kusmour created this revision.
kusmour added reviewers: xiaobai, compnerd.
Herald added a project: LLDB.
Herald added a subscriber: lldb-commits.
Add a function to flatten the nested aggregate type
Repository:
rLLDB LLDB
https://reviews.llvm.org/D62702
Files:
lldb/source/Plugins/ABI/SysV-x86_64/ABISysV_x86_64.cpp
Index: lldb/source/Plugins/ABI/SysV-x86_64/ABISysV_x86_64.cpp
===================================================================
--- lldb/source/Plugins/ABI/SysV-x86_64/ABISysV_x86_64.cpp
+++ lldb/source/Plugins/ABI/SysV-x86_64/ABISysV_x86_64.cpp
@@ -30,6 +30,8 @@
#include "lldb/Utility/RegisterValue.h"
#include "lldb/Utility/Status.h"
+#include <vector>
+
using namespace lldb;
using namespace lldb_private;
@@ -1558,6 +1560,62 @@
return return_valobj_sp;
}
+// The compiler will faltten the nested aggregate type into single
+// layer and push the value to stack
+// This helper function will flatten an aggregate type
+// and return true if it can be returned in register(s) by value
+// return false if the aggregate is in memory
+static bool FlattenAggregateType(
+ ExecutionContext &exe_ctx,
+ CompilerType &return_compiler_type,
+ uint32_t data_byte_offset,
+ std::vector<uint32_t> &aggregate_field_offsets,
+ std::vector<CompilerType> &aggregate_compiler_types) {
+ const uint32_t num_children = return_compiler_type.GetNumFields();
+ for (uint32_t idx = 0; idx < num_children; ++idx) {
+ std::string name;
+ bool is_signed;
+ uint32_t count;
+ bool is_complex;
+
+ const bool transparent_pointers = false;
+ const bool omit_empty_base_classes = true;
+ const bool ignore_array_bounds = false;
+ uint32_t child_byte_size = 0;
+ int32_t child_byte_offset = 0;
+ uint32_t child_bitfield_bit_size = 0;
+ uint32_t child_bitfield_bit_offset = 0;
+ bool child_is_base_class = false;
+ bool child_is_deref_of_parent = false;
+ uint64_t language_flags;
+ CompilerType field_compiler_type =
+ return_compiler_type.GetChildCompilerTypeAtIndex(
+ &exe_ctx, idx, transparent_pointers, omit_empty_base_classes,
+ ignore_array_bounds, name, child_byte_size, child_byte_offset,
+ child_bitfield_bit_size, child_bitfield_bit_offset,
+ child_is_base_class, child_is_deref_of_parent, nullptr,
+ language_flags);
+
+ const uint64_t field_bit_offset = child_byte_offset * 8;
+ uint32_t field_byte_offset = field_bit_offset / 8 + data_byte_offset;
+
+ const uint32_t field_type_flags = field_compiler_type.GetTypeInfo();
+ if (field_compiler_type.IsIntegerOrEnumerationType(is_signed) ||
+ field_compiler_type.IsPointerType() ||
+ field_compiler_type.IsFloatingPointType(count, is_complex)) {
+ aggregate_field_offsets.push_back(field_byte_offset);
+ aggregate_compiler_types.push_back(field_compiler_type);
+ } else if (field_type_flags & eTypeHasChildren) {
+ if (!FlattenAggregateType(exe_ctx, field_compiler_type,
+ field_byte_offset, aggregate_field_offsets,
+ aggregate_compiler_types)) {
+ return false;
+ }
+ }
+ }
+ return true;
+}
+
ValueObjectSP ABISysV_x86_64::GetReturnValueObjectImpl(
Thread &thread, CompilerType &return_compiler_type) const {
ValueObjectSP return_valobj_sp;
@@ -1580,10 +1638,14 @@
if (return_compiler_type.IsAggregateType()) {
Target *target = exe_ctx.GetTargetPtr();
bool is_memory = true;
- if (*bit_width <= 128) {
- ByteOrder target_byte_order = target->GetArchitecture().GetByteOrder();
+ std::vector<uint32_t> aggregate_field_offsets;
+ std::vector<CompilerType> aggregate_compiler_types;
+ if (*bit_width <= 128 && FlattenAggregateType(exe_ctx, return_compiler_type,
+ 0, aggregate_field_offsets,
+ aggregate_compiler_types)) {
+ ByteOrder byte_order = target->GetArchitecture().GetByteOrder();
DataBufferSP data_sp(new DataBufferHeap(16, 0));
- DataExtractor return_ext(data_sp, target_byte_order,
+ DataExtractor return_ext(data_sp, byte_order,
target->GetArchitecture().GetAddressByteSize());
const RegisterInfo *rax_info =
@@ -1613,40 +1675,27 @@
uint32_t integer_bytes =
0; // Tracks how much of the rax/rds registers we've consumed so far
- const uint32_t num_children = return_compiler_type.GetNumFields();
+ // const uint32_t num_children = return_compiler_type.GetNumFields();
+ const uint32_t num_children = aggregate_compiler_types.size();
// Since we are in the small struct regime, assume we are not in memory.
is_memory = false;
-
for (uint32_t idx = 0; idx < num_children; idx++) {
- std::string name;
- uint64_t field_bit_offset = 0;
bool is_signed;
- bool is_complex;
uint32_t count;
+ bool is_complex;
- CompilerType field_compiler_type = return_compiler_type.GetFieldAtIndex(
- idx, name, &field_bit_offset, nullptr, nullptr);
- llvm::Optional<uint64_t> field_bit_width =
- field_compiler_type.GetBitSize(&thread);
-
- // if we don't know the size of the field (e.g. invalid type), just
- // bail out
- if (!field_bit_width || *field_bit_width == 0)
- break;
-
- // If there are any unaligned fields, this is stored in memory.
- if (field_bit_offset % *field_bit_width != 0) {
- is_memory = true;
- break;
- }
+ CompilerType field_compiler_type = aggregate_compiler_types[idx];
+ uint32_t field_byte_width = (uint32_t) (*field_compiler_type.GetByteSize(&thread));
+ uint32_t field_byte_offset = aggregate_field_offsets[idx];
- uint32_t field_byte_width = *field_bit_width / 8;
- uint32_t field_byte_offset = field_bit_offset / 8;
+ uint32_t field_bit_width = field_byte_width * 8;
DataExtractor *copy_from_extractor = nullptr;
uint32_t copy_from_offset = 0;
+ const uint32_t field_type_flags = field_compiler_type.GetTypeInfo();
+
if (field_compiler_type.IsIntegerOrEnumerationType(is_signed) ||
field_compiler_type.IsPointerType()) {
if (integer_bytes < 8) {
@@ -1674,10 +1723,10 @@
}
} else if (field_compiler_type.IsFloatingPointType(count, is_complex)) {
// Structs with long doubles are always passed in memory.
- if (*field_bit_width == 128) {
+ if (field_bit_width == 128) {
is_memory = true;
break;
- } else if (*field_bit_width == 64) {
+ } else if (field_bit_width == 64) {
// These have to be in a single xmm register.
if (fp_bytes == 0)
copy_from_extractor = &xmm0_data;
@@ -1686,7 +1735,7 @@
copy_from_offset = 0;
fp_bytes += field_byte_width;
- } else if (*field_bit_width == 32) {
+ } else if (field_bit_width == 32) {
// This one is kind of complicated. If we are in an "eightbyte"
// with another float, we'll be stuffed into an xmm register with
// it. If we are in an "eightbyte" with one or more ints, then we
@@ -1695,18 +1744,15 @@
if (field_byte_offset % 8 == 0) {
// We are at the beginning of one of the eightbytes, so check the
// next element (if any)
- if (idx == num_children - 1)
+ if (idx == num_children - 1) {
in_gpr = false;
- else {
- uint64_t next_field_bit_offset = 0;
+ } else {
CompilerType next_field_compiler_type =
- return_compiler_type.GetFieldAtIndex(idx + 1, name,
- &next_field_bit_offset,
- nullptr, nullptr);
+ aggregate_compiler_types[idx + 1];
if (next_field_compiler_type.IsIntegerOrEnumerationType(
- is_signed))
+ is_signed)) {
in_gpr = true;
- else {
+ } else {
copy_from_offset = 0;
in_gpr = false;
}
@@ -1715,18 +1761,15 @@
// We are inside of an eightbyte, so see if the field before us
// is floating point: This could happen if somebody put padding
// in the structure.
- if (idx == 0)
+ if (idx == 0) {
in_gpr = false;
- else {
- uint64_t prev_field_bit_offset = 0;
+ } else {
CompilerType prev_field_compiler_type =
- return_compiler_type.GetFieldAtIndex(idx - 1, name,
- &prev_field_bit_offset,
- nullptr, nullptr);
+ aggregate_compiler_types[idx - 1];
if (prev_field_compiler_type.IsIntegerOrEnumerationType(
- is_signed))
+ is_signed)) {
in_gpr = true;
- else {
+ } else {
copy_from_offset = 4;
in_gpr = false;
}
@@ -1759,22 +1802,21 @@
}
}
}
-
// These two tests are just sanity checks. If I somehow get the type
// calculation wrong above it is better to just return nothing than to
// assert or crash.
- if (!copy_from_extractor)
+ if (!copy_from_extractor) {
return return_valobj_sp;
+ }
if (copy_from_offset + field_byte_width >
- copy_from_extractor->GetByteSize())
+ copy_from_extractor->GetByteSize()) {
return return_valobj_sp;
-
+ }
copy_from_extractor->CopyByteOrderedData(
copy_from_offset, field_byte_width,
data_sp->GetBytes() + field_byte_offset, field_byte_width,
- target_byte_order);
+ byte_order);
}
-
if (!is_memory) {
// The result is in our data buffer. Let's make a variable object out
// of it:
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