[DebugInfo] Add check for .debug_line minimum_instruction_length of 0

[jhenderson]

Summary

If the minimum_instruction_length of a debug line program is 0, no address advancing via special opcodes, DW_LNS_const_add_pc, and DW_LNS_advance_pc can occur, since the minimum_instruction_length is used in a multiplication. This patch adds a warning reporting when this issue occurs.

Depends on D74819.

[jhenderson]

Rebase and fix a warning.

[probinson]

LGTM

[jhenderson]

Rebase on latest changes.

[jhenderson]

Rebase.

[jhenderson]

Remove unnecessary public.

llvm/lib/DebugInfo/DWARF/DWARFDebugLine.cpp

if (ReportAdvanceAddrProblem && LineTable->Prologue.getVersion() >= 4 &&
     ErrorHandler(createStringError(
         errc::not_supported,
         "line table program at offset 0x%8.8" PRIx64
         " contains a %s opcode at offset 0x%8.8" PRIx64
         ", but the prologue maximum_operations_per_instruction value is %" PRId8
         ", which is unsupported. Assuming a value of 1 instead",
         LineTableOffset, OpcodeName.data(), OpcodeOffset,
         LineTable->Prologue.MaxOpsPerInst));
+  if (ReportAdvanceAddrProblem && LineTable->Prologue.MinInstLength == 0)
+    ErrorHandler(
+        createStringError(errc::invalid_argument,
+                          "line table program at offset 0x%8.8" PRIx64
+                          " contains a %s opcode at offset 0x%8.8" PRIx64
+                          ", but the prologue minimum_instruction_length value "
+                          "is 0, which prevents any address advancing",
+                          LineTableOffset, OpcodeName.data(), OpcodeOffset));
   ReportAdvanceAddrProblem = false;
   uint64_t AddrOffset = OperationAdvance * LineTable->Prologue.MinInstLength;
   Row.Address.Address += AddrOffset;
   return AddrOffset;
 }
 
 DWARFDebugLine::ParsingState::AddrAndAdjustedOpcode
 DWARFDebugLine::ParsingState::advanceAddrForOpcode(uint8_t Opcode,

llvm/unittests/DebugInfo/DWARF/DWARFDebugLineTest.cpp

runTest(/*CheckAdvancePC=*/false,
           "not be adjusted");
 }
 
 INSTANTIATE_TEST_CASE_P(
     LineRangeParams, LineRangeFixture,
     Values(std::make_tuple(0, true),       // Test zero value (error).
            std::make_tuple(14, false)), ); // Test non-zero value (no error).
 
+struct BadMinInstLenFixture : TestWithParam<std::tuple<uint8_t, bool>>,
+                              AdjustAddressFixtureBase {
+  void SetUp() override {
+    std::tie(MinInstLength, IsErrorExpected) = GetParam();
+  }
+
+  uint64_t editPrologue(LineTable &LT) override {
+    DWARFDebugLine::Prologue Prologue = LT.createBasicPrologue();
+    Prologue.MinInstLength = MinInstLength;
+    LT.setPrologue(Prologue);
+    return Prologue.TotalLength + Prologue.sizeofTotalLength();
+  }
+
+  uint64_t getAdjustedAddr(uint64_t Base, uint64_t ConstIncr,
+                           uint64_t SpecialIncr,
+                           uint64_t AdvanceIncr) override {
+    return MinInstLength != 0 ? AdjustAddressFixtureBase::getAdjustedAddr(
+                                    Base, ConstIncr, SpecialIncr, AdvanceIncr)
+                              : Base;
+  }
+
+  uint8_t MinInstLength;
+};
+
+TEST_P(BadMinInstLenFixture, MinInstLengthProblemsReportedCorrectly) {
+  runTest(/*CheckAdvancePC=*/true,
+          "but the prologue minimum_instruction_length value is 0, which "
+          "prevents any address advancing");
+}
+
+INSTANTIATE_TEST_CASE_P(
+    BadMinInstLenParams, BadMinInstLenFixture,
+    Values(std::make_tuple(0, true),      // Test zero value (error).
+           std::make_tuple(1, false)), ); // Test non-zero value (no error).
+
 TEST_F(DebugLineBasicFixture, ParserParsesCorrectly) {
   if (!setupGenerator())
     return;
 
   DWARFDebugLine::SectionParser Parser = setupParser();
 
   EXPECT_EQ(Parser.getOffset(), 0u);
   ASSERT_FALSE(Parser.done());