Add support for arm64 compact unwind tables, used on darwin arm64
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
diff --git a/lldb/source/Symbol/CompactUnwindInfo.cpp b/lldb/source/Symbol/CompactUnwindInfo.cpp
index 564f038..5f23f84 100644
--- a/lldb/source/Symbol/CompactUnwindInfo.cpp
+++ b/lldb/source/Symbol/CompactUnwindInfo.cpp
@@ -101,6 +101,27 @@
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 @@
{
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 @@
}
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;
+}
+