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[lldb] [ABI/X86] Support combining xmm* and ymm*h regs into ymm*
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gdbserver does not expose combined ymm* registers but rather XSAVE-style
split xmm* and ymm*h portions.  Extend value_regs to support combining
multiple registers and use it to create user-friendly ymm* registers
that are combined from split xmm* and ymm*h portions.

Differential Revision: https://reviews.llvm.org/D108937
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@mgorny
mgorny committed Oct 20, 2021
1 parent 99277a8 commit f290efc
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Showing 6 changed files with 186 additions and 31 deletions.
6 changes: 4 additions & 2 deletions lldb/include/lldb/lldb-private-types.h
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Original file line number Diff line number Diff line change
Expand Up @@ -51,8 +51,10 @@ struct RegisterInfo {
/// List of registers (terminated with LLDB_INVALID_REGNUM). If this value is
/// not null, all registers in this list will be read first, at which point
/// the value for this register will be valid. For example, the value list
/// for ah would be eax (x86) or rax (x64).
uint32_t *value_regs; //
/// for ah would be eax (x86) or rax (x64). Register numbers are
/// of eRegisterKindLLDB. If multiple registers are listed, the final
/// value will be the concatenation of them.
uint32_t *value_regs;
/// List of registers (terminated with LLDB_INVALID_REGNUM). If this value is
/// not null, all registers in this list will be invalidated when the value of
/// this register changes. For example, the invalidate list for eax would be
Expand Down
71 changes: 64 additions & 7 deletions lldb/source/Plugins/ABI/X86/ABIX86.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -85,6 +85,46 @@ addPartialRegisters(std::vector<DynamicRegisterInfo::Register> &regs,
}
}

static void
addCombinedRegisters(std::vector<DynamicRegisterInfo::Register> &regs,
llvm::ArrayRef<RegData *> subregs1,
llvm::ArrayRef<RegData *> subregs2, uint32_t base_size,
lldb::Encoding encoding, lldb::Format format) {
for (auto it : llvm::zip(subregs1, subregs2)) {
RegData *regdata1, *regdata2;
std::tie(regdata1, regdata2) = it;
assert(regdata1);
assert(regdata2);

// verify that we've got matching target registers
if (regdata1->subreg_name != regdata2->subreg_name)
continue;

uint32_t base_index1 = regdata1->base_index.getValue();
uint32_t base_index2 = regdata2->base_index.getValue();
if (regs[base_index1].byte_size != base_size ||
regs[base_index2].byte_size != base_size)
continue;

lldb_private::DynamicRegisterInfo::Register new_reg{
lldb_private::ConstString(regdata1->subreg_name),
lldb_private::ConstString(),
lldb_private::ConstString("supplementary registers"),
base_size * 2,
LLDB_INVALID_INDEX32,
encoding,
format,
LLDB_INVALID_REGNUM,
LLDB_INVALID_REGNUM,
LLDB_INVALID_REGNUM,
LLDB_INVALID_REGNUM,
{base_index1, base_index2},
{}};

addSupplementaryRegister(regs, new_reg);
}
}

typedef llvm::SmallDenseMap<llvm::StringRef, llvm::SmallVector<RegData, 4>, 64>
BaseRegToRegsMap;

Expand Down Expand Up @@ -121,19 +161,33 @@ typedef llvm::SmallDenseMap<llvm::StringRef, llvm::SmallVector<RegData, 4>, 64>
#define STMM(n) \
{ BaseRegToRegsMap::value_type("st" #n, {{MM, "mm" #n, llvm::None}}) }

#define YMM(n) \
{BaseRegToRegsMap::value_type("ymm" #n "h", \
{{YMM_YMMh, "ymm" #n, llvm::None}})}, \
{ \
BaseRegToRegsMap::value_type("xmm" #n, {{YMM_XMM, "ymm" #n, llvm::None}}) \
}

BaseRegToRegsMap makeBaseRegMap(bool is64bit) {
BaseRegToRegsMap out{{// GPRs common to amd64 & i386
GPRh("a"), GPRh("b"), GPRh("c"), GPRh("d"), GPR("si"),
GPR("di"), GPR("bp"), GPR("sp"),
BaseRegToRegsMap out{
{// GPRs common to amd64 & i386
GPRh("a"), GPRh("b"), GPRh("c"), GPRh("d"), GPR("si"), GPR("di"),
GPR("bp"), GPR("sp"),

// ST/MM registers
STMM(0), STMM(1), STMM(2), STMM(3), STMM(4), STMM(5),
STMM(6), STMM(7)}};
// ST/MM registers
STMM(0), STMM(1), STMM(2), STMM(3), STMM(4), STMM(5), STMM(6), STMM(7),

// lower YMM registers (common to amd64 & i386)
YMM(0), YMM(1), YMM(2), YMM(3), YMM(4), YMM(5), YMM(6), YMM(7)}};

if (is64bit) {
BaseRegToRegsMap amd64_regs{{// GPRs specific to amd64
GPR64(8), GPR64(9), GPR64(10), GPR64(11),
GPR64(12), GPR64(13), GPR64(14), GPR64(15)}};
GPR64(12), GPR64(13), GPR64(14), GPR64(15),

// higher YMM registers (specific to amd64)
YMM(8), YMM(9), YMM(10), YMM(11), YMM(12),
YMM(13), YMM(14), YMM(15)}};
out.insert(amd64_regs.begin(), amd64_regs.end());
}

Expand Down Expand Up @@ -197,4 +251,7 @@ void ABIX86::AugmentRegisterInfo(

addPartialRegisters(regs, subreg_by_kind[MM], 10, eEncodingUint, eFormatHex,
8);

addCombinedRegisters(regs, subreg_by_kind[YMM_XMM], subreg_by_kind[YMM_YMMh],
16, eEncodingVector, eFormatVectorOfUInt8);
}
66 changes: 60 additions & 6 deletions lldb/source/Plugins/Process/gdb-remote/GDBRemoteRegisterContext.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -87,10 +87,34 @@ bool GDBRemoteRegisterContext::ReadRegister(const RegisterInfo *reg_info,
const uint32_t reg = reg_info->kinds[eRegisterKindLLDB];
if (m_reg_valid[reg] == false)
return false;
const bool partial_data_ok = false;
Status error(value.SetValueFromData(
reg_info, m_reg_data, reg_info->byte_offset, partial_data_ok));
return error.Success();
if (reg_info->value_regs &&
reg_info->value_regs[0] != LLDB_INVALID_REGNUM &&
reg_info->value_regs[1] != LLDB_INVALID_REGNUM) {
std::vector<char> combined_data;
uint32_t offset = 0;
for (int i = 0; reg_info->value_regs[i] != LLDB_INVALID_REGNUM; i++) {
const RegisterInfo *parent_reg = GetRegisterInfo(
eRegisterKindLLDB, reg_info->value_regs[i]);
if (!parent_reg)
return false;
combined_data.resize(offset + parent_reg->byte_size);
if (m_reg_data.CopyData(parent_reg->byte_offset, parent_reg->byte_size,
combined_data.data() + offset) !=
parent_reg->byte_size)
return false;
offset += parent_reg->byte_size;
}

Status error;
return value.SetFromMemoryData(
reg_info, combined_data.data(), combined_data.size(),
m_reg_data.GetByteOrder(), error) == combined_data.size();
} else {
const bool partial_data_ok = false;
Status error(value.SetValueFromData(
reg_info, m_reg_data, reg_info->byte_offset, partial_data_ok));
return error.Success();
}
}
return false;
}
Expand Down Expand Up @@ -272,8 +296,38 @@ bool GDBRemoteRegisterContext::ReadRegisterBytes(const RegisterInfo *reg_info) {
bool GDBRemoteRegisterContext::WriteRegister(const RegisterInfo *reg_info,
const RegisterValue &value) {
DataExtractor data;
if (value.GetData(data))
return WriteRegisterBytes(reg_info, data, 0);
if (value.GetData(data)) {
if (reg_info->value_regs &&
reg_info->value_regs[0] != LLDB_INVALID_REGNUM &&
reg_info->value_regs[1] != LLDB_INVALID_REGNUM) {
uint32_t combined_size = 0;
for (int i = 0; reg_info->value_regs[i] != LLDB_INVALID_REGNUM; i++) {
const RegisterInfo *parent_reg = GetRegisterInfo(
eRegisterKindLLDB, reg_info->value_regs[i]);
if (!parent_reg)
return false;
combined_size += parent_reg->byte_size;
}

if (data.GetByteSize() < combined_size)
return false;

uint32_t offset = 0;
for (int i = 0; reg_info->value_regs[i] != LLDB_INVALID_REGNUM; i++) {
const RegisterInfo *parent_reg = GetRegisterInfo(
eRegisterKindLLDB, reg_info->value_regs[i]);
assert(parent_reg);

DataExtractor parent_data{data, offset, parent_reg->byte_size};
if (!WriteRegisterBytes(parent_reg, parent_data, 0))
return false;
offset += parent_reg->byte_size;
}
assert(offset == combined_size);
return true;
} else
return WriteRegisterBytes(reg_info, data, 0);
}
return false;
}

Expand Down
4 changes: 3 additions & 1 deletion lldb/source/Plugins/Process/gdb-remote/ProcessGDBRemote.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -4311,7 +4311,9 @@ bool ParseRegisters(XMLNode feature_node, GdbServerTargetInfo &target_info,
reg_info.encoding = eEncodingIEEE754;
} else if (gdb_type == "aarch64v" ||
llvm::StringRef(gdb_type).startswith("vec") ||
gdb_type == "i387_ext") {
gdb_type == "i387_ext" || gdb_type == "uint128") {
// lldb doesn't handle 128-bit uints correctly (for ymm*h), so treat
// them as vector (similarly to xmm/ymm)
reg_info.format = eFormatVectorOfUInt8;
reg_info.encoding = eEncodingVector;
}
Expand Down
24 changes: 9 additions & 15 deletions lldb/source/Target/DynamicRegisterInfo.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -463,20 +463,11 @@ void DynamicRegisterInfo::Finalize(const ArchSpec &arch) {
m_sets[set].registers = m_set_reg_nums[set].data();
}

// sort and unique all value registers and make sure each is terminated with
// LLDB_INVALID_REGNUM
// make sure value_regs are terminated with LLDB_INVALID_REGNUM

for (reg_to_regs_map::iterator pos = m_value_regs_map.begin(),
end = m_value_regs_map.end();
pos != end; ++pos) {
if (pos->second.size() > 1) {
llvm::sort(pos->second.begin(), pos->second.end());
reg_num_collection::iterator unique_end =
std::unique(pos->second.begin(), pos->second.end());
if (unique_end != pos->second.end())
pos->second.erase(unique_end, pos->second.end());
}
assert(!pos->second.empty());
if (pos->second.back() != LLDB_INVALID_REGNUM)
pos->second.push_back(LLDB_INVALID_REGNUM);
}
Expand Down Expand Up @@ -678,13 +669,16 @@ void DynamicRegisterInfo::ConfigureOffsets() {
// Now update all value_regs with each register info as needed
for (auto &reg : m_regs) {
if (reg.value_regs != nullptr) {
// Assign a valid offset to all pseudo registers if not assigned by stub.
// Pseudo registers with value_regs list populated will share same offset
// as that of their corresponding primary register in value_regs list.
// Assign a valid offset to all pseudo registers that have only a single
// parent register in value_regs list, if not assigned by stub. Pseudo
// registers with value_regs list populated will share same offset as
// that of their corresponding parent register.
if (reg.byte_offset == LLDB_INVALID_INDEX32) {
uint32_t value_regnum = reg.value_regs[0];
if (value_regnum != LLDB_INVALID_INDEX32) {
reg.byte_offset = GetRegisterInfoAtIndex(value_regnum)->byte_offset;
if (value_regnum != LLDB_INVALID_INDEX32 &&
reg.value_regs[1] == LLDB_INVALID_INDEX32) {
reg.byte_offset =
GetRegisterInfoAtIndex(value_regnum)->byte_offset;
auto it = m_value_reg_offset_map.find(reg.kinds[eRegisterKindLLDB]);
if (it != m_value_reg_offset_map.end())
reg.byte_offset += it->second;
Expand Down
46 changes: 46 additions & 0 deletions lldb/test/API/functionalities/gdb_remote_client/TestGDBServerTargetXML.py
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Original file line number Diff line number Diff line change
Expand Up @@ -199,6 +199,29 @@ def haltReason(self):
self.match("register read st0",
["st0 = {0xf8 0xf9 0xfa 0xfb 0xfc 0xfd 0xfe 0xff 0x09 0x0a}"])

self.runCmd("register write xmm0 \"{0xff 0xfe 0xfd 0xfc 0xfb 0xfa 0xf9 "
"0xf8 0xf7 0xf6 0xf5 0xf4 0xf3 0xf2 0xf1 0xf0}\"")
self.match("register read ymm0",
["ymm0 = {0xff 0xfe 0xfd 0xfc 0xfb 0xfa 0xf9 0xf8 0xf7 0xf6 "
"0xf5 0xf4 0xf3 0xf2 0xf1 0xf0 0xb1 0xb2 0xb3 0xb4 0xb5 "
"0xb6 0xb7 0xb8 0xb9 0xba 0xbb 0xbc 0xbd 0xbe 0xbf 0xc0}"])

self.runCmd("register write ymm0h \"{0xef 0xee 0xed 0xec 0xeb 0xea 0xe9 "
"0xe8 0xe7 0xe6 0xe5 0xe4 0xe3 0xe2 0xe1 0xe0}\"")
self.match("register read ymm0",
["ymm0 = {0xff 0xfe 0xfd 0xfc 0xfb 0xfa 0xf9 0xf8 0xf7 0xf6 "
"0xf5 0xf4 0xf3 0xf2 0xf1 0xf0 0xef 0xee 0xed 0xec 0xeb "
"0xea 0xe9 0xe8 0xe7 0xe6 0xe5 0xe4 0xe3 0xe2 0xe1 0xe0}"])

self.runCmd("register write ymm0 \"{0xd0 0xd1 0xd2 0xd3 0xd4 0xd5 0xd6 "
"0xd7 0xd8 0xd9 0xda 0xdb 0xdc 0xdd 0xde 0xdf 0xe0 0xe1 "
"0xe2 0xe3 0xe4 0xe5 0xe6 0xe7 0xe8 0xe9 0xea 0xeb 0xec "
"0xed 0xee 0xef}\"")
self.match("register read ymm0",
["ymm0 = {0xd0 0xd1 0xd2 0xd3 0xd4 0xd5 0xd6 0xd7 0xd8 0xd9 "
"0xda 0xdb 0xdc 0xdd 0xde 0xdf 0xe0 0xe1 0xe2 0xe3 0xe4 "
"0xe5 0xe6 0xe7 0xe8 0xe9 0xea 0xeb 0xec 0xed 0xee 0xef}"])

@skipIfXmlSupportMissing
@skipIfRemote
@skipIfLLVMTargetMissing("X86")
Expand Down Expand Up @@ -361,6 +384,29 @@ def haltReason(self):
self.match("register read st0",
["st0 = {0xf8 0xf9 0xfa 0xfb 0xfc 0xfd 0xfe 0xff 0x09 0x0a}"])

self.runCmd("register write xmm0 \"{0xff 0xfe 0xfd 0xfc 0xfb 0xfa 0xf9 "
"0xf8 0xf7 0xf6 0xf5 0xf4 0xf3 0xf2 0xf1 0xf0}\"")
self.match("register read ymm0",
["ymm0 = {0xff 0xfe 0xfd 0xfc 0xfb 0xfa 0xf9 0xf8 0xf7 0xf6 "
"0xf5 0xf4 0xf3 0xf2 0xf1 0xf0 0xb1 0xb2 0xb3 0xb4 0xb5 "
"0xb6 0xb7 0xb8 0xb9 0xba 0xbb 0xbc 0xbd 0xbe 0xbf 0xc0}"])

self.runCmd("register write ymm0h \"{0xef 0xee 0xed 0xec 0xeb 0xea 0xe9 "
"0xe8 0xe7 0xe6 0xe5 0xe4 0xe3 0xe2 0xe1 0xe0}\"")
self.match("register read ymm0",
["ymm0 = {0xff 0xfe 0xfd 0xfc 0xfb 0xfa 0xf9 0xf8 0xf7 0xf6 "
"0xf5 0xf4 0xf3 0xf2 0xf1 0xf0 0xef 0xee 0xed 0xec 0xeb "
"0xea 0xe9 0xe8 0xe7 0xe6 0xe5 0xe4 0xe3 0xe2 0xe1 0xe0}"])

self.runCmd("register write ymm0 \"{0xd0 0xd1 0xd2 0xd3 0xd4 0xd5 0xd6 "
"0xd7 0xd8 0xd9 0xda 0xdb 0xdc 0xdd 0xde 0xdf 0xe0 0xe1 "
"0xe2 0xe3 0xe4 0xe5 0xe6 0xe7 0xe8 0xe9 0xea 0xeb 0xec "
"0xed 0xee 0xef}\"")
self.match("register read ymm0",
["ymm0 = {0xd0 0xd1 0xd2 0xd3 0xd4 0xd5 0xd6 0xd7 0xd8 0xd9 "
"0xda 0xdb 0xdc 0xdd 0xde 0xdf 0xe0 0xe1 0xe2 0xe3 0xe4 "
"0xe5 0xe6 0xe7 0xe8 0xe9 0xea 0xeb 0xec 0xed 0xee 0xef}"])

@skipIfXmlSupportMissing
@skipIfRemote
@skipIfLLVMTargetMissing("AArch64")
Expand Down

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