[Lldb-commits] [lldb] r374342 - Fix the unwinding plan augmentation from x86 assembly
Pavel Labath via lldb-commits
lldb-commits at lists.llvm.org
Thu Oct 10 06:23:09 PDT 2019
Author: labath
Date: Thu Oct 10 06:23:09 2019
New Revision: 374342
URL: http://llvm.org/viewvc/llvm-project?rev=374342&view=rev
Log:
Fix the unwinding plan augmentation from x86 assembly
Unwind plan augmentation should compute the plan row at offset x from
the instruction before offset x, but currently we compute it from the
instruction at offset x. Note that this behavior is a regression
introduced when moving the x86 assembly inspection engine to its own
file
(https://github.com/llvm/llvm-project/commit/1c9858b298d79ce82c45a2954096718b39550109#diff-375a2be066db6f34bb9a71442c9b71fcL913);
the original version handled this properly by copying the previous
instruction out before advancing the instruction pointer.
The relevant bug with more info is here: https://bugs.llvm.org/show_bug.cgi?id=43561
Differential Revision: https://reviews.llvm.org/D68454
Patch by Jaroslav Sevcik <jarin at google.com>.
Modified:
lldb/trunk/source/Plugins/UnwindAssembly/x86/x86AssemblyInspectionEngine.cpp
lldb/trunk/unittests/UnwindAssembly/x86/Testx86AssemblyInspectionEngine.cpp
Modified: lldb/trunk/source/Plugins/UnwindAssembly/x86/x86AssemblyInspectionEngine.cpp
URL: http://llvm.org/viewvc/llvm-project/lldb/trunk/source/Plugins/UnwindAssembly/x86/x86AssemblyInspectionEngine.cpp?rev=374342&r1=374341&r2=374342&view=diff
==============================================================================
--- lldb/trunk/source/Plugins/UnwindAssembly/x86/x86AssemblyInspectionEngine.cpp (original)
+++ lldb/trunk/source/Plugins/UnwindAssembly/x86/x86AssemblyInspectionEngine.cpp Thu Oct 10 06:23:09 2019
@@ -1371,7 +1371,6 @@ bool x86AssemblyInspectionEngine::Augmen
int row_id = 1;
bool unwind_plan_updated = false;
UnwindPlan::RowSP row(new UnwindPlan::Row(*first_row));
- m_cur_insn = data + offset;
// After a mid-function epilogue we will need to re-insert the original
// unwind rules so unwinds work for the remainder of the function. These
@@ -1381,19 +1380,17 @@ bool x86AssemblyInspectionEngine::Augmen
while (offset < size) {
m_cur_insn = data + offset;
int insn_len;
- if (!instruction_length(m_cur_insn, insn_len, size - offset)
- || insn_len == 0
- || insn_len > kMaxInstructionByteSize) {
+ if (!instruction_length(m_cur_insn, insn_len, size - offset) ||
+ insn_len == 0 || insn_len > kMaxInstructionByteSize) {
// An unrecognized/junk instruction.
break;
}
// Advance offsets.
offset += insn_len;
- m_cur_insn = data + offset;
// offset is pointing beyond the bounds of the function; stop looping.
- if (offset >= size)
+ if (offset >= size)
continue;
if (reinstate_unwind_state) {
@@ -1547,16 +1544,18 @@ bool x86AssemblyInspectionEngine::Augmen
// [0x5d] pop %rbp/%ebp
// => [0xc3] ret
if (pop_rbp_pattern_p() || leave_pattern_p()) {
- offset += 1;
- row->SetOffset(offset);
- row->GetCFAValue().SetIsRegisterPlusOffset(
- first_row->GetCFAValue().GetRegisterNumber(), m_wordsize);
-
- UnwindPlan::RowSP new_row(new UnwindPlan::Row(*row));
- unwind_plan.InsertRow(new_row);
- unwind_plan_updated = true;
- reinstate_unwind_state = true;
- continue;
+ m_cur_insn++;
+ if (ret_pattern_p()) {
+ row->SetOffset(offset);
+ row->GetCFAValue().SetIsRegisterPlusOffset(
+ first_row->GetCFAValue().GetRegisterNumber(), m_wordsize);
+
+ UnwindPlan::RowSP new_row(new UnwindPlan::Row(*row));
+ unwind_plan.InsertRow(new_row);
+ unwind_plan_updated = true;
+ reinstate_unwind_state = true;
+ continue;
+ }
}
} else {
// CFA register is not sp or fp.
Modified: lldb/trunk/unittests/UnwindAssembly/x86/Testx86AssemblyInspectionEngine.cpp
URL: http://llvm.org/viewvc/llvm-project/lldb/trunk/unittests/UnwindAssembly/x86/Testx86AssemblyInspectionEngine.cpp?rev=374342&r1=374341&r2=374342&view=diff
==============================================================================
--- lldb/trunk/unittests/UnwindAssembly/x86/Testx86AssemblyInspectionEngine.cpp (original)
+++ lldb/trunk/unittests/UnwindAssembly/x86/Testx86AssemblyInspectionEngine.cpp Thu Oct 10 06:23:09 2019
@@ -2199,6 +2199,97 @@ TEST_F(Testx86AssemblyInspectionEngine,
EXPECT_EQ(-40, regloc.GetOffset());
}
+TEST_F(Testx86AssemblyInspectionEngine, TestSpArithx86_64Augmented) {
+ UnwindPlan::Row::RegisterLocation regloc;
+ UnwindPlan::RowSP row_sp;
+ AddressRange sample_range;
+ UnwindPlan unwind_plan(eRegisterKindLLDB);
+ std::unique_ptr<x86AssemblyInspectionEngine> engine64 = Getx86_64Inspector();
+
+ uint8_t data[] = {
+ 0x55, // pushq %rbp
+ 0x48, 0x89, 0xe5, // movq %rsp, %rbp
+
+ // x86AssemblyInspectionEngine::AugmentUnwindPlanFromCallSite
+ // has a bug where it can't augment a function that is just
+ // prologue+epilogue - it needs at least one other instruction
+ // in between.
+
+ 0x90, // nop
+ 0x48, 0x81, 0xec, 0x88, 0, 0, 0, // subq $0x88, %rsp
+ 0x90, // nop
+ 0x48, 0x81, 0xc4, 0x88, 0, 0, 0, // addq $0x88, %rsp
+
+ 0x5d, // popq %rbp
+ 0xc3 // retq
+ };
+
+ sample_range = AddressRange(0x1000, sizeof(data));
+
+ unwind_plan.SetSourceName("unit testing hand-created unwind plan");
+ unwind_plan.SetPlanValidAddressRange(sample_range);
+ unwind_plan.SetRegisterKind(eRegisterKindLLDB);
+
+ row_sp = std::make_shared<UnwindPlan::Row>();
+
+ // Describe offset 0
+ row_sp->SetOffset(0);
+ row_sp->GetCFAValue().SetIsRegisterPlusOffset(k_rsp, 8);
+
+ regloc.SetAtCFAPlusOffset(-8);
+ row_sp->SetRegisterInfo(k_rip, regloc);
+
+ unwind_plan.AppendRow(row_sp);
+
+ // Allocate a new Row, populate it with the existing Row contents.
+ UnwindPlan::Row *new_row = new UnwindPlan::Row;
+ *new_row = *row_sp.get();
+ row_sp.reset(new_row);
+
+ // Describe offset 1
+ row_sp->SetOffset(1);
+ row_sp->GetCFAValue().SetIsRegisterPlusOffset(k_rsp, 16);
+ regloc.SetAtCFAPlusOffset(-16);
+ row_sp->SetRegisterInfo(k_rbp, regloc);
+ unwind_plan.AppendRow(row_sp);
+
+ // Allocate a new Row, populate it with the existing Row contents.
+ new_row = new UnwindPlan::Row;
+ *new_row = *row_sp.get();
+ row_sp.reset(new_row);
+
+ // Describe offset 4
+ row_sp->SetOffset(4);
+ row_sp->GetCFAValue().SetIsRegisterPlusOffset(k_rsp, 16);
+ unwind_plan.AppendRow(row_sp);
+
+ RegisterContextSP reg_ctx_sp;
+ EXPECT_TRUE(engine64->AugmentUnwindPlanFromCallSite(
+ data, sizeof(data), sample_range, unwind_plan, reg_ctx_sp));
+
+ // Before we touch the stack pointer, we should still refer to the
+ // row from after the prologue.
+ row_sp = unwind_plan.GetRowForFunctionOffset(5);
+ EXPECT_EQ(4ull, row_sp->GetOffset());
+
+ // Check the first stack pointer update.
+ row_sp = unwind_plan.GetRowForFunctionOffset(12);
+ EXPECT_EQ(12ull, row_sp->GetOffset());
+ EXPECT_TRUE(row_sp->GetCFAValue().GetRegisterNumber() == k_rsp);
+ EXPECT_EQ(152, row_sp->GetCFAValue().GetOffset());
+
+ // After the nop, we should still refer to the same row.
+ row_sp = unwind_plan.GetRowForFunctionOffset(13);
+ EXPECT_EQ(12ull, row_sp->GetOffset());
+
+ // Check that the second stack pointer update is reflected in the
+ // unwind plan.
+ row_sp = unwind_plan.GetRowForFunctionOffset(20);
+ EXPECT_EQ(20ull, row_sp->GetOffset());
+ EXPECT_TRUE(row_sp->GetCFAValue().GetRegisterNumber() == k_rsp);
+ EXPECT_EQ(16, row_sp->GetCFAValue().GetOffset());
+}
+
TEST_F(Testx86AssemblyInspectionEngine, TestSimplex86_64Augmented) {
UnwindPlan::Row::RegisterLocation regloc;
UnwindPlan::RowSP row_sp;
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