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[lldb] Make ReadCStringFromMemory default to read from the file-cache. #3856

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Merged
merged 2 commits into from
Feb 3, 2022
Merged

[lldb] Make ReadCStringFromMemory default to read from the file-cache. #3856

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ecd3b66
[lldb] Make ReadCStringFromMemory default to read from the file-cache.
augusto2112 Jan 26, 2022
03a0435
[lldb] Force live memory if we can't read from the file-cache
augusto2112 Feb 1, 2022
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5 changes: 3 additions & 2 deletions lldb/include/lldb/Target/Target.h
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Original file line number Diff line number Diff line change
Expand Up @@ -1067,10 +1067,11 @@ class Target : public std::enable_shared_from_this<Target>,
lldb::addr_t *load_addr_ptr = nullptr);

size_t ReadCStringFromMemory(const Address &addr, std::string &out_str,
Status &error);
Status &error, bool force_live_memory = false);

size_t ReadCStringFromMemory(const Address &addr, char *dst,
size_t dst_max_len, Status &result_error);
size_t dst_max_len, Status &result_error,
bool force_live_memory = false);

size_t ReadScalarIntegerFromMemory(const Address &addr, uint32_t byte_size,
bool is_signed, Scalar &scalar,
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6 changes: 5 additions & 1 deletion lldb/source/Plugins/LanguageRuntime/Swift/LLDBMemoryReader.cpp
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Expand Up @@ -198,7 +198,11 @@ bool LLDBMemoryReader::readString(swift::remote::RemoteAddress address,

Target &target(m_process.GetTarget());
Status error;
target.ReadCStringFromMemory(addr, dest, error);
// We only want to allow the file-cache optimization if we resolved the
// address to section + offset.
const bool force_live_memory =
!readMetadataFromFileCacheEnabled() || !addr.IsSectionOffset();
target.ReadCStringFromMemory(addr, dest, error, force_live_memory);
if (error.Success()) {
auto format_string = [](const std::string &dest) {
StreamString stream;
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12 changes: 7 additions & 5 deletions lldb/source/Target/Target.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -1873,13 +1873,14 @@ size_t Target::ReadMemory(const Address &addr, void *dst, size_t dst_len,
}

size_t Target::ReadCStringFromMemory(const Address &addr, std::string &out_str,
Status &error) {
Status &error, bool force_live_memory) {
char buf[256];
out_str.clear();
addr_t curr_addr = addr.GetLoadAddress(this);
Address address(addr);
while (true) {
size_t length = ReadCStringFromMemory(address, buf, sizeof(buf), error);
size_t length = ReadCStringFromMemory(address, buf, sizeof(buf), error,
force_live_memory);
if (length == 0)
break;
out_str.append(buf, length);
Expand All @@ -1895,7 +1896,8 @@ size_t Target::ReadCStringFromMemory(const Address &addr, std::string &out_str,
}

size_t Target::ReadCStringFromMemory(const Address &addr, char *dst,
size_t dst_max_len, Status &result_error) {
size_t dst_max_len, Status &result_error,
bool force_live_memory) {
size_t total_cstr_len = 0;
if (dst && dst_max_len) {
result_error.Clear();
Expand All @@ -1918,8 +1920,8 @@ size_t Target::ReadCStringFromMemory(const Address &addr, char *dst,
cache_line_size - (curr_addr % cache_line_size);
addr_t bytes_to_read =
std::min<addr_t>(bytes_left, cache_line_bytes_left);
size_t bytes_read =
ReadMemory(address, curr_dst, bytes_to_read, error, true);
size_t bytes_read = ReadMemory(address, curr_dst, bytes_to_read, error,
force_live_memory);

if (bytes_read == 0) {
result_error = error;
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