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Add support for arm64 compact unwind tables, used on darwin arm64

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systems (ios, tvos, watchos).  It's a simple format to use now that
I have i386/x86_64 supported already.

The unwind instructions are only valid at call sites -- that is,
when lldb is unwinding a frame in the middle of the stack.  It
cannot be used for the currently executing frame; it has no information
about prologues/epilogues/etc.

<rdar://problem/12062336> 

llvm-svn: 270658
This commit is contained in:
Jason Molenda 2016-05-25 04:20:28 +00:00
parent e66f45c6eb
commit b667c20222
3 changed files with 340 additions and 0 deletions
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3
lldb/include/lldb/Symbol/CompactUnwindInfo.h
View File

@ -133,6 +133,9 @@ private:
bool
CreateUnwindPlan_i386 (Target &target, FunctionInfo &function_info, UnwindPlan &unwind_plan, Address pc_or_function_start);
bool
CreateUnwindPlan_arm64 (Target &target, FunctionInfo &function_info, UnwindPlan &unwind_plan, Address pc_or_function_start);
ObjectFile &m_objfile;
lldb::SectionSP m_section_sp;
lldb::DataBufferSP m_section_contents_if_encrypted; // if the binary is encrypted, read the sect contents

188
lldb/source/Symbol/CompactUnwindInfo.cpp
View File

@ -101,6 +101,27 @@ namespace lldb_private {
UNWIND_X86_64_REG_R15 = 5,
UNWIND_X86_64_REG_RBP = 6,
};
FLAGS_ANONYMOUS_ENUM()
{
UNWIND_ARM64_MODE_MASK = 0x0F000000,
UNWIND_ARM64_MODE_FRAMELESS = 0x02000000,
UNWIND_ARM64_MODE_DWARF = 0x03000000,
UNWIND_ARM64_MODE_FRAME = 0x04000000,
UNWIND_ARM64_FRAME_X19_X20_PAIR = 0x00000001,
UNWIND_ARM64_FRAME_X21_X22_PAIR = 0x00000002,
UNWIND_ARM64_FRAME_X23_X24_PAIR = 0x00000004,
UNWIND_ARM64_FRAME_X25_X26_PAIR = 0x00000008,
UNWIND_ARM64_FRAME_X27_X28_PAIR = 0x00000010,
UNWIND_ARM64_FRAME_D8_D9_PAIR = 0x00000100,
UNWIND_ARM64_FRAME_D10_D11_PAIR = 0x00000200,
UNWIND_ARM64_FRAME_D12_D13_PAIR = 0x00000400,
UNWIND_ARM64_FRAME_D14_D15_PAIR = 0x00000800,
UNWIND_ARM64_FRAMELESS_STACK_SIZE_MASK = 0x00FFF000,
UNWIND_ARM64_DWARF_SECTION_OFFSET = 0x00FFFFFF,
};
}
@ -195,6 +216,10 @@ CompactUnwindInfo::GetUnwindPlan (Target &target, Address addr, UnwindPlan& unwi
{
return CreateUnwindPlan_x86_64 (target, function_info, unwind_plan, addr);
}
if (arch.GetTriple().getArch() == llvm::Triple::aarch64)
{
return CreateUnwindPlan_arm64 (target, function_info, unwind_plan, addr);
}
if (arch.GetTriple().getArch() == llvm::Triple::x86)
{
return CreateUnwindPlan_i386 (target, function_info, unwind_plan, addr);
@ -1229,3 +1254,166 @@ CompactUnwindInfo::CreateUnwindPlan_i386 (Target &target, FunctionInfo &function
}
return false;
}
// DWARF register numbers from "DWARF for the ARM 64-bit Architecture (AArch64)" doc by ARM
enum arm64_eh_regnum {
x19 = 19,
x20 = 20,
x21 = 21,
x22 = 22,
x23 = 23,
x24 = 24,
x25 = 25,
x26 = 26,
x27 = 27,
x28 = 28,
fp = 29,
ra = 30,
sp = 31,
pc = 32,
// Compact unwind encodes d8-d15 but we don't have eh_frame / dwarf reg #'s for the 64-bit
// fp regs. Normally in DWARF it's context sensitive - so it knows it is fetching a
// 32- or 64-bit quantity from reg v8 to indicate s0 or d0 - but the unwinder is operating
// at a lower level and we'd try to fetch 128 bits if we were told that v8 were stored on
// the stack...
v8 = 72,
v9 = 73,
v10 = 74,
v11 = 75,
v12 = 76,
v13 = 77,
v14 = 78,
v15 = 79,
};
bool
CompactUnwindInfo::CreateUnwindPlan_arm64 (Target &target, FunctionInfo &function_info, UnwindPlan &unwind_plan, Address pc_or_function_start)
{
unwind_plan.SetSourceName ("compact unwind info");
unwind_plan.SetSourcedFromCompiler (eLazyBoolYes);
unwind_plan.SetUnwindPlanValidAtAllInstructions (eLazyBoolNo);
unwind_plan.SetRegisterKind (eRegisterKindEHFrame);
unwind_plan.SetLSDAAddress (function_info.lsda_address);
unwind_plan.SetPersonalityFunctionPtr (function_info.personality_ptr_address);
UnwindPlan::RowSP row (new UnwindPlan::Row);
const int wordsize = 8;
int mode = function_info.encoding & UNWIND_ARM64_MODE_MASK;
if (mode == UNWIND_ARM64_MODE_DWARF)
return false;
if (mode == UNWIND_ARM64_MODE_FRAMELESS)
{
row->SetOffset (0);
uint32_t stack_size = (EXTRACT_BITS (function_info.encoding, UNWIND_ARM64_FRAMELESS_STACK_SIZE_MASK)) * 16;
// Our previous Call Frame Address is the stack pointer plus the stack size
row->GetCFAValue().SetIsRegisterPlusOffset (arm64_eh_regnum::sp, stack_size);
// Our previous PC is in the LR
row->SetRegisterLocationToRegister(arm64_eh_regnum::pc, arm64_eh_regnum::ra, true);
unwind_plan.AppendRow (row);
return true;
}
// Should not be possible
if (mode != UNWIND_ARM64_MODE_FRAME)
return false;
// mode == UNWIND_ARM64_MODE_FRAME
row->GetCFAValue().SetIsRegisterPlusOffset (arm64_eh_regnum::fp , 2 * wordsize);
row->SetOffset (0);
row->SetRegisterLocationToAtCFAPlusOffset (arm64_eh_regnum::fp, wordsize * -2, true);
row->SetRegisterLocationToAtCFAPlusOffset (arm64_eh_regnum::pc, wordsize * -1, true);
row->SetRegisterLocationToIsCFAPlusOffset (arm64_eh_regnum::sp, 0, true);
int reg_pairs_saved_count = 1;
uint32_t saved_register_bits = function_info.encoding & 0xfff;
if (saved_register_bits & UNWIND_ARM64_FRAME_X19_X20_PAIR)
{
int cfa_offset = reg_pairs_saved_count * -2 * wordsize;
cfa_offset -= wordsize;
row->SetRegisterLocationToAtCFAPlusOffset (arm64_eh_regnum::x19, cfa_offset, true);
cfa_offset -= wordsize;
row->SetRegisterLocationToAtCFAPlusOffset (arm64_eh_regnum::x20, cfa_offset, true);
reg_pairs_saved_count++;
}
if (saved_register_bits & UNWIND_ARM64_FRAME_X21_X22_PAIR)
{
int cfa_offset = reg_pairs_saved_count * -2 * wordsize;
cfa_offset -= wordsize;
row->SetRegisterLocationToAtCFAPlusOffset (arm64_eh_regnum::x21, cfa_offset, true);
cfa_offset -= wordsize;
row->SetRegisterLocationToAtCFAPlusOffset (arm64_eh_regnum::x22, cfa_offset, true);
reg_pairs_saved_count++;
}
if (saved_register_bits & UNWIND_ARM64_FRAME_X23_X24_PAIR)
{
int cfa_offset = reg_pairs_saved_count * -2 * wordsize;
cfa_offset -= wordsize;
row->SetRegisterLocationToAtCFAPlusOffset (arm64_eh_regnum::x23, cfa_offset, true);
cfa_offset -= wordsize;
row->SetRegisterLocationToAtCFAPlusOffset (arm64_eh_regnum::x24, cfa_offset, true);
reg_pairs_saved_count++;
}
if (saved_register_bits & UNWIND_ARM64_FRAME_X25_X26_PAIR)
{
int cfa_offset = reg_pairs_saved_count * -2 * wordsize;
cfa_offset -= wordsize;
row->SetRegisterLocationToAtCFAPlusOffset (arm64_eh_regnum::x25, cfa_offset, true);
cfa_offset -= wordsize;
row->SetRegisterLocationToAtCFAPlusOffset (arm64_eh_regnum::x26, cfa_offset, true);
reg_pairs_saved_count++;
}
if (saved_register_bits & UNWIND_ARM64_FRAME_X27_X28_PAIR)
{
int cfa_offset = reg_pairs_saved_count * -2 * wordsize;
cfa_offset -= wordsize;
row->SetRegisterLocationToAtCFAPlusOffset (arm64_eh_regnum::x27, cfa_offset, true);
cfa_offset -= wordsize;
row->SetRegisterLocationToAtCFAPlusOffset (arm64_eh_regnum::x28, cfa_offset, true);
reg_pairs_saved_count++;
}
// If we use the v8-v15 regnums here, the unwinder will try to grab 128 bits off the stack;
// not sure if we have a good way to represent the 64-bitness of these saves.
if (saved_register_bits & UNWIND_ARM64_FRAME_D8_D9_PAIR)
{
reg_pairs_saved_count++;
}
if (saved_register_bits & UNWIND_ARM64_FRAME_D10_D11_PAIR)
{
reg_pairs_saved_count++;
}
if (saved_register_bits & UNWIND_ARM64_FRAME_D12_D13_PAIR)
{
reg_pairs_saved_count++;
}
if (saved_register_bits & UNWIND_ARM64_FRAME_D14_D15_PAIR)
{
reg_pairs_saved_count++;
}
unwind_plan.AppendRow (row);
return true;
}

149
lldb/tools/compact-unwind/compact-unwind-dumper.c
View File

@ -14,6 +14,28 @@
#include <stdio.h>
#include <mach-o/nlist.h>
enum {
UNWIND_ARM64_MODE_MASK = 0x0F000000,
UNWIND_ARM64_MODE_FRAMELESS = 0x02000000,
UNWIND_ARM64_MODE_DWARF = 0x03000000,
UNWIND_ARM64_MODE_FRAME = 0x04000000,
UNWIND_ARM64_FRAME_X19_X20_PAIR = 0x00000001,
UNWIND_ARM64_FRAME_X21_X22_PAIR = 0x00000002,
UNWIND_ARM64_FRAME_X23_X24_PAIR = 0x00000004,
UNWIND_ARM64_FRAME_X25_X26_PAIR = 0x00000008,
UNWIND_ARM64_FRAME_X27_X28_PAIR = 0x00000010,
UNWIND_ARM64_FRAME_D8_D9_PAIR = 0x00000100,
UNWIND_ARM64_FRAME_D10_D11_PAIR = 0x00000200,
UNWIND_ARM64_FRAME_D12_D13_PAIR = 0x00000400,
UNWIND_ARM64_FRAME_D14_D15_PAIR = 0x00000800,
UNWIND_ARM64_FRAMELESS_STACK_SIZE_MASK = 0x00FFF000,
UNWIND_ARM64_DWARF_SECTION_OFFSET = 0x00FFFFFF,
};
#define EXTRACT_BITS(value, mask) \
( (value >> __builtin_ctz(mask)) & (((1 << __builtin_popcount(mask)))-1) )
@ -901,6 +923,129 @@ print_encoding_i386 (struct baton baton, uint8_t *function_start, uint32_t encod
}
}
void
print_encoding_arm64 (struct baton baton, uint8_t *function_start, uint32_t encoding)
{
const int wordsize = 8;
int mode = encoding & UNWIND_ARM64_MODE_MASK;
switch (mode)
{
case UNWIND_ARM64_MODE_FRAME:
{
printf ("frame func: CFA is fp+%d ", 16);
printf (" pc=[CFA-8] fp=[CFA-16]");
int reg_pairs_saved_count = 1;
uint32_t saved_register_bits = encoding & 0xfff;
if (saved_register_bits & UNWIND_ARM64_FRAME_X19_X20_PAIR)
{
int cfa_offset = reg_pairs_saved_count * -2 * wordsize;
cfa_offset -= wordsize;
printf (" x19=[CFA%d]", cfa_offset);
cfa_offset -= wordsize;
printf (" x20=[CFA%d]", cfa_offset);
reg_pairs_saved_count++;
}
if (saved_register_bits & UNWIND_ARM64_FRAME_X21_X22_PAIR)
{
int cfa_offset = reg_pairs_saved_count * -2 * wordsize;
cfa_offset -= wordsize;
printf (" x21=[CFA%d]", cfa_offset);
cfa_offset -= wordsize;
printf (" x22=[CFA%d]", cfa_offset);
reg_pairs_saved_count++;
}
if (saved_register_bits & UNWIND_ARM64_FRAME_X23_X24_PAIR)
{
int cfa_offset = reg_pairs_saved_count * -2 * wordsize;
cfa_offset -= wordsize;
printf (" x23=[CFA%d]", cfa_offset);
cfa_offset -= wordsize;
printf (" x24=[CFA%d]", cfa_offset);
reg_pairs_saved_count++;
}
if (saved_register_bits & UNWIND_ARM64_FRAME_X25_X26_PAIR)
{
int cfa_offset = reg_pairs_saved_count * -2 * wordsize;
cfa_offset -= wordsize;
printf (" x25=[CFA%d]", cfa_offset);
cfa_offset -= wordsize;
printf (" x26=[CFA%d]", cfa_offset);
reg_pairs_saved_count++;
}
if (saved_register_bits & UNWIND_ARM64_FRAME_X27_X28_PAIR)
{
int cfa_offset = reg_pairs_saved_count * -2 * wordsize;
cfa_offset -= wordsize;
printf (" x27=[CFA%d]", cfa_offset);
cfa_offset -= wordsize;
printf (" x28=[CFA%d]", cfa_offset);
reg_pairs_saved_count++;
}
if (saved_register_bits & UNWIND_ARM64_FRAME_D8_D9_PAIR)
{
int cfa_offset = reg_pairs_saved_count * -2 * wordsize;
cfa_offset -= wordsize;
printf (" d8=[CFA%d]", cfa_offset);
cfa_offset -= wordsize;
printf (" d9=[CFA%d]", cfa_offset);
reg_pairs_saved_count++;
}
if (saved_register_bits & UNWIND_ARM64_FRAME_D10_D11_PAIR)
{
int cfa_offset = reg_pairs_saved_count * -2 * wordsize;
cfa_offset -= wordsize;
printf (" d10=[CFA%d]", cfa_offset);
cfa_offset -= wordsize;
printf (" d11=[CFA%d]", cfa_offset);
reg_pairs_saved_count++;
}
if (saved_register_bits & UNWIND_ARM64_FRAME_D12_D13_PAIR)
{
int cfa_offset = reg_pairs_saved_count * -2 * wordsize;
cfa_offset -= wordsize;
printf (" d12=[CFA%d]", cfa_offset);
cfa_offset -= wordsize;
printf (" d13=[CFA%d]", cfa_offset);
reg_pairs_saved_count++;
}
if (saved_register_bits & UNWIND_ARM64_FRAME_D14_D15_PAIR)
{
int cfa_offset = reg_pairs_saved_count * -2 * wordsize;
cfa_offset -= wordsize;
printf (" d14=[CFA%d]", cfa_offset);
cfa_offset -= wordsize;
printf (" d15=[CFA%d]", cfa_offset);
reg_pairs_saved_count++;
}
}
break;
case UNWIND_ARM64_MODE_FRAMELESS:
{
uint32_t stack_size = encoding & UNWIND_ARM64_FRAMELESS_STACK_SIZE_MASK;
printf ("frameless function: stack size %d ", stack_size * 16);
}
break;
case UNWIND_ARM64_MODE_DWARF:
{
uint32_t dwarf_offset = encoding & UNWIND_ARM64_DWARF_SECTION_OFFSET;
printf ("DWARF unwind instructions: FDE at offset %d (file address 0x%" PRIx64 ")",
dwarf_offset, dwarf_offset + baton.eh_section_file_address);
}
break;
case 0:
{
printf (" no unwind information");
}
break;
}
}
void print_encoding (struct baton baton, uint8_t *function_start, uint32_t encoding)
{
@ -913,6 +1058,10 @@ void print_encoding (struct baton baton, uint8_t *function_start, uint32_t encod
{
print_encoding_i386 (baton, function_start, encoding);
}
else if (baton.cputype == CPU_TYPE_ARM64)
{
print_encoding_arm64 (baton, function_start, encoding);
}
else
{
printf (" -- unsupported encoding arch -- ");