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[lldb][AArch64] Invalidate SVG prior to reconfiguring ZA regdef #66768

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Merged
merged 2 commits into from
Oct 25, 2023
Merged

[lldb][AArch64] Invalidate SVG prior to reconfiguring ZA regdef #66768

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8b292d5
[lldb][AArch64] Invalidate SVG prior to reconfiguring ZA regdef
DavidSpickett Aug 22, 2023
f00e970
Also use the invalidates mechanism to link vg and svg.
DavidSpickett Oct 6, 2023
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11 changes: 11 additions & 0 deletions lldb/source/Plugins/Process/Utility/RegisterInfoPOSIX_arm64.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -374,6 +374,17 @@ void RegisterInfoPOSIX_arm64::AddRegSetSME() {
std::make_pair(sme_regnum, m_dynamic_reg_infos.size());
m_dynamic_reg_sets.push_back(g_reg_set_sme_arm64);
m_dynamic_reg_sets.back().registers = m_sme_regnum_collection.data();

// When vg is written during streaming mode, svg will also change, as vg and
// svg in this state are both showing the streaming vector length.
// We model this as vg invalidating svg. In non-streaming mode this doesn't
// happen but to keep things simple we will invalidate svg anyway.
//
// This must be added now, rather than when vg is defined because SME is a
// dynamic set that may or may not be present.
static const uint32_t vg_invalidates[] = {sme_regnum + 1 /*svg*/,
LLDB_INVALID_REGNUM};
m_dynamic_reg_infos[GetRegNumSMESVG()].invalidate_regs = vg_invalidates;
}

uint32_t RegisterInfoPOSIX_arm64::ConfigureVectorLengthSVE(uint32_t sve_vq) {
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5 changes: 5 additions & 0 deletions lldb/source/Plugins/Process/gdb-remote/GDBRemoteRegisterContext.cpp
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Expand Up @@ -783,6 +783,11 @@ void GDBRemoteRegisterContext::AArch64Reconfigure() {
std::optional<uint64_t> svg_reg_value;
const RegisterInfo *svg_reg_info = m_reg_info_sp->GetRegisterInfo("svg");
if (svg_reg_info) {
// When vg is written it is automatically made invalid. Writing vg will also
// change svg if we're in streaming mode but it will not be made invalid
// so do this manually so the following read gets the latest svg value.
SetRegisterIsValid(svg_reg_info, false);

uint32_t svg_reg_num = svg_reg_info->kinds[eRegisterKindLLDB];
uint64_t reg_value = ReadRegisterAsUnsigned(svg_reg_num, fail_value);
if (reg_value != fail_value && reg_value <= 32)
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2 changes: 2 additions & 0 deletions ...commands/register/register/aarch64_za_register/za_dynamic_resize/TestZAThreadedDynamic.py
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Expand Up @@ -125,11 +125,13 @@ def za_test_impl(self, enable_za):
self.runCmd("thread select %d" % (idx + 1))
self.check_za_register(4, 2)
self.runCmd("register write vg 2")
self.check_disabled_za_register(2)

elif stopped_at_line_number == thY_break_line1:
self.runCmd("thread select %d" % (idx + 1))
self.check_za_register(2, 3)
self.runCmd("register write vg 4")
self.check_disabled_za_register(4)

self.runCmd("thread continue 2")
self.runCmd("thread continue 3")
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