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Fix x86 return pattern detection
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Summary: Replace 0xc9 (LEAVE) with 0xcb (RETF) in ret_pattern_p(). Also put 0xc3 first, since it is the most common form and will match first.

Reviewers: jasonmolenda

Reviewed By: jasonmolenda

Subscribers: labath, lldb-commits

Tags: #lldb

Differential Revision: https://reviews.llvm.org/D57928

llvm-svn: 353643
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Teemperor committed Feb 10, 2019
1 parent ada705a commit d1307ec
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Showing 2 changed files with 172 additions and 2 deletions.
Original file line number Diff line number Diff line change
Expand Up @@ -665,10 +665,10 @@ bool x86AssemblyInspectionEngine::mov_reg_to_local_stack_frame_p(
return false;
}

// ret [0xc9] or [0xc2 imm8] or [0xca imm8]
// ret [0xc3] or [0xcb] or [0xc2 imm16] or [0xca imm16]
bool x86AssemblyInspectionEngine::ret_pattern_p() {
uint8_t *p = m_cur_insn;
return *p == 0xc9 || *p == 0xc2 || *p == 0xca || *p == 0xc3;
return *p == 0xc3 || *p == 0xc2 || *p == 0xca || *p == 0xcb;
}

uint32_t x86AssemblyInspectionEngine::extract_4(uint8_t *b) {
Expand Down
170 changes: 170 additions & 0 deletions lldb/unittests/UnwindAssembly/x86/Testx86AssemblyInspectionEngine.cpp
Original file line number Diff line number Diff line change
Expand Up @@ -2552,3 +2552,173 @@ TEST_F(Testx86AssemblyInspectionEngine, TestDisassemblyJunkBytes) {

}

TEST_F(Testx86AssemblyInspectionEngine, TestReturnDetect) {
std::unique_ptr<x86AssemblyInspectionEngine> engine = Getx86_64Inspector();

// Single fragment with all four return forms.
// We want to verify that the unwind state is reset after each ret.
uint8_t data[] = {
0x55, // offset 0 -- pushq %rbp
0x48, 0x89, 0xe5, // offset 1 -- movq %rsp, %rbp
0x31, 0xc0, // offset 4 -- xorl %eax, %eax
0x5d, // offset 6 -- popq %rbp
0xc3, // offset 7 -- retq
0x31, 0xc0, // offset 8 -- xorl %eax, %eax
0x5d, // offset 10 -- popq %rbp
0xcb, // offset 11 -- retf
0x31, 0xc0, // offset 12 -- xorl %eax, %eax
0x5d, // offset 14 -- popq %rbp
0xc2, 0x22, 0x11, // offset 15 -- retq 0x1122
0x31, 0xc0, // offset 18 -- xorl %eax, %eax
0x5d, // offset 20 -- popq %rbp
0xca, 0x44, 0x33, // offset 21 -- retf 0x3344
0x31, 0xc0, // offset 24 -- xorl %eax, %eax
};

AddressRange sample_range(0x1000, sizeof(data));

UnwindPlan unwind_plan(eRegisterKindLLDB);
EXPECT_TRUE(engine->GetNonCallSiteUnwindPlanFromAssembly(
data, sizeof(data), sample_range, unwind_plan));

// Expect following unwind rows:
// 0: CFA=rsp +8 => rsp=CFA+0 rip=[CFA-8]
// 1: CFA=rsp+16 => rbp=[CFA-16] rsp=CFA+0 rip=[CFA-8]
// 4: CFA=rbp+16 => rbp=[CFA-16] rsp=CFA+0 rip=[CFA-8]
// 7: CFA=rsp +8 => rsp=CFA+0 rip=[CFA-8]
// 8: CFA=rbp+16 => rbp=[CFA-16] rsp=CFA+0 rip=[CFA-8]
// 11: CFA=rsp +8 => rsp=CFA+0 rip=[CFA-8]
// 12: CFA=rbp+16 => rbp=[CFA-16] rsp=CFA+0 rip=[CFA-8]
// 15: CFA=rsp +8 => rsp=CFA+0 rip=[CFA-8]
// 18: CFA=rbp+16 => rbp=[CFA-16] rsp=CFA+0 rip=[CFA-8]
// 21: CFA=rsp +8 => rsp=CFA+0 rip=[CFA-8]
// 24: CFA=rbp+16 => rbp=[CFA-16] rsp=CFA+0 rip=[CFA-8]

EXPECT_TRUE(unwind_plan.GetInitialCFARegister() == k_rsp);
EXPECT_TRUE(unwind_plan.GetUnwindPlanValidAtAllInstructions() ==
eLazyBoolYes);
EXPECT_TRUE(unwind_plan.GetSourcedFromCompiler() == eLazyBoolNo);

UnwindPlan::Row::RegisterLocation regloc;

// 0: CFA=rsp +8 => rsp=CFA+0 rip=[CFA-8]
UnwindPlan::RowSP row_sp = unwind_plan.GetRowForFunctionOffset(0);
EXPECT_EQ(0ull, row_sp->GetOffset());
EXPECT_TRUE(row_sp->GetCFAValue().GetRegisterNumber() == k_rsp);
EXPECT_TRUE(row_sp->GetCFAValue().IsRegisterPlusOffset() == true);
EXPECT_EQ(8, row_sp->GetCFAValue().GetOffset());

EXPECT_TRUE(row_sp->GetRegisterInfo(k_rip, regloc));
EXPECT_TRUE(regloc.IsAtCFAPlusOffset());
EXPECT_EQ(-8, regloc.GetOffset());

// 1: CFA=rsp+16 => rbp=[CFA-16] rsp=CFA+0 rip=[CFA-8]
row_sp = unwind_plan.GetRowForFunctionOffset(1);
EXPECT_EQ(1ull, row_sp->GetOffset());
EXPECT_TRUE(row_sp->GetCFAValue().GetRegisterNumber() == k_rsp);
EXPECT_TRUE(row_sp->GetCFAValue().IsRegisterPlusOffset() == true);
EXPECT_EQ(16, row_sp->GetCFAValue().GetOffset());

EXPECT_TRUE(row_sp->GetRegisterInfo(k_rip, regloc));
EXPECT_TRUE(regloc.IsAtCFAPlusOffset());
EXPECT_EQ(-8, regloc.GetOffset());

// 4: CFA=rbp+16 => rbp=[CFA-16] rsp=CFA+0 rip=[CFA-8]
row_sp = unwind_plan.GetRowForFunctionOffset(4);
EXPECT_EQ(4ull, row_sp->GetOffset());
EXPECT_TRUE(row_sp->GetCFAValue().GetRegisterNumber() == k_rbp);
EXPECT_TRUE(row_sp->GetCFAValue().IsRegisterPlusOffset() == true);
EXPECT_EQ(16, row_sp->GetCFAValue().GetOffset());

EXPECT_TRUE(row_sp->GetRegisterInfo(k_rip, regloc));
EXPECT_TRUE(regloc.IsAtCFAPlusOffset());
EXPECT_EQ(-8, regloc.GetOffset());

// 7: CFA=rsp +8 => rsp=CFA+0 rip=[CFA-8]
row_sp = unwind_plan.GetRowForFunctionOffset(7);
EXPECT_EQ(7ull, row_sp->GetOffset());
EXPECT_TRUE(row_sp->GetCFAValue().GetRegisterNumber() == k_rsp);
EXPECT_TRUE(row_sp->GetCFAValue().IsRegisterPlusOffset() == true);
EXPECT_EQ(8, row_sp->GetCFAValue().GetOffset());

EXPECT_TRUE(row_sp->GetRegisterInfo(k_rip, regloc));
EXPECT_TRUE(regloc.IsAtCFAPlusOffset());
EXPECT_EQ(-8, regloc.GetOffset());

// 8: CFA=rbp+16 => rbp=[CFA-16] rsp=CFA+0 rip=[CFA-8]
row_sp = unwind_plan.GetRowForFunctionOffset(8);
EXPECT_EQ(8ull, row_sp->GetOffset());
EXPECT_TRUE(row_sp->GetCFAValue().GetRegisterNumber() == k_rbp);
EXPECT_TRUE(row_sp->GetCFAValue().IsRegisterPlusOffset() == true);
EXPECT_EQ(16, row_sp->GetCFAValue().GetOffset());

EXPECT_TRUE(row_sp->GetRegisterInfo(k_rip, regloc));
EXPECT_TRUE(regloc.IsAtCFAPlusOffset());
EXPECT_EQ(-8, regloc.GetOffset());

// 11: CFA=rsp +8 => rsp=CFA+0 rip=[CFA-8]
row_sp = unwind_plan.GetRowForFunctionOffset(11);
EXPECT_EQ(11ull, row_sp->GetOffset());
EXPECT_TRUE(row_sp->GetCFAValue().GetRegisterNumber() == k_rsp);
EXPECT_TRUE(row_sp->GetCFAValue().IsRegisterPlusOffset() == true);
EXPECT_EQ(8, row_sp->GetCFAValue().GetOffset());

EXPECT_TRUE(row_sp->GetRegisterInfo(k_rip, regloc));
EXPECT_TRUE(regloc.IsAtCFAPlusOffset());
EXPECT_EQ(-8, regloc.GetOffset());

// 12: CFA=rbp+16 => rbp=[CFA-16] rsp=CFA+0 rip=[CFA-8]
row_sp = unwind_plan.GetRowForFunctionOffset(12);
EXPECT_EQ(12ull, row_sp->GetOffset());
EXPECT_TRUE(row_sp->GetCFAValue().GetRegisterNumber() == k_rbp);
EXPECT_TRUE(row_sp->GetCFAValue().IsRegisterPlusOffset() == true);
EXPECT_EQ(16, row_sp->GetCFAValue().GetOffset());

EXPECT_TRUE(row_sp->GetRegisterInfo(k_rip, regloc));
EXPECT_TRUE(regloc.IsAtCFAPlusOffset());
EXPECT_EQ(-8, regloc.GetOffset());

// 15: CFA=rsp +8 => rsp=CFA+0 rip=[CFA-8]
row_sp = unwind_plan.GetRowForFunctionOffset(15);
EXPECT_EQ(15ull, row_sp->GetOffset());
EXPECT_TRUE(row_sp->GetCFAValue().GetRegisterNumber() == k_rsp);
EXPECT_TRUE(row_sp->GetCFAValue().IsRegisterPlusOffset() == true);
EXPECT_EQ(8, row_sp->GetCFAValue().GetOffset());

EXPECT_TRUE(row_sp->GetRegisterInfo(k_rip, regloc));
EXPECT_TRUE(regloc.IsAtCFAPlusOffset());
EXPECT_EQ(-8, regloc.GetOffset());

// 18: CFA=rbp+16 => rbp=[CFA-16] rsp=CFA+0 rip=[CFA-8]
row_sp = unwind_plan.GetRowForFunctionOffset(18);
EXPECT_EQ(18ull, row_sp->GetOffset());
EXPECT_TRUE(row_sp->GetCFAValue().GetRegisterNumber() == k_rbp);
EXPECT_TRUE(row_sp->GetCFAValue().IsRegisterPlusOffset() == true);
EXPECT_EQ(16, row_sp->GetCFAValue().GetOffset());

EXPECT_TRUE(row_sp->GetRegisterInfo(k_rip, regloc));
EXPECT_TRUE(regloc.IsAtCFAPlusOffset());
EXPECT_EQ(-8, regloc.GetOffset());

// 21: CFA=rsp +8 => rsp=CFA+0 rip=[CFA-8]
row_sp = unwind_plan.GetRowForFunctionOffset(21);
EXPECT_EQ(21ull, row_sp->GetOffset());
EXPECT_TRUE(row_sp->GetCFAValue().GetRegisterNumber() == k_rsp);
EXPECT_TRUE(row_sp->GetCFAValue().IsRegisterPlusOffset() == true);
EXPECT_EQ(8, row_sp->GetCFAValue().GetOffset());

EXPECT_TRUE(row_sp->GetRegisterInfo(k_rip, regloc));
EXPECT_TRUE(regloc.IsAtCFAPlusOffset());
EXPECT_EQ(-8, regloc.GetOffset());

// 24: CFA=rbp+16 => rbp=[CFA-16] rsp=CFA+0 rip=[CFA-8]
row_sp = unwind_plan.GetRowForFunctionOffset(24);
EXPECT_EQ(24ull, row_sp->GetOffset());
EXPECT_TRUE(row_sp->GetCFAValue().GetRegisterNumber() == k_rbp);
EXPECT_TRUE(row_sp->GetCFAValue().IsRegisterPlusOffset() == true);
EXPECT_EQ(16, row_sp->GetCFAValue().GetOffset());

EXPECT_TRUE(row_sp->GetRegisterInfo(k_rip, regloc));
EXPECT_TRUE(regloc.IsAtCFAPlusOffset());
EXPECT_EQ(-8, regloc.GetOffset());
}

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