[llvm] r370363 - DWARFDebugLoc: Make parsing and error reporting more robust
Pavel Labath via llvm-commits
llvm-commits at lists.llvm.org
Thu Aug 29 07:26:05 PDT 2019
Author: labath
Date: Thu Aug 29 07:26:05 2019
New Revision: 370363
URL: http://llvm.org/viewvc/llvm-project?rev=370363&view=rev
Log:
DWARFDebugLoc: Make parsing and error reporting more robust
Summary:
While examining this class for possible use in lldb, I noticed two
things:
- it spits out parsing errors directly to stderr
- the loclists parser can incorrectly return valid location lists when
parsing malformed (truncated) data
I improve the stderr situation by making the parseOneLocationList
functions return Expected<T>s. The errors are still dumped to stderr by
their callers, so this is only a partial fix, but it is enough for my
use case, as I intend to parse the locations lists one by one.
I fix the behavior in the truncated scenario by using the newly
introduced DataExtractor Cursor API.
I also add tests for handling the error cases, as they currently have no
coverage.
Reviewers: dblaikie, JDevlieghere, probinson
Subscribers: lldb-commits, llvm-commits
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D63591
Added:
llvm/trunk/test/DebugInfo/X86/dwarfdump-debug-loc-error-cases.s
llvm/trunk/test/DebugInfo/X86/dwarfdump-debug-loclists-error-cases.s
Modified:
llvm/trunk/include/llvm/DebugInfo/DWARF/DWARFDebugLoc.h
llvm/trunk/lib/DebugInfo/DWARF/DWARFDebugLoc.cpp
llvm/trunk/lib/DebugInfo/DWARF/DWARFVerifier.cpp
Modified: llvm/trunk/include/llvm/DebugInfo/DWARF/DWARFDebugLoc.h
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/include/llvm/DebugInfo/DWARF/DWARFDebugLoc.h?rev=370363&r1=370362&r2=370363&view=diff
==============================================================================
--- llvm/trunk/include/llvm/DebugInfo/DWARF/DWARFDebugLoc.h (original)
+++ llvm/trunk/include/llvm/DebugInfo/DWARF/DWARFDebugLoc.h Thu Aug 29 07:26:05 2019
@@ -29,7 +29,7 @@ public:
/// The ending address of the instruction range.
uint64_t End;
/// The location of the variable within the specified range.
- SmallString<4> Loc;
+ SmallVector<uint8_t, 4> Loc;
};
/// A list of locations that contain one variable.
@@ -68,8 +68,8 @@ public:
/// Return the location list at the given offset or nullptr.
LocationList const *getLocationListAtOffset(uint64_t Offset) const;
- Optional<LocationList> parseOneLocationList(DWARFDataExtractor Data,
- uint64_t *Offset);
+ static Expected<LocationList>
+ parseOneLocationList(const DWARFDataExtractor &Data, uint64_t *Offset);
};
class DWARFDebugLoclists {
@@ -78,7 +78,7 @@ public:
uint8_t Kind;
uint64_t Value0;
uint64_t Value1;
- SmallVector<char, 4> Loc;
+ SmallVector<uint8_t, 4> Loc;
};
struct LocationList {
@@ -106,8 +106,9 @@ public:
/// Return the location list at the given offset or nullptr.
LocationList const *getLocationListAtOffset(uint64_t Offset) const;
- static Optional<LocationList>
- parseOneLocationList(DataExtractor Data, uint64_t *Offset, unsigned Version);
+ static Expected<LocationList> parseOneLocationList(const DataExtractor &Data,
+ uint64_t *Offset,
+ unsigned Version);
};
} // end namespace llvm
Modified: llvm/trunk/lib/DebugInfo/DWARF/DWARFDebugLoc.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/DebugInfo/DWARF/DWARFDebugLoc.cpp?rev=370363&r1=370362&r2=370363&view=diff
==============================================================================
--- llvm/trunk/lib/DebugInfo/DWARF/DWARFDebugLoc.cpp (original)
+++ llvm/trunk/lib/DebugInfo/DWARF/DWARFDebugLoc.cpp Thu Aug 29 07:26:05 2019
@@ -28,11 +28,10 @@ using namespace llvm;
// expression that LLVM doesn't produce. Guessing the wrong version means we
// won't be able to pretty print expressions in DWARF2 binaries produced by
// non-LLVM tools.
-static void dumpExpression(raw_ostream &OS, ArrayRef<char> Data,
+static void dumpExpression(raw_ostream &OS, ArrayRef<uint8_t> Data,
bool IsLittleEndian, unsigned AddressSize,
const MCRegisterInfo *MRI, DWARFUnit *U) {
- DWARFDataExtractor Extractor(StringRef(Data.data(), Data.size()),
- IsLittleEndian, AddressSize);
+ DWARFDataExtractor Extractor(toStringRef(Data), IsLittleEndian, AddressSize);
DWARFExpression(Extractor, dwarf::DWARF_VERSION, AddressSize).print(OS, MRI, U);
}
@@ -83,47 +82,37 @@ void DWARFDebugLoc::dump(raw_ostream &OS
}
}
-Optional<DWARFDebugLoc::LocationList>
-DWARFDebugLoc::parseOneLocationList(DWARFDataExtractor Data, uint64_t *Offset) {
+Expected<DWARFDebugLoc::LocationList>
+DWARFDebugLoc::parseOneLocationList(const DWARFDataExtractor &Data,
+ uint64_t *Offset) {
LocationList LL;
LL.Offset = *Offset;
+ DataExtractor::Cursor C(*Offset);
// 2.6.2 Location Lists
// A location list entry consists of:
while (true) {
Entry E;
- if (!Data.isValidOffsetForDataOfSize(*Offset, 2 * Data.getAddressSize())) {
- WithColor::error() << "location list overflows the debug_loc section.\n";
- return None;
- }
// 1. A beginning address offset. ...
- E.Begin = Data.getRelocatedAddress(Offset);
+ E.Begin = Data.getRelocatedAddress(C);
// 2. An ending address offset. ...
- E.End = Data.getRelocatedAddress(Offset);
+ E.End = Data.getRelocatedAddress(C);
+ if (Error Err = C.takeError())
+ return std::move(Err);
// The end of any given location list is marked by an end of list entry,
// which consists of a 0 for the beginning address offset and a 0 for the
// ending address offset.
- if (E.Begin == 0 && E.End == 0)
+ if (E.Begin == 0 && E.End == 0) {
+ *Offset = C.tell();
return LL;
-
- if (!Data.isValidOffsetForDataOfSize(*Offset, 2)) {
- WithColor::error() << "location list overflows the debug_loc section.\n";
- return None;
}
- unsigned Bytes = Data.getU16(Offset);
- if (!Data.isValidOffsetForDataOfSize(*Offset, Bytes)) {
- WithColor::error() << "location list overflows the debug_loc section.\n";
- return None;
- }
+ unsigned Bytes = Data.getU16(C);
// A single location description describing the location of the object...
- StringRef str = Data.getData().substr(*Offset, Bytes);
- *Offset += Bytes;
- E.Loc.reserve(str.size());
- llvm::copy(str, std::back_inserter(E.Loc));
+ Data.getU8(C, E.Loc, Bytes);
LL.Entries.push_back(std::move(E));
}
}
@@ -133,67 +122,65 @@ void DWARFDebugLoc::parse(const DWARFDat
AddressSize = data.getAddressSize();
uint64_t Offset = 0;
- while (data.isValidOffset(Offset + data.getAddressSize() - 1)) {
+ while (Offset < data.getData().size()) {
if (auto LL = parseOneLocationList(data, &Offset))
Locations.push_back(std::move(*LL));
- else
+ else {
+ logAllUnhandledErrors(LL.takeError(), WithColor::error());
break;
+ }
}
- if (data.isValidOffset(Offset))
- WithColor::error() << "failed to consume entire .debug_loc section\n";
}
-Optional<DWARFDebugLoclists::LocationList>
-DWARFDebugLoclists::parseOneLocationList(DataExtractor Data, uint64_t *Offset,
- unsigned Version) {
+Expected<DWARFDebugLoclists::LocationList>
+DWARFDebugLoclists::parseOneLocationList(const DataExtractor &Data,
+ uint64_t *Offset, unsigned Version) {
LocationList LL;
LL.Offset = *Offset;
+ DataExtractor::Cursor C(*Offset);
// dwarf::DW_LLE_end_of_list_entry is 0 and indicates the end of the list.
- while (auto Kind =
- static_cast<dwarf::LocationListEntry>(Data.getU8(Offset))) {
-
+ while (auto Kind = static_cast<dwarf::LocationListEntry>(Data.getU8(C))) {
Entry E;
E.Kind = Kind;
switch (Kind) {
case dwarf::DW_LLE_startx_length:
- E.Value0 = Data.getULEB128(Offset);
+ E.Value0 = Data.getULEB128(C);
// Pre-DWARF 5 has different interpretation of the length field. We have
// to support both pre- and standartized styles for the compatibility.
if (Version < 5)
- E.Value1 = Data.getU32(Offset);
+ E.Value1 = Data.getU32(C);
else
- E.Value1 = Data.getULEB128(Offset);
+ E.Value1 = Data.getULEB128(C);
break;
case dwarf::DW_LLE_start_length:
- E.Value0 = Data.getAddress(Offset);
- E.Value1 = Data.getULEB128(Offset);
+ E.Value0 = Data.getAddress(C);
+ E.Value1 = Data.getULEB128(C);
break;
case dwarf::DW_LLE_offset_pair:
- E.Value0 = Data.getULEB128(Offset);
- E.Value1 = Data.getULEB128(Offset);
+ E.Value0 = Data.getULEB128(C);
+ E.Value1 = Data.getULEB128(C);
break;
case dwarf::DW_LLE_base_address:
- E.Value0 = Data.getAddress(Offset);
+ E.Value0 = Data.getAddress(C);
break;
default:
- WithColor::error() << "dumping support for LLE of kind " << (int)Kind
- << " not implemented\n";
- return None;
+ cantFail(C.takeError());
+ return createStringError(errc::illegal_byte_sequence,
+ "LLE of kind %x not supported", (int)Kind);
}
if (Kind != dwarf::DW_LLE_base_address) {
- unsigned Bytes =
- Version >= 5 ? Data.getULEB128(Offset) : Data.getU16(Offset);
+ unsigned Bytes = Version >= 5 ? Data.getULEB128(C) : Data.getU16(C);
// A single location description describing the location of the object...
- StringRef str = Data.getData().substr(*Offset, Bytes);
- *Offset += Bytes;
- E.Loc.resize(str.size());
- llvm::copy(str, E.Loc.begin());
+ Data.getU8(C, E.Loc, Bytes);
}
LL.Entries.push_back(std::move(E));
}
+ if (Error Err = C.takeError())
+ return std::move(Err);
+ *Offset = C.tell();
return LL;
}
@@ -202,11 +189,13 @@ void DWARFDebugLoclists::parse(DataExtra
AddressSize = data.getAddressSize();
uint64_t Offset = 0;
- while (data.isValidOffset(Offset)) {
+ while (Offset < data.getData().size()) {
if (auto LL = parseOneLocationList(data, &Offset, Version))
Locations.push_back(std::move(*LL));
- else
+ else {
+ logAllUnhandledErrors(LL.takeError(), WithColor::error());
return;
+ }
}
}
Modified: llvm/trunk/lib/DebugInfo/DWARF/DWARFVerifier.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/DebugInfo/DWARF/DWARFVerifier.cpp?rev=370363&r1=370362&r2=370363&view=diff
==============================================================================
--- llvm/trunk/lib/DebugInfo/DWARF/DWARFVerifier.cpp (original)
+++ llvm/trunk/lib/DebugInfo/DWARF/DWARFVerifier.cpp Thu Aug 29 07:26:05 2019
@@ -466,9 +466,9 @@ unsigned DWARFVerifier::verifyDebugInfoA
ReportError("DIE has invalid DW_AT_stmt_list encoding:");
break;
case DW_AT_location: {
- auto VerifyLocationExpr = [&](StringRef D) {
+ auto VerifyLocationExpr = [&](ArrayRef<uint8_t> D) {
DWARFUnit *U = Die.getDwarfUnit();
- DataExtractor Data(D, DCtx.isLittleEndian(), 0);
+ DataExtractor Data(toStringRef(D), DCtx.isLittleEndian(), 0);
DWARFExpression Expression(Data, U->getVersion(),
U->getAddressByteSize());
bool Error = llvm::any_of(Expression, [](DWARFExpression::Operation &Op) {
@@ -479,7 +479,7 @@ unsigned DWARFVerifier::verifyDebugInfoA
};
if (Optional<ArrayRef<uint8_t>> Expr = AttrValue.Value.getAsBlock()) {
// Verify inlined location.
- VerifyLocationExpr(llvm::toStringRef(*Expr));
+ VerifyLocationExpr(*Expr);
} else if (auto LocOffset = AttrValue.Value.getAsSectionOffset()) {
// Verify location list.
if (auto DebugLoc = DCtx.getDebugLoc())
@@ -1277,9 +1277,9 @@ static bool isVariableIndexable(const DW
if (!Location)
return false;
- auto ContainsInterestingOperators = [&](StringRef D) {
+ auto ContainsInterestingOperators = [&](ArrayRef<uint8_t> D) {
DWARFUnit *U = Die.getDwarfUnit();
- DataExtractor Data(D, DCtx.isLittleEndian(), U->getAddressByteSize());
+ DataExtractor Data(toStringRef(D), DCtx.isLittleEndian(), U->getAddressByteSize());
DWARFExpression Expression(Data, U->getVersion(), U->getAddressByteSize());
return any_of(Expression, [](DWARFExpression::Operation &Op) {
return !Op.isError() && (Op.getCode() == DW_OP_addr ||
@@ -1290,7 +1290,7 @@ static bool isVariableIndexable(const DW
if (Optional<ArrayRef<uint8_t>> Expr = Location->getAsBlock()) {
// Inlined location.
- if (ContainsInterestingOperators(toStringRef(*Expr)))
+ if (ContainsInterestingOperators(*Expr))
return true;
} else if (Optional<uint64_t> Offset = Location->getAsSectionOffset()) {
// Location list.
Added: llvm/trunk/test/DebugInfo/X86/dwarfdump-debug-loc-error-cases.s
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/DebugInfo/X86/dwarfdump-debug-loc-error-cases.s?rev=370363&view=auto
==============================================================================
--- llvm/trunk/test/DebugInfo/X86/dwarfdump-debug-loc-error-cases.s (added)
+++ llvm/trunk/test/DebugInfo/X86/dwarfdump-debug-loc-error-cases.s Thu Aug 29 07:26:05 2019
@@ -0,0 +1,58 @@
+# RUN: llvm-mc %s -filetype obj -triple x86_64-pc-linux --defsym CASE1=0 -o %t1.o
+# RUN: llvm-dwarfdump -debug-loc %t1.o 2>&1 | FileCheck %s
+
+# RUN: llvm-mc %s -filetype obj -triple x86_64-pc-linux --defsym CASE2=0 -o %t2.o
+# RUN: llvm-dwarfdump -debug-loc %t2.o 2>&1 | FileCheck %s
+
+# RUN: llvm-mc %s -filetype obj -triple x86_64-pc-linux --defsym CASE3=0 -o %t3.o
+# RUN: llvm-dwarfdump -debug-loc %t3.o 2>&1 | FileCheck %s
+
+# RUN: llvm-mc %s -filetype obj -triple x86_64-pc-linux --defsym CASE4=0 -o %t4.o
+# RUN: llvm-dwarfdump -debug-loc %t4.o 2>&1 | FileCheck %s
+
+# RUN: llvm-mc %s -filetype obj -triple x86_64-pc-linux --defsym CASE5=0 -o %t5.o
+# RUN: llvm-dwarfdump -debug-loc %t5.o 2>&1 | FileCheck %s
+
+# RUN: llvm-mc %s -filetype obj -triple x86_64-pc-linux --defsym CASE6=0 -o %t6.o
+# RUN: llvm-dwarfdump -debug-loc %t6.o 2>&1 | FileCheck %s
+
+# CHECK: error: unexpected end of data
+
+.section .debug_loc,"", at progbits
+.ifdef CASE1
+ .byte 1 # bogus
+.endif
+.ifdef CASE2
+ .long 0 # starting offset
+.endif
+.ifdef CASE3
+ .long 0 # starting offset
+ .long 1 # ending offset
+.endif
+.ifdef CASE4
+ .long 0 # starting offset
+ .long 1 # ending offset
+ .word 0 # Loc expr size
+.endif
+.ifdef CASE5
+ .long 0 # starting offset
+ .long 1 # ending offset
+ .word 0 # Loc expr size
+ .long 0 # starting offset
+.endif
+.ifdef CASE6
+ .long 0 # starting offset
+ .long 1 # ending offset
+ .word 0xffff # Loc expr size
+.endif
+
+# A minimal compile unit is needed to deduce the address size of the location
+# lists
+.section .debug_info,"", at progbits
+ .long .Lcu_end0-.Lcu_begin0 # Length of Unit
+.Lcu_begin0:
+ .short 4 # DWARF version number
+ .long 0 # Offset Into Abbrev. Section
+ .byte 8 # Address Size (in bytes)
+ .byte 0 # End Of Children Mark
+.Lcu_end0:
Added: llvm/trunk/test/DebugInfo/X86/dwarfdump-debug-loclists-error-cases.s
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/DebugInfo/X86/dwarfdump-debug-loclists-error-cases.s?rev=370363&view=auto
==============================================================================
--- llvm/trunk/test/DebugInfo/X86/dwarfdump-debug-loclists-error-cases.s (added)
+++ llvm/trunk/test/DebugInfo/X86/dwarfdump-debug-loclists-error-cases.s Thu Aug 29 07:26:05 2019
@@ -0,0 +1,71 @@
+# RUN: llvm-mc %s -filetype obj -triple x86_64-pc-linux --defsym CASE1=0 -o %t1.o
+# RUN: llvm-dwarfdump -debug-loclists %t1.o 2>&1 | FileCheck %s --check-prefix=ULEB
+
+# RUN: llvm-mc %s -filetype obj -triple x86_64-pc-linux --defsym CASE2=0 -o %t2.o
+# RUN: llvm-dwarfdump -debug-loclists %t2.o 2>&1 | FileCheck %s --check-prefix=ULEB
+
+# RUN: llvm-mc %s -filetype obj -triple x86_64-pc-linux --defsym CASE3=0 -o %t3.o
+# RUN: llvm-dwarfdump -debug-loclists %t3.o 2>&1 | FileCheck %s --check-prefix=ULEB
+
+# RUN: llvm-mc %s -filetype obj -triple x86_64-pc-linux --defsym CASE4=0 -o %t4.o
+# RUN: llvm-dwarfdump -debug-loclists %t4.o 2>&1 | FileCheck %s
+
+# RUN: llvm-mc %s -filetype obj -triple x86_64-pc-linux --defsym CASE5=0 -o %t5.o
+# RUN: llvm-dwarfdump -debug-loclists %t5.o 2>&1 | FileCheck %s
+
+# RUN: llvm-mc %s -filetype obj -triple x86_64-pc-linux --defsym CASE6=0 -o %t6.o
+# RUN: llvm-dwarfdump -debug-loclists %t6.o 2>&1 | FileCheck %s
+
+# RUN: llvm-mc %s -filetype obj -triple x86_64-pc-linux --defsym CASE7=0 -o %t7.o
+# RUN: llvm-dwarfdump -debug-loclists %t7.o 2>&1 | FileCheck %s --check-prefix=UNIMPL
+
+# CHECK: error: unexpected end of data
+# ULEB: error: malformed uleb128, extends past end
+# UNIMPL: error: LLE of kind 47 not supported
+
+.section .debug_loclists,"", at progbits
+ .long .Ldebug_loclist_table_end0-.Ldebug_loclist_table_start0
+.Ldebug_loclist_table_start0:
+ .short 5 # Version.
+ .byte 8 # Address size.
+ .byte 0 # Segment selector size.
+ .long 0 # Offset entry count.
+.Lloclists_table_base0:
+.Ldebug_loc0:
+.ifdef CASE1
+ .byte 4 # DW_LLE_offset_pair
+.endif
+.ifdef CASE2
+ .byte 4 # DW_LLE_offset_pair
+ .uleb128 0x0 # starting offset
+.endif
+.ifdef CASE3
+ .byte 4 # DW_LLE_offset_pair
+ .uleb128 0x0 # starting offset
+ .uleb128 0x10 # ending offset
+.endif
+.ifdef CASE4
+ .byte 4 # DW_LLE_offset_pair
+ .uleb128 0x0 # starting offset
+ .uleb128 0x10 # ending offset
+ .byte 1 # Loc expr size
+.endif
+.ifdef CASE5
+ .byte 4 # DW_LLE_offset_pair
+ .uleb128 0x0 # starting offset
+ .uleb128 0x10 # ending offset
+ .byte 1 # Loc expr size
+ .byte 117 # DW_OP_breg5
+.endif
+.ifdef CASE6
+ .byte 4 # DW_LLE_offset_pair
+ .uleb128 0x0 # starting offset
+ .uleb128 0x10 # ending offset
+ .uleb128 0xdeadbeef # Loc expr size
+.endif
+.ifdef CASE7
+ .byte 0x47
+.endif
+
+.Ldebug_loclist_table_end0:
+
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