[DebugInfo] Make most debug line prologue errors non-fatal to parsing

Many of the debug line prologue errors are not inherently fatal. In most
cases, we can make reasonable assumptions and carry on. This patch does
exactly that. In the case of length problems, the approach of "assume
stated length is correct" is taken which means the offset might need
adjusting.

This is a relanding of b94191fe, fixing an LLD test and the LLDB build.

Reviewed by: dblaikie, labath

Differential Revision: https://reviews.llvm.org/D72158

1 files changed, 44 insertions, 12 deletions

diff --git a/llvm/unittests/DebugInfo/DWARF/DWARFDebugLineTest.cpp b/llvm/unittests/DebugInfo/DWARF/DWARFDebugLineTest.cpp
index 731afaf..89c28bc 100644
--- a/llvm/unittests/DebugInfo/DWARF/DWARFDebugLineTest.cpp
+++ b/llvm/unittests/DebugInfo/DWARF/DWARFDebugLineTest.cpp
@@ -359,10 +359,15 @@ TEST_F(DebugLineBasicFixture, ErrorForInvalidV5IncludeDirTable) {
 

   generate();

 

-  checkGetOrParseLineTableEmitsFatalError(

+  auto ExpectedLineTable = Line.getOrParseLineTable(LineData, 0, *Context,

+                                                    nullptr, RecordRecoverable);

+  EXPECT_THAT_EXPECTED(ExpectedLineTable, Succeeded());

+

+  checkError(

       {"parsing line table prologue at 0x00000000 found an invalid directory "

        "or file table description at 0x00000014",

-       "failed to parse entry content descriptions because no path was found"});

+       "failed to parse entry content descriptions because no path was found"},

+      std::move(Recoverable));

 }

 

 TEST_P(DebugLineParameterisedFixture, ErrorForTooLargePrologueLength) {

@@ -379,14 +384,24 @@ TEST_P(DebugLineParameterisedFixture, ErrorForTooLargePrologueLength) {
 

   generate();

 

+  auto ExpectedLineTable = Line.getOrParseLineTable(LineData, 0, *Context,

+                                                    nullptr, RecordRecoverable);

+  ASSERT_THAT_EXPECTED(ExpectedLineTable, Succeeded());

+  DWARFDebugLine::LineTable Result(**ExpectedLineTable);

+  // Undo the earlier modification so that it can be compared against a

+  // "default" prologue.

+  --Result.Prologue.PrologueLength;

+  checkDefaultPrologue(Version, Format, Result.Prologue, 0);

+

   uint64_t ExpectedEnd =

       Prologue.TotalLength + 1 + Prologue.sizeofTotalLength();

-  checkGetOrParseLineTableEmitsFatalError(

+  checkError(

       (Twine("parsing line table prologue at 0x00000000 should have ended at "

              "0x000000") +

        Twine::utohexstr(ExpectedEnd) + " but it ended at 0x000000" +

        Twine::utohexstr(ExpectedEnd - 1))

-          .str());

+          .str(),

+      std::move(Recoverable));

 }

 

 TEST_P(DebugLineParameterisedFixture, ErrorForTooShortPrologueLength) {

@@ -408,16 +423,29 @@ TEST_P(DebugLineParameterisedFixture, ErrorForTooShortPrologueLength) {
 

   generate();

 

+  auto ExpectedLineTable = Line.getOrParseLineTable(LineData, 0, *Context,

+                                                    nullptr, RecordRecoverable);

+  ASSERT_THAT_EXPECTED(ExpectedLineTable, Succeeded());

+  DWARFDebugLine::LineTable Result(**ExpectedLineTable);

+  // Undo the earlier modification so that it can be compared against a

+  // "default" prologue.

+  if (Version < 5)

+    Result.Prologue.PrologueLength += 2;

+  else

+    Result.Prologue.PrologueLength += 1;

+  checkDefaultPrologue(Version, Format, Result.Prologue, 0);

+

   uint64_t ExpectedEnd =

       Prologue.TotalLength - 1 + Prologue.sizeofTotalLength();

   if (Version < 5)

     --ExpectedEnd;

-  checkGetOrParseLineTableEmitsFatalError(

+  checkError(

       (Twine("parsing line table prologue at 0x00000000 should have ended at "

              "0x000000") +

        Twine::utohexstr(ExpectedEnd) + " but it ended at 0x000000" +

        Twine::utohexstr(ExpectedEnd + 1))

-          .str());

+          .str(),

+      std::move(Recoverable));

 }

 

 INSTANTIATE_TEST_CASE_P(

@@ -636,14 +664,15 @@ TEST_F(DebugLineBasicFixture, ParserSkipsCorrectly) {
   EXPECT_EQ(Parser.getOffset(), 0u);

   ASSERT_FALSE(Parser.done());

 

-  Parser.skip(RecordUnrecoverable);

+  Parser.skip(RecordRecoverable, RecordUnrecoverable);

   EXPECT_EQ(Parser.getOffset(), 62u);

   ASSERT_FALSE(Parser.done());

 

-  Parser.skip(RecordUnrecoverable);

+  Parser.skip(RecordRecoverable, RecordUnrecoverable);

   EXPECT_EQ(Parser.getOffset(), 136u);

   EXPECT_TRUE(Parser.done());

 

+  EXPECT_FALSE(Recoverable);

   EXPECT_FALSE(Unrecoverable);

 }

 

@@ -688,10 +717,11 @@ TEST_F(DebugLineBasicFixture, ParserMovesToEndForBadLengthWhenSkipping) {
   generate();

 

   DWARFDebugLine::SectionParser Parser(LineData, *Context, CUs, TUs);

-  Parser.skip(RecordUnrecoverable);

+  Parser.skip(RecordRecoverable, RecordUnrecoverable);

 

   EXPECT_EQ(Parser.getOffset(), 4u);

   EXPECT_TRUE(Parser.done());

+  EXPECT_FALSE(Recoverable);

 

   checkError("parsing line table prologue at offset 0x00000000 unsupported "

              "reserved unit length found of value 0xfffffff0",

@@ -767,11 +797,12 @@ TEST_F(DebugLineBasicFixture,
   generate();

 

   DWARFDebugLine::SectionParser Parser(LineData, *Context, CUs, TUs);

-  Parser.skip(RecordUnrecoverable);

+  Parser.skip(RecordRecoverable, RecordUnrecoverable);

   ASSERT_FALSE(Parser.done());

-  Parser.skip(RecordUnrecoverable);

+  Parser.skip(RecordRecoverable, RecordUnrecoverable);

 

   EXPECT_TRUE(Parser.done());

+  EXPECT_FALSE(Recoverable);

 

   checkError({"parsing line table prologue at offset 0x00000000 found "

               "unsupported version 0x00",

@@ -789,9 +820,10 @@ TEST_F(DebugLineBasicFixture, ParserIgnoresNonPrologueErrorsWhenSkipping) {
   generate();

 

   DWARFDebugLine::SectionParser Parser(LineData, *Context, CUs, TUs);

-  Parser.skip(RecordUnrecoverable);

+  Parser.skip(RecordRecoverable, RecordUnrecoverable);

 

   EXPECT_TRUE(Parser.done());

+  EXPECT_FALSE(Recoverable);

   EXPECT_FALSE(Unrecoverable);

 }