kastiglione created this revision.
kastiglione added reviewers: jingham, aprantl.
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kastiglione requested review of this revision.
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Herald added a subscriber: lldb-commits.
Context: The `expression` command uses artificial variables to store the
expression
result. This result variable is unconditionally kept around after the
expression command
has completed. These variables are known as persistent results. These are the
variables
`$0`, `$1`, etc, that are displayed when running `p` or `expression`.
This change allows users to control whether result variables are persisted, by
introducing a `--persistent-result`/`-C` flag.
Aside: the short flags `p`/`P`/`r`/`R` are all taken, the flag `-C` was chosen
because
the word "cache" also seems apt.
This change keeps the current default behavior, persistent results are created
by
default. This change gives users the ability to opt-out by re-aliasing `p`. For
example:
command unalias p
command alias p expression -C false --
For consistency, this flag is also adopted by `dwim-print`. Of note, if asked,
`dwim-print` will create a persistent result even for frame variables.
Repository:
rG LLVM Github Monorepo
https://reviews.llvm.org/D144230
Files:
lldb/source/Commands/CommandObjectDWIMPrint.cpp
lldb/source/Commands/CommandObjectExpression.cpp
lldb/source/Commands/CommandObjectExpression.h
lldb/source/Commands/Options.td
lldb/source/DataFormatters/ValueObjectPrinter.cpp
Index: lldb/source/DataFormatters/ValueObjectPrinter.cpp
===================================================================
--- lldb/source/DataFormatters/ValueObjectPrinter.cpp
+++ lldb/source/DataFormatters/ValueObjectPrinter.cpp
@@ -425,7 +425,9 @@
if (m_options.m_hide_pointer_value &&
IsPointerValue(m_valobj->GetCompilerType())) {
} else {
- m_stream->Printf(" %s", m_value.c_str());
+ if (!m_options.m_hide_name)
+ m_stream->Write(" ", 1);
+ m_stream->Write(m_value.c_str(), m_value.length());
value_printed = true;
}
}
Index: lldb/source/Commands/Options.td
===================================================================
--- lldb/source/Commands/Options.td
+++ lldb/source/Commands/Options.td
@@ -386,6 +386,11 @@
Arg<"Boolean">,
Desc<"Controls whether the expression can fall back to being JITted if it's "
"not supported by the interpreter (defaults to true).">;
+ def persistent_result : Option<"persistent-result", "C">, Groups<[1,2]>,
+ Arg<"Boolean">,
+ Desc<"Persist expression result in a variable for subsequent use. "
+ "Expression results will be labeled with $-prefixed variables, e.g. $0, "
+ "$1, etc. Defaults to true.">;
}
let Command = "frame diag" in {
Index: lldb/source/Commands/CommandObjectExpression.h
===================================================================
--- lldb/source/Commands/CommandObjectExpression.h
+++ lldb/source/Commands/CommandObjectExpression.h
@@ -53,6 +53,7 @@
lldb::LanguageType language;
LanguageRuntimeDescriptionDisplayVerbosity m_verbosity;
LazyBool auto_apply_fixits;
+ bool suppress_persistent_result;
};
CommandObjectExpression(CommandInterpreter &interpreter);
Index: lldb/source/Commands/CommandObjectExpression.cpp
===================================================================
--- lldb/source/Commands/CommandObjectExpression.cpp
+++ lldb/source/Commands/CommandObjectExpression.cpp
@@ -146,6 +146,21 @@
break;
}
+ case 'C': {
+ // 'C' for "caching", since both 'P' and 'p' for persist are taken. Both 'R'
+ // flags are taken too.
+ bool success;
+ bool persist_result =
+ OptionArgParser::ToBoolean(option_arg, true, &success);
+ if (success)
+ suppress_persistent_result = !persist_result;
+ else
+ error.SetErrorStringWithFormat(
+ "could not convert \"%s\" to a boolean value.",
+ option_arg.str().c_str());
+ break;
+ }
+
default:
llvm_unreachable("Unimplemented option");
}
@@ -174,6 +189,7 @@
auto_apply_fixits = eLazyBoolCalculate;
top_level = false;
allow_jit = true;
+ suppress_persistent_result = false;
}
llvm::ArrayRef<OptionDefinition>
@@ -186,7 +202,9 @@
const Target &target, bool use_objc, lldb::DynamicValueType use_dynamic) {
EvaluateExpressionOptions options;
options.SetCoerceToId(use_objc);
- if (m_verbosity == eLanguageRuntimeDescriptionDisplayVerbosityCompact)
+ if (suppress_persistent_result)
+ options.SetSuppressPersistentResult(true);
+ else if (m_verbosity == eLanguageRuntimeDescriptionDisplayVerbosityCompact)
options.SetSuppressPersistentResult(use_objc);
options.SetUnwindOnError(unwind_on_error);
options.SetIgnoreBreakpoints(ignore_breakpoints);
@@ -438,6 +456,8 @@
DumpValueObjectOptions options(m_varobj_options.GetAsDumpOptions(
m_command_options.m_verbosity, format));
+ if (m_command_options.suppress_persistent_result)
+ options.SetHideName(true);
options.SetVariableFormatDisplayLanguage(
result_valobj_sp->GetPreferredDisplayLanguage());
Index: lldb/source/Commands/CommandObjectDWIMPrint.cpp
===================================================================
--- lldb/source/Commands/CommandObjectDWIMPrint.cpp
+++ lldb/source/Commands/CommandObjectDWIMPrint.cpp
@@ -64,11 +64,16 @@
DumpValueObjectOptions dump_options = m_varobj_options.GetAsDumpOptions(
m_expr_options.m_verbosity, m_format_options.GetFormat());
+ if (m_expr_options.suppress_persistent_result)
+ dump_options.SetHideName(true);
// First, try `expr` as the name of a frame variable.
if (StackFrame *frame = m_exe_ctx.GetFramePtr()) {
auto valobj_sp = frame->FindVariable(ConstString(expr));
if (valobj_sp && valobj_sp->GetError().Success()) {
+ if (!m_expr_options.suppress_persistent_result)
+ valobj_sp = valobj_sp->Persist();
+
if (verbosity == eDWIMPrintVerbosityFull) {
StringRef flags;
if (args.HasArgs())
@@ -76,6 +81,7 @@
result.AppendMessageWithFormatv("note: ran `frame variable {0}{1}`",
flags, expr);
}
+
valobj_sp->Dump(result.GetOutputStream(), dump_options);
result.SetStatus(eReturnStatusSuccessFinishResult);
return true;
@@ -103,6 +109,7 @@
result.AppendMessageWithFormatv("note: ran `expression {0}{1}`", flags,
expr);
}
+
valobj_sp->Dump(result.GetOutputStream(), dump_options);
result.SetStatus(eReturnStatusSuccessFinishResult);
return true;
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