[llvm] 4c44dcf - Support soft failure on DWP section overflow, producing a truncated but valid DWP(#71902)
via llvm-commits
llvm-commits at lists.llvm.org
Fri Dec 1 12:01:32 PST 2023
Author: Jinjie Huang
Date: 2023-12-01T12:01:22-08:00
New Revision: 4c44dcffd5f1557bde2c21773221081437308895
URL: https://github.com/llvm/llvm-project/commit/4c44dcffd5f1557bde2c21773221081437308895
DIFF: https://github.com/llvm/llvm-project/commit/4c44dcffd5f1557bde2c21773221081437308895.diff
LOG: Support soft failure on DWP section overflow, producing a truncated but valid DWP(#71902)
When 'ContinueOnCuIndexOverflow' enables without this modification, the
forcibly generated '.dwp' won't be recognized by Debugger(gdb 10.1)
correctly.
<img width="657" alt="image"
src="https://github.com/llvm/llvm-project/assets/150100070/31732775-2548-453a-a47a-fa04c6d05fe9">
it looks like there's a problem with processing the dwarf header, which
makes debugging completely impossible. (unless the consumer walks the debug_info section to rebuild that column (if that's the only section that overflowed - if it's another section, there's no recovery))
**About patch:**
When llvm-dwp enables option '--continue-on-cu-index-overflow=soft-stop'
and recognizes the overflow problem , it will stop packing and generate
the '.dwp' file at once, discarding any DWO files that would not fit
within the 32 bit/4GB limits of the format.
<img width="625" alt="image"
src="https://github.com/llvm/llvm-project/assets/150100070/77d6be24-262b-4f4c-afc0-9a6c49e133c7">
Added:
Modified:
llvm/include/llvm/DWP/DWP.h
llvm/lib/DWP/DWP.cpp
llvm/tools/llvm-dwp/Opts.td
llvm/tools/llvm-dwp/llvm-dwp.cpp
Removed:
################################################################################
diff --git a/llvm/include/llvm/DWP/DWP.h b/llvm/include/llvm/DWP/DWP.h
index e33133d38ae008e..9925deaa636b36b 100644
--- a/llvm/include/llvm/DWP/DWP.h
+++ b/llvm/include/llvm/DWP/DWP.h
@@ -15,6 +15,12 @@
#include <vector>
namespace llvm {
+enum OnCuIndexOverflow {
+ HardStop,
+ SoftStop,
+ Continue,
+};
+
struct UnitIndexEntry {
DWARFUnitIndex::Entry::SectionContribution Contributions[8];
std::string Name;
@@ -61,7 +67,7 @@ struct CompileUnitIdentifiers {
};
Error write(MCStreamer &Out, ArrayRef<std::string> Inputs,
- bool ContinueOnCuIndexOverflow);
+ OnCuIndexOverflow OverflowOptValue);
unsigned getContributionIndex(DWARFSectionKind Kind, uint32_t IndexVersion);
diff --git a/llvm/lib/DWP/DWP.cpp b/llvm/lib/DWP/DWP.cpp
index 89101ca7e5736ba..77bd22d1f071c6e 100644
--- a/llvm/lib/DWP/DWP.cpp
+++ b/llvm/lib/DWP/DWP.cpp
@@ -183,14 +183,19 @@ static StringRef getSubsection(StringRef Section,
static Error sectionOverflowErrorOrWarning(uint32_t PrevOffset,
uint32_t OverflowedOffset,
StringRef SectionName,
- bool ContinueOnCuIndexOverflow) {
+ OnCuIndexOverflow OverflowOptValue,
+ bool &AnySectionOverflow) {
std::string Msg =
(SectionName +
Twine(" Section Contribution Offset overflow 4G. Previous Offset ") +
Twine(PrevOffset) + Twine(", After overflow offset ") +
Twine(OverflowedOffset) + Twine("."))
.str();
- if (ContinueOnCuIndexOverflow) {
+ if (OverflowOptValue == OnCuIndexOverflow::Continue) {
+ WithColor::defaultWarningHandler(make_error<DWPError>(Msg));
+ return Error::success();
+ } else if (OverflowOptValue == OnCuIndexOverflow::SoftStop) {
+ AnySectionOverflow = true;
WithColor::defaultWarningHandler(make_error<DWPError>(Msg));
return Error::success();
}
@@ -201,7 +206,8 @@ static Error addAllTypesFromDWP(
MCStreamer &Out, MapVector<uint64_t, UnitIndexEntry> &TypeIndexEntries,
const DWARFUnitIndex &TUIndex, MCSection *OutputTypes, StringRef Types,
const UnitIndexEntry &TUEntry, uint32_t &TypesOffset,
- unsigned TypesContributionIndex, bool ContinueOnCuIndexOverflow) {
+ unsigned TypesContributionIndex, OnCuIndexOverflow OverflowOptValue,
+ bool &AnySectionOverflow) {
Out.switchSection(OutputTypes);
for (const DWARFUnitIndex::Entry &E : TUIndex.getRows()) {
auto *I = E.getContributions();
@@ -232,9 +238,14 @@ static Error addAllTypesFromDWP(
static_assert(sizeof(OldOffset) == sizeof(TypesOffset));
TypesOffset += C.getLength();
if (OldOffset > TypesOffset) {
- if (Error Err = sectionOverflowErrorOrWarning(
- OldOffset, TypesOffset, "Types", ContinueOnCuIndexOverflow))
+ if (Error Err = sectionOverflowErrorOrWarning(OldOffset, TypesOffset,
+ "Types", OverflowOptValue,
+ AnySectionOverflow))
return Err;
+ if (AnySectionOverflow) {
+ TypesOffset = OldOffset;
+ return Error::success();
+ }
}
}
return Error::success();
@@ -244,7 +255,7 @@ static Error addAllTypesFromTypesSection(
MCStreamer &Out, MapVector<uint64_t, UnitIndexEntry> &TypeIndexEntries,
MCSection *OutputTypes, const std::vector<StringRef> &TypesSections,
const UnitIndexEntry &CUEntry, uint32_t &TypesOffset,
- bool ContinueOnCuIndexOverflow) {
+ OnCuIndexOverflow OverflowOptValue, bool &AnySectionOverflow) {
for (StringRef Types : TypesSections) {
Out.switchSection(OutputTypes);
uint64_t Offset = 0;
@@ -273,9 +284,14 @@ static Error addAllTypesFromTypesSection(
uint32_t OldOffset = TypesOffset;
TypesOffset += C.getLength32();
if (OldOffset > TypesOffset) {
- if (Error Err = sectionOverflowErrorOrWarning(
- OldOffset, TypesOffset, "types", ContinueOnCuIndexOverflow))
+ if (Error Err = sectionOverflowErrorOrWarning(OldOffset, TypesOffset,
+ "Types", OverflowOptValue,
+ AnySectionOverflow))
return Err;
+ if (AnySectionOverflow) {
+ TypesOffset = OldOffset;
+ return Error::success();
+ }
}
}
}
@@ -583,7 +599,7 @@ Error handleSection(
}
Error write(MCStreamer &Out, ArrayRef<std::string> Inputs,
- bool ContinueOnCuIndexOverflow) {
+ OnCuIndexOverflow OverflowOptValue) {
const auto &MCOFI = *Out.getContext().getObjectFileInfo();
MCSection *const StrSection = MCOFI.getDwarfStrDWOSection();
MCSection *const StrOffsetSection = MCOFI.getDwarfStrOffDWOSection();
@@ -613,6 +629,7 @@ Error write(MCStreamer &Out, ArrayRef<std::string> Inputs,
uint32_t ContributionOffsets[8] = {};
uint16_t Version = 0;
uint32_t IndexVersion = 0;
+ bool AnySectionOverflow = false;
DWPStringPool Strings(Out, StrSection);
@@ -687,12 +704,15 @@ Error write(MCStreamer &Out, ArrayRef<std::string> Inputs,
uint32_t SectionIndex = 0;
for (auto &Section : Obj.sections()) {
if (SectionIndex == Index) {
- return sectionOverflowErrorOrWarning(
- OldOffset, ContributionOffsets[Index], *Section.getName(),
- ContinueOnCuIndexOverflow);
+ if (Error Err = sectionOverflowErrorOrWarning(
+ OldOffset, ContributionOffsets[Index], *Section.getName(),
+ OverflowOptValue, AnySectionOverflow))
+ return Err;
}
++SectionIndex;
}
+ if (AnySectionOverflow)
+ break;
}
}
@@ -720,8 +740,14 @@ Error write(MCStreamer &Out, ArrayRef<std::string> Inputs,
C.getLength32()) {
if (Error Err = sectionOverflowErrorOrWarning(
InfoSectionOffset, InfoSectionOffset + C.getLength32(),
- "debug_info", ContinueOnCuIndexOverflow))
+ "debug_info", OverflowOptValue, AnySectionOverflow))
return Err;
+ if (AnySectionOverflow) {
+ if (Header.Version < 5 ||
+ Header.UnitType == dwarf::DW_UT_split_compile)
+ FoundCUUnit = true;
+ break;
+ }
}
UnitOffset += C.getLength32();
@@ -752,6 +778,8 @@ Error write(MCStreamer &Out, ArrayRef<std::string> Inputs,
Info.substr(UnitOffset - C.getLength32(), C.getLength32()));
InfoSectionOffset += C.getLength32();
}
+ if (AnySectionOverflow)
+ break;
}
if (!FoundCUUnit)
@@ -762,9 +790,11 @@ Error write(MCStreamer &Out, ArrayRef<std::string> Inputs,
if (Error Err = addAllTypesFromTypesSection(
Out, TypeIndexEntries, TypesSection, CurTypesSection, CurEntry,
ContributionOffsets[getContributionIndex(DW_SECT_EXT_TYPES, 2)],
- ContinueOnCuIndexOverflow))
+ OverflowOptValue, AnySectionOverflow))
return Err;
}
+ if (AnySectionOverflow)
+ break;
continue;
}
@@ -860,9 +890,11 @@ Error write(MCStreamer &Out, ArrayRef<std::string> Inputs,
if (Error Err = addAllTypesFromDWP(
Out, TypeIndexEntries, TUIndex, OutSection, TypeInputSection,
CurEntry, ContributionOffsets[TypesContributionIndex],
- TypesContributionIndex, ContinueOnCuIndexOverflow))
+ TypesContributionIndex, OverflowOptValue, AnySectionOverflow))
return Err;
}
+ if (AnySectionOverflow)
+ break;
}
if (Version < 5) {
diff --git a/llvm/tools/llvm-dwp/Opts.td b/llvm/tools/llvm-dwp/Opts.td
index c01fa4a12cbafb8..75b56fdb670cf4b 100644
--- a/llvm/tools/llvm-dwp/Opts.td
+++ b/llvm/tools/llvm-dwp/Opts.td
@@ -9,5 +9,7 @@ def version : F<"version", "Display the version of this program">;
def execFileNames : S<"e", "Specify the executable/library files to get the list of *.dwo from.">, MetaVarName<"<filename>">;
def outputFileName : S<"o", "Specify the output file.">, MetaVarName<"<filename>">;
-def continueOnCuIndexOverflow: F<"continue-on-cu-index-overflow", "This turns an error when offset for .debug_*.dwo sections "
- "overfolws into a warning.">, MetaVarName<"<filename>">;
+def continueOnCuIndexOverflow : S<"continue-on-cu-index-overflow", "default = continue, This turns an error when offset "
+ "for .debug_*.dwo sections overfolws into a warning. = soft-stop, This produces a "
+ "truncated but valid DWP file, discarding any DWO files that would not fit within "
+ "the 32 bit/4GB limits of the format.">, MetaVarName<"<filename>">;
\ No newline at end of file
diff --git a/llvm/tools/llvm-dwp/llvm-dwp.cpp b/llvm/tools/llvm-dwp/llvm-dwp.cpp
index f976298dcadc2f4..5cd4c0078a45866 100644
--- a/llvm/tools/llvm-dwp/llvm-dwp.cpp
+++ b/llvm/tools/llvm-dwp/llvm-dwp.cpp
@@ -71,7 +71,7 @@ class DwpOptTable : public opt::GenericOptTable {
// Options
static std::vector<std::string> ExecFilenames;
static std::string OutputFilename;
-static bool ContinueOnCuIndexOverflow;
+static std::string ContinueOption;
static Expected<SmallVector<std::string, 16>>
getDWOFilenames(StringRef ExecFilename) {
@@ -125,6 +125,7 @@ int llvm_dwp_main(int argc, char **argv, const llvm::ToolContext &) {
DwpOptTable Tbl;
llvm::BumpPtrAllocator A;
llvm::StringSaver Saver{A};
+ OnCuIndexOverflow OverflowOptValue = OnCuIndexOverflow::HardStop;
opt::InputArgList Args =
Tbl.parseArgs(argc, argv, OPT_UNKNOWN, Saver, [&](StringRef Msg) {
llvm::errs() << Msg << '\n';
@@ -143,7 +144,15 @@ int llvm_dwp_main(int argc, char **argv, const llvm::ToolContext &) {
}
OutputFilename = Args.getLastArgValue(OPT_outputFileName, "");
- ContinueOnCuIndexOverflow = Args.hasArg(OPT_continueOnCuIndexOverflow);
+ if (Args.hasArg(OPT_continueOnCuIndexOverflow)) {
+ ContinueOption =
+ Args.getLastArgValue(OPT_continueOnCuIndexOverflow, "continue");
+ if (ContinueOption == "soft-stop") {
+ OverflowOptValue = OnCuIndexOverflow::SoftStop;
+ } else {
+ OverflowOptValue = OnCuIndexOverflow::Continue;
+ }
+ }
for (const llvm::opt::Arg *A : Args.filtered(OPT_execFileNames))
ExecFilenames.emplace_back(A->getValue());
@@ -255,7 +264,7 @@ int llvm_dwp_main(int argc, char **argv, const llvm::ToolContext &) {
if (!MS)
return error("no object streamer for target " + TripleName, Context);
- if (auto Err = write(*MS, DWOFilenames, ContinueOnCuIndexOverflow)) {
+ if (auto Err = write(*MS, DWOFilenames, OverflowOptValue)) {
logAllUnhandledErrors(std::move(Err), WithColor::error());
return 1;
}
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