ECX to *(EBX+0x80)
119   );
120   CHECK_TRACE_CONTENTS(
121       "error: '0x80/disp8' too large to fit in signed bitfield disp8\n"
122   );
123 }
124 
125 void test_check_bitfield_sizes_for_negative_disp8() {
126   // not bothering to run
127   transform(
128       "== code 0x1\n"
129       "01/add 1/mod/*+disp8 3/rm32 1/r32 -0x80/disp8\n"  // add ECX to *(EBX-0x80)
130   );
131   CHECK(!trace_contains_errors());
132 }
133 
134 void test_check_bitfield_sizes_for_negative_disp8_error() {
135   Hide_errors = true;
136   run(
137       "== code 0x1\n"
138       "01/add 1/mod/*+disp8 3/rm32 1/r32 -0x81/disp8\n"  // add ECX to *(EBX-0x81)
139   );
140   CHECK_TRACE_CONTENTS(
141       "error: '-0x81/disp8' too large to fit in bitfield disp8\n"
142   );
143 }