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[DWARF] Emit DW_AT_call_return_pc as an address

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This reverts D53469, which changed llvm's DWARF emission to emit
DW_AT_call_return_pc as a function-local offset. Such an encoding is not
compatible with post-link block re-ordering tools and isn't standards-
compliant.

In addition to reverting back to the original DW_AT_call_return_pc
encoding, teach lldb how to fix up DW_AT_call_return_pc when the address
comes from an object file pointed-to by a debug map. While doing this I
noticed that lldb's support for tail calls that cross a DSO/object file
boundary wasn't covered, so I added tests for that. This latter case
exercises the newly added return PC fixup.

The dsymutil changes in this patch were originally included in D49887:
the associated test should be sufficient to test DW_AT_call_return_pc
encoding purely on the llvm side.

Differential Revision: https://reviews.llvm.org/D72489
This commit is contained in:
Vedant Kumar
2020-01-09 18:00:33 -08:00
parent d629525597
commit f0120556c7
29 changed files with 338 additions and 68 deletions
Download Patch File Download Diff File Expand all files Collapse all files

8
lldb/include/lldb/Symbol/Function.h
View File

@@ -281,8 +281,7 @@ public:
/// made the call.
lldb::addr_t GetReturnPCAddress(Function &caller, Target &target) const;
/// Like \ref GetReturnPCAddress, but returns an unslid function-local PC
/// offset.
/// Like \ref GetReturnPCAddress, but returns an unresolved file address.
lldb::addr_t GetUnresolvedReturnPCAddress() const { return return_pc; }
/// Get the call site parameters available at this call edge.
@@ -294,9 +293,8 @@ protected:
CallEdge(lldb::addr_t return_pc, CallSiteParameterArray &&parameters)
: return_pc(return_pc), parameters(std::move(parameters)) {}
/// An invalid address if this is a tail call. Otherwise, the function-local
/// PC offset. Adding this PC offset to the function's base load address
/// gives the return PC for the call.
/// An invalid address if this is a tail call. Otherwise, the return PC for
/// the call. Note that this is a file address which must be resolved.
lldb::addr_t return_pc;
CallSiteParameterArray parameters;

17
lldb/packages/Python/lldbsuite/test/functionalities/tail_call_frames/cross_dso/Makefile Normal file
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@@ -0,0 +1,17 @@
LD_EXTRAS := -L. -l$(LIB_PREFIX)One -l$(LIB_PREFIX)Two
C_SOURCES := main.c
CFLAGS_EXTRAS := -g -O2 -glldb
include Makefile.rules
.PHONY:
a.out: lib_One lib_Two
lib_One: lib_Two
lib_%:
$(MAKE) VPATH=$(SRCDIR)/$* -I $(SRCDIR) -f $(SRCDIR)/$*.mk DSYMUTIL=$(DSYMUTIL)
clean::
$(MAKE) -f $(SRCDIR)/One.mk clean
$(MAKE) -f $(SRCDIR)/Two.mk clean

7
lldb/packages/Python/lldbsuite/test/functionalities/tail_call_frames/cross_dso/One.mk Normal file
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@@ -0,0 +1,7 @@
DYLIB_NAME := One
DYLIB_C_SOURCES := One.c
DYLIB_ONLY := YES
CFLAGS_EXTRAS := -g -O2 -glldb
LD_EXTRAS := -L. -lTwo
include Makefile.rules

11
lldb/packages/Python/lldbsuite/test/functionalities/tail_call_frames/cross_dso/One/One.c Normal file
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@@ -0,0 +1,11 @@
#include "shared.h"
__attribute__((noinline))
static void helper_in_a() {
tail_called_in_b_from_a();
}
__attribute__((disable_tail_calls))
void tail_called_in_a_from_main() {
helper_in_a();
}

64
lldb/packages/Python/lldbsuite/test/functionalities/tail_call_frames/cross_dso/TestCrossDSOTailCalls.py Normal file
View File

@@ -0,0 +1,64 @@
"""Test that backtraces can follow cross-DSO tail calls"""
import lldb
from lldbsuite.test.decorators import *
from lldbsuite.test.lldbtest import *
from lldbsuite.test import lldbutil
class TestCrossDSOTailCalls(TestBase):
mydir = TestBase.compute_mydir(__file__)
def setUp(self):
TestBase.setUp(self)
@skipIf(compiler="clang", compiler_version=['<', '8.0'])
@skipIf(dwarf_version=['<', '4'])
@expectedFailureAll(oslist=["windows"], bugnumber="llvm.org/pr26265")
def test_cross_dso_tail_calls(self):
self.build()
exe = self.getBuildArtifact("a.out")
target = self.dbg.CreateTarget(exe)
self.assertTrue(target, VALID_TARGET)
# Register our shared libraries for remote targets so they get
# automatically uploaded
environment = self.registerSharedLibrariesWithTarget(
target, ['One', 'Two'])
lldbutil.run_break_set_by_source_regexp(self, '// break here',
extra_options='-f Two.c')
process = target.LaunchSimple(
None, environment, self.get_process_working_directory())
self.assertTrue(process, PROCESS_IS_VALID)
# We should be stopped in the second dylib.
thread = lldbutil.get_stopped_thread(process, lldb.eStopReasonBreakpoint)
# Debug helper:
# self.runCmd("log enable -f /tmp/lldb.log lldb step")
# self.runCmd("bt")
# Check that the backtrace is what we expect:
# frame #0: 0x000000010d5e5f94 libTwo.dylib`tail_called_in_b_from_b at Two.c:7:3 [opt]
# frame #1: 0x000000010d5e5fa0 libTwo.dylib`tail_called_in_b_from_a [opt] [artificial]
# frame #2: 0x000000010d5dcf80 libOne.dylib`helper_in_a [opt] [artificial]
# frame #3: 0x000000010d5dcf79 libOne.dylib`tail_called_in_a_from_main at One.c:10:3 [opt]
# frame #4: 0x000000010d5d3f80 a.out`helper [opt] [artificial]
# frame #5: 0x000000010d5d3f79 a.out`main at main.c:10:3 [opt]
expected_frames = [
("tail_called_in_b_from_b", False),
("tail_called_in_b_from_a", True),
("helper_in_a", True),
("tail_called_in_a_from_main", False),
("helper", True),
("main", False)
]
for idx, (name, is_artificial) in enumerate(expected_frames):
frame = thread.GetFrameAtIndex(idx)
self.assertTrue(name in frame.GetDisplayFunctionName())
self.assertEqual(frame.IsArtificial(), is_artificial)

6
lldb/packages/Python/lldbsuite/test/functionalities/tail_call_frames/cross_dso/Two.mk Normal file
View File

@@ -0,0 +1,6 @@
DYLIB_NAME := Two
DYLIB_C_SOURCES := Two.c
DYLIB_ONLY := YES
CFLAGS_EXTRAS := -g -O2 -glldb
include Makefile.rules

12
lldb/packages/Python/lldbsuite/test/functionalities/tail_call_frames/cross_dso/Two/Two.c Normal file
View File

@@ -0,0 +1,12 @@
#include "shared.h"
volatile int x;
__attribute__((noinline))
void tail_called_in_b_from_b() {
++x; // break here
}
void tail_called_in_b_from_a() {
tail_called_in_b_from_b();
}

12
lldb/packages/Python/lldbsuite/test/functionalities/tail_call_frames/cross_dso/main.c Normal file
View File

@@ -0,0 +1,12 @@
#include "shared.h"
__attribute__((noinline))
static void helper() {
tail_called_in_a_from_main();
}
__attribute__((disable_tail_calls))
int main() {
helper();
return 0;
}

3
lldb/packages/Python/lldbsuite/test/functionalities/tail_call_frames/cross_dso/shared.h Normal file
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@@ -0,0 +1,3 @@
void tail_called_in_a_from_main();
void tail_called_in_b_from_a();

4
lldb/packages/Python/lldbsuite/test/functionalities/tail_call_frames/cross_object/Makefile Normal file
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@@ -0,0 +1,4 @@
C_SOURCES := main.c One.c Two.c
CFLAGS_EXTRAS := -g -O2 -glldb
include Makefile.rules

11
lldb/packages/Python/lldbsuite/test/functionalities/tail_call_frames/cross_object/One.c Normal file
View File

@@ -0,0 +1,11 @@
#include "shared.h"
__attribute__((noinline))
static void helper_in_a() {
tail_called_in_b_from_a();
}
__attribute__((disable_tail_calls))
void tail_called_in_a_from_main() {
helper_in_a();
}

59
lldb/packages/Python/lldbsuite/test/functionalities/tail_call_frames/cross_object/TestCrossObjectTailCalls.py Normal file
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@@ -0,0 +1,59 @@
"""Test that backtraces can follow cross-object tail calls"""
import lldb
from lldbsuite.test.decorators import *
from lldbsuite.test.lldbtest import *
from lldbsuite.test import lldbutil
class TestCrossObjectTailCalls(TestBase):
mydir = TestBase.compute_mydir(__file__)
def setUp(self):
TestBase.setUp(self)
@skipIf(compiler="clang", compiler_version=['<', '8.0'])
@skipIf(dwarf_version=['<', '4'])
@expectedFailureAll(oslist=["windows"], bugnumber="llvm.org/pr26265")
def test_cross_object_tail_calls(self):
self.build()
exe = self.getBuildArtifact("a.out")
target = self.dbg.CreateTarget(exe)
self.assertTrue(target, VALID_TARGET)
lldbutil.run_break_set_by_source_regexp(self, '// break here',
extra_options='-f Two.c')
process = target.LaunchSimple(
None, None, self.get_process_working_directory())
self.assertTrue(process, PROCESS_IS_VALID)
# We should be stopped in the second dylib.
thread = lldbutil.get_stopped_thread(process, lldb.eStopReasonBreakpoint)
# Debug helper:
# self.runCmd("log enable -f /tmp/lldb.log lldb step")
# self.runCmd("bt")
# Check that the backtrace is what we expect:
# frame #0: 0x000000010be73f94 a.out`tail_called_in_b_from_b at Two.c:7:3 [opt]
# frame #1: 0x000000010be73fa0 a.out`tail_called_in_b_from_a at Two.c:8:1 [opt] [artificial]
# frame #2: 0x000000010be73f80 a.out`helper_in_a at One.c:11:1 [opt] [artificial]
# frame #3: 0x000000010be73f79 a.out`tail_called_in_a_from_main at One.c:10:3 [opt]
# frame #4: 0x000000010be73f60 a.out`helper at main.c:11:3 [opt] [artificial]
# frame #5: 0x000000010be73f59 a.out`main at main.c:10:3 [opt]
expected_frames = [
("tail_called_in_b_from_b", False),
("tail_called_in_b_from_a", True),
("helper_in_a", True),
("tail_called_in_a_from_main", False),
("helper", True),
("main", False)
]
for idx, (name, is_artificial) in enumerate(expected_frames):
frame = thread.GetFrameAtIndex(idx)
self.assertTrue(name in frame.GetDisplayFunctionName())
self.assertEqual(frame.IsArtificial(), is_artificial)

12
lldb/packages/Python/lldbsuite/test/functionalities/tail_call_frames/cross_object/Two.c Normal file
View File

@@ -0,0 +1,12 @@
#include "shared.h"
volatile int x;
__attribute__((noinline))
void tail_called_in_b_from_b() {
++x; // break here
}
void tail_called_in_b_from_a() {
tail_called_in_b_from_b();
}

12
lldb/packages/Python/lldbsuite/test/functionalities/tail_call_frames/cross_object/main.c Normal file
View File

@@ -0,0 +1,12 @@
#include "shared.h"
__attribute__((noinline))
static void helper() {
tail_called_in_a_from_main();
}
__attribute__((disable_tail_calls))
int main() {
helper();
return 0;
}

3
lldb/packages/Python/lldbsuite/test/functionalities/tail_call_frames/cross_object/shared.h Normal file
View File

@@ -0,0 +1,3 @@
void tail_called_in_a_from_main();
void tail_called_in_b_from_a();

16
lldb/source/Plugins/SymbolFile/DWARF/SymbolFileDWARF.cpp
View File

@@ -792,6 +792,13 @@ Function *SymbolFileDWARF::ParseFunction(CompileUnit &comp_unit,
return dwarf_ast->ParseFunctionFromDWARF(comp_unit, die);
}
lldb::addr_t SymbolFileDWARF::FixupAddress(lldb::addr_t file_addr) {
SymbolFileDWARFDebugMap *debug_map_symfile = GetDebugMapSymfile();
if (debug_map_symfile)
return debug_map_symfile->LinkOSOFileAddress(this, file_addr);
return file_addr;
}
bool SymbolFileDWARF::FixupAddress(Address &addr) {
SymbolFileDWARFDebugMap *debug_map_symfile = GetDebugMapSymfile();
if (debug_map_symfile) {
@@ -3805,8 +3812,8 @@ CollectCallSiteParameters(ModuleSP module, DWARFDIE call_site_die) {
}
/// Collect call graph edges present in a function DIE.
static std::vector<std::unique_ptr<lldb_private::CallEdge>>
CollectCallEdges(ModuleSP module, DWARFDIE function_die) {
std::vector<std::unique_ptr<lldb_private::CallEdge>>
SymbolFileDWARF::CollectCallEdges(ModuleSP module, DWARFDIE function_die) {
// Check if the function has a supported call site-related attribute.
// TODO: In the future it may be worthwhile to support call_all_source_calls.
uint64_t has_call_edges =
@@ -3882,6 +3889,11 @@ CollectCallEdges(ModuleSP module, DWARFDIE function_die) {
continue;
}
// Adjust the return PC. It needs to be fixed up if the main executable
// contains a debug map (i.e. pointers to object files), because we need a
// file address relative to the executable's text section.
return_pc = FixupAddress(return_pc);
// Extract call site parameters.
CallSiteParameterArray parameters =
CollectCallSiteParameters(module, child);

12
lldb/source/Plugins/SymbolFile/DWARF/SymbolFileDWARF.h
View File

@@ -417,6 +417,18 @@ protected:
bool ClassContainsSelector(const DWARFDIE &class_die,
lldb_private::ConstString selector);
/// Parse call site entries (DW_TAG_call_site), including any nested call site
/// parameters (DW_TAG_call_site_parameter).
std::vector<std::unique_ptr<lldb_private::CallEdge>>
CollectCallEdges(lldb::ModuleSP module, DWARFDIE function_die);
/// If this symbol file is linked to by a debug map (see
/// SymbolFileDWARFDebugMap), and \p file_addr is a file address relative to
/// an object file, adjust \p file_addr so that it is relative to the main
/// binary. Returns the adjusted address, or \p file_addr if no adjustment is
/// needed, on success and LLDB_INVALID_ADDRESS otherwise.
lldb::addr_t FixupAddress(lldb::addr_t file_addr);
bool FixupAddress(lldb_private::Address &addr);
typedef std::set<lldb_private::Type *> TypeSet;

21
lldb/source/Symbol/Function.cpp
View File

@@ -123,8 +123,25 @@ size_t InlineFunctionInfo::MemorySize() const {
lldb::addr_t CallEdge::GetReturnPCAddress(Function &caller,
Target &target) const {
const Address &base = caller.GetAddressRange().GetBaseAddress();
return base.GetLoadAddress(&target) + return_pc;
Log *log(lldb_private::GetLogIfAllCategoriesSet(LIBLLDB_LOG_STEP));
const Address &caller_start_addr = caller.GetAddressRange().GetBaseAddress();
ModuleSP caller_module_sp = caller_start_addr.GetModule();
if (!caller_module_sp) {
LLDB_LOG(log, "GetReturnPCAddress: cannot get Module for caller");
return LLDB_INVALID_ADDRESS;
}
SectionList *section_list = caller_module_sp->GetSectionList();
if (!section_list) {
LLDB_LOG(log, "GetReturnPCAddress: cannot get SectionList for Module");
return LLDB_INVALID_ADDRESS;
}
Address return_pc_addr = Address(return_pc, section_list);
lldb::addr_t ret_addr = return_pc_addr.GetLoadAddress(&target);
return ret_addr;
}
void DirectCallEdge::ParseSymbolFileAndResolve(ModuleList &images) {

4
llvm/include/llvm/CodeGen/DebugHandlerBase.h
View File

@@ -124,10 +124,6 @@ public:
/// Return Label immediately following the instruction.
MCSymbol *getLabelAfterInsn(const MachineInstr *MI);
/// Return the function-local offset of an instruction. A label for the
/// instruction \p MI should exist (\ref getLabelAfterInsn).
const MCExpr *getFunctionLocalOffsetAfterInsn(const MachineInstr *MI);
/// If this type is derived from a base type then return base type size.
static uint64_t getBaseTypeSize(const DIType *Ty);
};

15
llvm/lib/CodeGen/AsmPrinter/DebugHandlerBase.cpp
View File

@@ -124,21 +124,6 @@ MCSymbol *DebugHandlerBase::getLabelAfterInsn(const MachineInstr *MI) {
return LabelsAfterInsn.lookup(MI);
}
// Return the function-local offset of an instruction.
const MCExpr *
DebugHandlerBase::getFunctionLocalOffsetAfterInsn(const MachineInstr *MI) {
MCContext &MC = Asm->OutContext;
MCSymbol *Start = Asm->getFunctionBegin();
const auto *StartRef = MCSymbolRefExpr::create(Start, MC);
MCSymbol *AfterInsn = getLabelAfterInsn(MI);
assert(AfterInsn && "Expected label after instruction");
const auto *AfterRef = MCSymbolRefExpr::create(AfterInsn, MC);
return MCBinaryExpr::createSub(AfterRef, StartRef, MC);
}
/// If this type is derived from a base type then return base type size.
uint64_t DebugHandlerBase::getBaseTypeSize(const DIType *Ty) {
assert(Ty);

18
llvm/lib/CodeGen/AsmPrinter/DwarfCompileUnit.cpp
View File

@@ -956,9 +956,11 @@ DwarfCompileUnit::getDwarf5OrGNULocationAtom(dwarf::LocationAtom Loc) const {
}
}
DIE &DwarfCompileUnit::constructCallSiteEntryDIE(
DIE &ScopeDIE, const DISubprogram *CalleeSP, bool IsTail,
const MCSymbol *PCAddr, const MCExpr *PCOffset, unsigned CallReg) {
DIE &DwarfCompileUnit::constructCallSiteEntryDIE(DIE &ScopeDIE,
const DISubprogram *CalleeSP,
bool IsTail,
const MCSymbol *PCAddr,
unsigned CallReg) {
// Insert a call site entry DIE within ScopeDIE.
DIE &CallSiteDIE = createAndAddDIE(getDwarf5OrGNUTag(dwarf::DW_TAG_call_site),
ScopeDIE, nullptr);
@@ -984,8 +986,8 @@ DIE &DwarfCompileUnit::constructCallSiteEntryDIE(
assert(PCAddr && "Missing PC information for a call");
addLabelAddress(CallSiteDIE, dwarf::DW_AT_low_pc, PCAddr);
} else if (!IsTail || DD->tuneForGDB()) {
assert(PCOffset && "Missing return PC information for a call");
addAddressExpr(CallSiteDIE, dwarf::DW_AT_call_return_pc, PCOffset);
assert(PCAddr && "Missing return PC information for a call");
addLabelAddress(CallSiteDIE, dwarf::DW_AT_call_return_pc, PCAddr);
}
return CallSiteDIE;
@@ -1285,12 +1287,6 @@ void DwarfCompileUnit::addExpr(DIELoc &Die, dwarf::Form Form,
Die.addValue(DIEValueAllocator, (dwarf::Attribute)0, Form, DIEExpr(Expr));
}
void DwarfCompileUnit::addAddressExpr(DIE &Die, dwarf::Attribute Attribute,
const MCExpr *Expr) {
Die.addValue(DIEValueAllocator, Attribute, dwarf::DW_FORM_addr,
DIEExpr(Expr));
}
void DwarfCompileUnit::applySubprogramAttributesToDefinition(
const DISubprogram *SP, DIE &SPDie) {
auto *SPDecl = SP->getDeclaration();

12
llvm/lib/CodeGen/AsmPrinter/DwarfCompileUnit.h
View File

@@ -242,17 +242,12 @@ public:
/// Construct a call site entry DIE describing a call within \p Scope to a
/// callee described by \p CalleeSP.
/// \p IsTail specifies whether the call is a tail call.
/// \p PCAddr (used for GDB + DWARF 4 tuning) points to the PC value after
/// the call instruction.
/// \p PCOffset (used for cases other than GDB + DWARF 4 tuning) must be
/// non-zero for non-tail calls (in the case of non-gdb tuning, since for
/// GDB + DWARF 5 tuning we still generate PC info for tail calls) or be the
/// function-local offset to PC value after the call instruction.
/// \p PCAddr points to the PC value after the call instruction.
/// \p CallReg is a register location for an indirect call. For direct calls
/// the \p CallReg is set to 0.
DIE &constructCallSiteEntryDIE(DIE &ScopeDIE, const DISubprogram *CalleeSP,
bool IsTail, const MCSymbol *PCAddr,
const MCExpr *PCOffset, unsigned CallReg);
unsigned CallReg);
/// Construct call site parameter DIEs for the \p CallSiteDIE. The \p Params
/// were collected by the \ref collectCallSiteParameters.
/// Note: The order of parameters does not matter, since debuggers recognize
@@ -340,9 +335,6 @@ public:
/// Add a Dwarf expression attribute data and value.
void addExpr(DIELoc &Die, dwarf::Form Form, const MCExpr *Expr);
/// Add an attribute containing an address expression to \p Die.
void addAddressExpr(DIE &Die, dwarf::Attribute Attribute, const MCExpr *Expr);
void applySubprogramAttributesToDefinition(const DISubprogram *SP,
DIE &SPDie);

23
llvm/lib/CodeGen/AsmPrinter/DwarfDebug.cpp
View File

@@ -719,7 +719,6 @@ void DwarfDebug::constructCallSiteEntryDIEs(const DISubprogram &SP,
const TargetInstrInfo *TII = MF.getSubtarget().getInstrInfo();
assert(TII && "TargetInstrInfo not found: cannot label tail calls");
bool ApplyGNUExtensions = getDwarfVersion() == 4 && tuneForGDB();
// Emit call site entries for each call or tail call in the function.
for (const MachineBasicBlock &MBB : MF) {
@@ -781,25 +780,16 @@ void DwarfDebug::constructCallSiteEntryDIEs(const DISubprogram &SP,
const MachineInstr *TopLevelCallMI =
MI.isInsideBundle() ? &*getBundleStart(MI.getIterator()) : &MI;
// For tail calls, for non-gdb tuning, no return PC information is needed.
// For tail calls, no return PC information is needed.
// For regular calls (and tail calls in GDB tuning), the return PC
// is needed to disambiguate paths in the call graph which could lead to
// some target function.
const MCExpr *PCOffset =
const MCSymbol *PCAddr =
(IsTail && !tuneForGDB())
? nullptr
: getFunctionLocalOffsetAfterInsn(TopLevelCallMI);
: const_cast<MCSymbol *>(getLabelAfterInsn(TopLevelCallMI));
// Return address of a call-like instruction for a normal call or a
// jump-like instruction for a tail call. This is needed for
// GDB + DWARF 4 tuning.
const MCSymbol *PCAddr =
ApplyGNUExtensions
? const_cast<MCSymbol *>(getLabelAfterInsn(TopLevelCallMI))
: nullptr;
assert((IsTail || PCOffset || PCAddr) &&
"Call without return PC information");
assert((IsTail || PCAddr) && "Call without return PC information");
LLVM_DEBUG(dbgs() << "CallSiteEntry: " << MF.getName() << " -> "
<< (CalleeDecl ? CalleeDecl->getName()
@@ -808,9 +798,8 @@ void DwarfDebug::constructCallSiteEntryDIEs(const DISubprogram &SP,
->getName(CallReg)))
<< (IsTail ? " [IsTail]" : "") << "\n");
DIE &CallSiteDIE =
CU.constructCallSiteEntryDIE(ScopeDIE, CalleeSP, IsTail, PCAddr,
PCOffset, CallReg);
DIE &CallSiteDIE = CU.constructCallSiteEntryDIE(ScopeDIE, CalleeSP,
IsTail, PCAddr, CallReg);
// GDB and LLDB support call site parameter debug info.
if (Asm->TM.Options.EnableDebugEntryValues &&

11
llvm/test/DebugInfo/X86/debug_addr.ll
View File

@@ -9,6 +9,7 @@
; }
;
; void bar() {
; foo();
; }
; DWARF4: .debug_info contents:
@@ -18,11 +19,14 @@
; DWARF4-NOT: DW_TAG_{{.*}}
; DWARF4: DW_AT_GNU_dwo_name{{.*}}test.dwo
; DWARF4: DW_AT_GNU_addr_base{{.*}}0x00000000
; DWARF4: DW_TAG_GNU_call_site
; DWARF4: DW_AT_low_pc [DW_FORM_GNU_addr_index] (indexed (00000002) address = 0x0000000000000018 ".text")
; DWARF4: .debug_addr contents:
; DWARF4-NEXT: 0x00000000: Addr Section: length = 0x00000000, version = 0x0004, addr_size = 0x04, seg_size = 0x00
; DWARF4-NEXT: Addrs: [
; DWARF4-NEXT: 0x00000000
; DWARF4-NEXT: 0x00000010
; DWARF4-NEXT: 0x00000018
; DWARF4-NEXT: ]
; DWARF5: .debug_info contents:
@@ -33,11 +37,13 @@
; DWARF5: DW_AT_dwo_name{{.*}}test.dwo
; DWARF5: DW_AT_addr_base{{.*}}0x00000008
; DWARF5: DW_AT_low_pc [DW_FORM_addrx] (indexed (00000000) address = 0x0000000000000000 ".text")
; DWARF5: DW_AT_call_return_pc [DW_FORM_addrx] (indexed (00000002) address = 0x0000000000000018 ".text")
; DWARF5: .debug_addr contents:
; DWARF5-NEXT: 0x00000000: Addr Section: length = 0x0000000c, version = 0x0005, addr_size = 0x04, seg_size = 0x00
; DWARF5-NEXT: 0x00000000: Addr Section: length = 0x00000010, version = 0x0005, addr_size = 0x04, seg_size = 0x00
; DWARF5-NEXT: Addrs: [
; DWARF5-NEXT: 0x00000000
; DWARF5-NEXT: 0x00000010
; DWARF5-NEXT: 0x00000018
; DWARF5-NEXT: ]
; ModuleID = './test.c'
@@ -54,6 +60,7 @@ entry:
; Function Attrs: noinline nounwind optnone
define void @bar() #0 !dbg !13 {
entry:
call void @foo(), !dbg !14
ret void, !dbg !14
}
@@ -76,5 +83,5 @@ attributes #0 = { noinline nounwind optnone }
!10 = !DISubroutineType(types: !11)
!11 = !{null}
!12 = !DILocation(line: 2, column: 3, scope: !8)
!13 = distinct !DISubprogram(name: "bar", scope: !9, file: !9, line: 5, type: !10, isLocal: false, isDefinition: true, scopeLine: 5, isOptimized: false, unit: !0)
!13 = distinct !DISubprogram(name: "bar", scope: !9, file: !9, line: 5, type: !10, isLocal: false, isDefinition: true, flags: DIFlagAllCallsDescribed, scopeLine: 5, isOptimized: false, unit: !0)
!14 = !DILocation(line: 6, column: 3, scope: !13)

25
llvm/test/tools/dsymutil/Inputs/call-site-entry.c Normal file
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@@ -0,0 +1,25 @@
/*
* This file is used to test dsymutil support for call site entries
* (DW_TAG_call_site / DW_AT_call_return_pc).
*
* Instructions for regenerating binaries (on Darwin/x86_64):
*
* 1. Copy the source to a top-level directory to work around having absolute
* paths in the symtab's OSO entries.
*
* mkdir -p /Inputs/ && cp call-site-entry.c /Inputs && cd /Inputs
*
* 2. Compile with call site info enabled.
*
* clang -g -O1 -Xclang -disable-llvm-passes call-site-entry.c -c -o call-site-entry.macho.x86_64.o
* clang call-site-entry.macho.x86_64.o -o call-site-entry.macho.x86_64
*
* 3. Copy the binaries back into the repo's Inputs directory. You'll need
* -oso-prepend-path=%p to link.
*/
__attribute__((optnone)) int f() {}
int main() {
f();
}

BIN
llvm/test/tools/dsymutil/Inputs/call-site-entry.macho.x86_64 Executable file
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Binary file not shown.

BIN
llvm/test/tools/dsymutil/Inputs/call-site-entry.macho.x86_64.o Normal file
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Binary file not shown.

4
llvm/test/tools/dsymutil/call-site-entry-linking.test Normal file
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@@ -0,0 +1,4 @@
RUN: dsymutil -oso-prepend-path=%p %p/Inputs/call-site-entry.macho.x86_64 -o %t.dSYM
RUN: llvm-dwarfdump %t.dSYM | FileCheck %s -implicit-check-not=DW_AT_call_return_pc
CHECK: DW_AT_call_return_pc (0x0000000100000fa4)

4
llvm/tools/dsymutil/DwarfLinkerForBinary.cpp
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@@ -1363,6 +1363,10 @@ unsigned DwarfLinkerForBinary::DIECloner::cloneAddressAttribute(
// it. Otherwise (when no relocations where applied) just use the
// one we just decoded.
Addr = (Info.OrigHighPc ? Info.OrigHighPc : Addr) + Info.PCOffset;
} else if (AttrSpec.Attr == dwarf::DW_AT_call_return_pc) {
// Relocate a return PC address within a call site entry.
if (Die.getTag() == dwarf::DW_TAG_call_site)
Addr += Info.PCOffset;
}
Die.addValue(DIEAlloc, static_cast<dwarf::Attribute>(AttrSpec.Attr),