This revision was automatically updated to reflect the committed changes.
labath marked an inline comment as done.
Closed by commit rGd4381153ea63: [lldb/libc++] Simplify the libc++ string
formatter (authored by labath).
Changed prior to commit:
https://reviews.llvm.org/D129490?vs=443648&id=443849#toc
Repository:
rG LLVM Github Monorepo
CHANGES SINCE LAST ACTION
https://reviews.llvm.org/D129490/new/
https://reviews.llvm.org/D129490
Files:
lldb/source/Plugins/Language/CPlusPlus/LibCxx.cpp
Index: lldb/source/Plugins/Language/CPlusPlus/LibCxx.cpp
===================================================================
--- lldb/source/Plugins/Language/CPlusPlus/LibCxx.cpp
+++ lldb/source/Plugins/Language/CPlusPlus/LibCxx.cpp
@@ -547,101 +547,77 @@
}
/// The field layout in a libc++ string (cap, side, data or data, size, cap).
-enum LibcxxStringLayoutMode {
- eLibcxxStringLayoutModeCSD = 0,
- eLibcxxStringLayoutModeDSC = 1,
- eLibcxxStringLayoutModeInvalid = 0xffff
-};
+namespace {
+enum class StringLayout { CSD, DSC };
+}
/// Determine the size in bytes of \p valobj (a libc++ std::string object) and
/// extract its data payload. Return the size + payload pair.
// TODO: Support big-endian architectures.
static llvm::Optional<std::pair<uint64_t, ValueObjectSP>>
ExtractLibcxxStringInfo(ValueObject &valobj) {
- ValueObjectSP dataval_sp(valobj.GetChildAtIndexPath({0, 0, 0, 0}));
- if (!dataval_sp)
+ ValueObjectSP valobj_r_sp =
+ valobj.GetChildMemberWithName(ConstString("__r_"), /*can_create=*/true);
+ if (!valobj_r_sp)
return {};
- if (!dataval_sp->GetError().Success())
+
+ // __r_ is a compressed_pair of the actual data and the allocator. The data we
+ // want is in the first base class.
+ ValueObjectSP valobj_r_base_sp =
+ valobj_r_sp->GetChildAtIndex(0, /*can_create=*/true);
+ if (!valobj_r_base_sp)
return {};
- ValueObjectSP layout_decider(
- dataval_sp->GetChildAtIndexPath(llvm::ArrayRef<size_t>({0, 0})));
+ ValueObjectSP valobj_rep_sp = valobj_r_base_sp->GetChildMemberWithName(
+ ConstString("__value_"), /*can_create=*/true);
+ if (!valobj_rep_sp)
+ return {};
- // this child should exist
- if (!layout_decider)
+ ValueObjectSP l = valobj_rep_sp->GetChildMemberWithName(ConstString("__l"),
+ /*can_create=*/true);
+ if (!l)
return {};
- ConstString g_data_name("__data_");
- ConstString g_size_name("__size_");
+ StringLayout layout = l->GetIndexOfChildWithName(ConstString("__data_")) == 0
+ ? StringLayout::DSC
+ : StringLayout::CSD;
+
bool short_mode = false; // this means the string is in short-mode and the
// data is stored inline
bool using_bitmasks = true; // Whether the class uses bitmasks for the mode
// flag (pre-D123580).
uint64_t size;
- LibcxxStringLayoutMode layout = (layout_decider->GetName() == g_data_name)
- ? eLibcxxStringLayoutModeDSC
- : eLibcxxStringLayoutModeCSD;
uint64_t size_mode_value = 0;
- ValueObjectSP short_sp(dataval_sp->GetChildAtIndex(1, true));
+ ValueObjectSP short_sp = valobj_rep_sp->GetChildMemberWithName(
+ ConstString("__s"), /*can_create=*/true);
if (!short_sp)
return {};
- ValueObjectSP short_fields_sp;
ValueObjectSP is_long =
short_sp->GetChildMemberWithName(ConstString("__is_long_"), true);
- if (is_long) {
- short_fields_sp = short_sp;
- } else {
- // After D128285, we need to access the `__is_long_` and `__size_` fields
- // from a packed anonymous struct
- short_fields_sp = short_sp->GetChildAtIndex(0, true);
- is_long = short_sp->GetChildMemberWithName(ConstString("__is_long_"), true);
- }
+ ValueObjectSP size_sp =
+ short_sp->GetChildAtNamePath({ConstString("__size_")});
+ if (!size_sp)
+ return {};
if (is_long) {
using_bitmasks = false;
short_mode = !is_long->GetValueAsUnsigned(/*fail_value=*/0);
- if (ValueObjectSP size_member =
- dataval_sp->GetChildAtNamePath({ConstString("__s"), ConstString("__size_")}))
- size = size_member->GetValueAsUnsigned(/*fail_value=*/0);
- else
- return {};
- } else if (layout == eLibcxxStringLayoutModeDSC) {
- llvm::SmallVector<size_t, 3> size_mode_locations[] = {
- {1, 2}, // Post-c3d0205ee771 layout. This was in use for only a brief
- // period, so we can delete it if it becomes a burden.
- {1, 1, 0},
- {1, 1, 1},
- };
- ValueObjectSP size_mode;
- for (llvm::ArrayRef<size_t> loc : size_mode_locations) {
- size_mode = dataval_sp->GetChildAtIndexPath(loc);
- if (size_mode && size_mode->GetName() == g_size_name)
- break;
- }
-
- if (!size_mode)
- return {};
-
- size_mode_value = (size_mode->GetValueAsUnsigned(0));
- short_mode = ((size_mode_value & 0x80) == 0);
+ size = size_sp->GetValueAsUnsigned(/*fail_value=*/0);
} else {
- ValueObjectSP size_mode(dataval_sp->GetChildAtIndexPath({1, 0, 0}));
- if (!size_mode)
- return {};
-
- size_mode_value = (size_mode->GetValueAsUnsigned(0));
- short_mode = ((size_mode_value & 1) == 0);
+ // The string mode is encoded in the size field.
+ size_mode_value = size_sp->GetValueAsUnsigned(0);
+ uint8_t mode_mask = layout == StringLayout::DSC ? 0x80 : 1;
+ short_mode = (size_mode_value & mode_mask) == 0;
}
if (short_mode) {
ValueObjectSP location_sp =
- short_sp->GetChildMemberWithName(g_data_name, true);
+ short_sp->GetChildMemberWithName(ConstString("__data_"), true);
if (using_bitmasks)
- size = (layout == eLibcxxStringLayoutModeDSC)
- ? size_mode_value
- : ((size_mode_value >> 1) % 256);
+ size = (layout == StringLayout::DSC) ? size_mode_value
+ : ((size_mode_value >> 1) % 256);
// When the small-string optimization takes place, the data must fit in the
// inline string buffer (23 bytes on x86_64/Darwin). If it doesn't, it's
@@ -656,10 +632,6 @@
return std::make_pair(size, location_sp);
}
- ValueObjectSP l(dataval_sp->GetChildAtIndex(0, true));
- if (!l)
- return {};
-
// we can use the layout_decider object as the data pointer
ValueObjectSP location_sp =
l->GetChildMemberWithName(ConstString("__data_"), /*can_create=*/true);
@@ -667,19 +639,11 @@
l->GetChildMemberWithName(ConstString("__size_"), /*can_create=*/true);
ValueObjectSP capacity_vo =
l->GetChildMemberWithName(ConstString("__cap_"), /*can_create=*/true);
- if (!capacity_vo) {
- // After D128285, we need to access the `__cap_` field from a packed
- // anonymous struct
- if (ValueObjectSP packed_fields_sp = l->GetChildAtIndex(0, true)) {
- ValueObjectSP capacity_vo = packed_fields_sp->GetChildMemberWithName(
- ConstString("__cap_"), /*can_create=*/true);
- }
- }
if (!size_vo || !location_sp || !capacity_vo)
return {};
size = size_vo->GetValueAsUnsigned(LLDB_INVALID_OFFSET);
uint64_t capacity = capacity_vo->GetValueAsUnsigned(LLDB_INVALID_OFFSET);
- if (!using_bitmasks && layout == eLibcxxStringLayoutModeCSD)
+ if (!using_bitmasks && layout == StringLayout::CSD)
capacity *= 2;
if (size == LLDB_INVALID_OFFSET || capacity == LLDB_INVALID_OFFSET ||
capacity < size)
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