[Lldb-commits] [lldb] [lldb] Support custom LLVM formatting for variables (PR #91868)
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lldb-commits at lists.llvm.org
Sat May 11 13:51:09 PDT 2024
llvmbot wrote:
<!--LLVM PR SUMMARY COMMENT-->
@llvm/pr-subscribers-lldb
Author: Dave Lee (kastiglione)
<details>
<summary>Changes</summary>
- **[lldb] Support custom LLVM formatting for variables (#<!-- -->81196)**
- **[lldb] Handle non-existent llvm_format**
---
Full diff: https://github.com/llvm/llvm-project/pull/91868.diff
5 Files Affected:
- (modified) lldb/docs/use/variable.rst (+9)
- (modified) lldb/source/Core/FormatEntity.cpp (+63-10)
- (added) lldb/test/API/functionalities/data-formatter/custom-printf-summary/Makefile (+2)
- (added) lldb/test/API/functionalities/data-formatter/custom-printf-summary/TestCustomSummaryLLVMFormat.py (+20)
- (added) lldb/test/API/functionalities/data-formatter/custom-printf-summary/main.c (+13)
``````````diff
diff --git a/lldb/docs/use/variable.rst b/lldb/docs/use/variable.rst
index 8eaed6405315b..e9175b25336ba 100644
--- a/lldb/docs/use/variable.rst
+++ b/lldb/docs/use/variable.rst
@@ -460,6 +460,15 @@ summary strings, regardless of the format they have applied to their types. To
do that, you can use %format inside an expression path, as in ${var.x->x%u},
which would display the value of x as an unsigned integer.
+Additionally, custom output can be achieved by using an LLVM format string,
+commencing with the ``:`` marker. To illustrate, compare ``${var.byte%x}`` and
+``${var.byte:x-}``. The former uses lldb's builtin hex formatting (``x``),
+which unconditionally inserts a ``0x`` prefix, and also zero pads the value to
+match the size of the type. The latter uses ``llvm::formatv`` formatting
+(``:x-``), and will print only the hex value, with no ``0x`` prefix, and no
+padding. This raw control is useful when composing multiple pieces into a
+larger whole.
+
You can also use some other special format markers, not available for formats
themselves, but which carry a special meaning when used in this context:
diff --git a/lldb/source/Core/FormatEntity.cpp b/lldb/source/Core/FormatEntity.cpp
index ba62e26252591..af316e1044d2a 100644
--- a/lldb/source/Core/FormatEntity.cpp
+++ b/lldb/source/Core/FormatEntity.cpp
@@ -57,6 +57,7 @@
#include "llvm/ADT/STLExtras.h"
#include "llvm/ADT/StringRef.h"
#include "llvm/Support/Compiler.h"
+#include "llvm/Support/Regex.h"
#include "llvm/TargetParser/Triple.h"
#include <cctype>
@@ -658,6 +659,38 @@ static char ConvertValueObjectStyleToChar(
return '\0';
}
+static llvm::Regex LLVMFormatPattern{"x[-+]?\\d*|n|d", llvm::Regex::IgnoreCase};
+
+static bool DumpValueWithLLVMFormat(Stream &s, llvm::StringRef options,
+ ValueObject &valobj) {
+ std::string formatted;
+ std::string llvm_format = ("{0:" + options + "}").str();
+
+ // Options supported by format_provider<T> for integral arithmetic types.
+ // See table in FormatProviders.h.
+
+ auto type_info = valobj.GetTypeInfo();
+ if (type_info & eTypeIsInteger && LLVMFormatPattern.match(options)) {
+ if (type_info & eTypeIsSigned) {
+ bool success = false;
+ int64_t integer = valobj.GetValueAsSigned(0, &success);
+ if (success)
+ formatted = llvm::formatv(llvm_format.data(), integer);
+ } else {
+ bool success = false;
+ uint64_t integer = valobj.GetValueAsUnsigned(0, &success);
+ if (success)
+ formatted = llvm::formatv(llvm_format.data(), integer);
+ }
+ }
+
+ if (formatted.empty())
+ return false;
+
+ s.Write(formatted.data(), formatted.size());
+ return true;
+}
+
static bool DumpValue(Stream &s, const SymbolContext *sc,
const ExecutionContext *exe_ctx,
const FormatEntity::Entry &entry, ValueObject *valobj) {
@@ -728,9 +761,12 @@ static bool DumpValue(Stream &s, const SymbolContext *sc,
return RunScriptFormatKeyword(s, sc, exe_ctx, valobj, entry.string.c_str());
}
- llvm::StringRef subpath(entry.string);
+ auto split = llvm::StringRef(entry.string).split(':');
+ auto subpath = split.first;
+ auto llvm_format = split.second;
+
// simplest case ${var}, just print valobj's value
- if (entry.string.empty()) {
+ if (subpath.empty()) {
if (entry.printf_format.empty() && entry.fmt == eFormatDefault &&
entry.number == ValueObject::eValueObjectRepresentationStyleValue)
was_plain_var = true;
@@ -739,7 +775,7 @@ static bool DumpValue(Stream &s, const SymbolContext *sc,
target = valobj;
} else // this is ${var.something} or multiple .something nested
{
- if (entry.string[0] == '[')
+ if (subpath[0] == '[')
was_var_indexed = true;
ScanBracketedRange(subpath, close_bracket_index,
var_name_final_if_array_range, index_lower,
@@ -747,14 +783,11 @@ static bool DumpValue(Stream &s, const SymbolContext *sc,
Status error;
- const std::string &expr_path = entry.string;
-
- LLDB_LOGF(log, "[Debugger::FormatPrompt] symbol to expand: %s",
- expr_path.c_str());
+ LLDB_LOG(log, "[Debugger::FormatPrompt] symbol to expand: {0}", subpath);
target =
valobj
- ->GetValueForExpressionPath(expr_path.c_str(), &reason_to_stop,
+ ->GetValueForExpressionPath(subpath, &reason_to_stop,
&final_value_type, options, &what_next)
.get();
@@ -883,8 +916,18 @@ static bool DumpValue(Stream &s, const SymbolContext *sc,
}
if (!is_array_range) {
- LLDB_LOGF(log,
- "[Debugger::FormatPrompt] dumping ordinary printable output");
+ if (!llvm_format.empty()) {
+ if (DumpValueWithLLVMFormat(s, llvm_format, *target)) {
+ LLDB_LOGF(log, "dumping using llvm format");
+ return true;
+ } else {
+ LLDB_LOG(
+ log,
+ "empty output using llvm format '{0}' - with type info flags {1}",
+ entry.printf_format, target->GetTypeInfo());
+ }
+ }
+ LLDB_LOGF(log, "dumping ordinary printable output");
return target->DumpPrintableRepresentation(s, val_obj_display,
custom_format);
} else {
@@ -2227,6 +2270,16 @@ static Status ParseInternal(llvm::StringRef &format, Entry &parent_entry,
if (error.Fail())
return error;
+ llvm::StringRef entry_string(entry.string);
+ if (entry_string.contains(':')) {
+ auto [_, llvm_format] = entry_string.split(':');
+ if (!llvm_format.empty() && !LLVMFormatPattern.match(llvm_format)) {
+ error.SetErrorStringWithFormat("invalid llvm format: '%s'",
+ llvm_format.data());
+ return error;
+ }
+ }
+
if (verify_is_thread_id) {
if (entry.type != Entry::Type::ThreadID &&
entry.type != Entry::Type::ThreadProtocolID) {
diff --git a/lldb/test/API/functionalities/data-formatter/custom-printf-summary/Makefile b/lldb/test/API/functionalities/data-formatter/custom-printf-summary/Makefile
new file mode 100644
index 0000000000000..c9319d6e6888a
--- /dev/null
+++ b/lldb/test/API/functionalities/data-formatter/custom-printf-summary/Makefile
@@ -0,0 +1,2 @@
+C_SOURCES := main.c
+include Makefile.rules
diff --git a/lldb/test/API/functionalities/data-formatter/custom-printf-summary/TestCustomSummaryLLVMFormat.py b/lldb/test/API/functionalities/data-formatter/custom-printf-summary/TestCustomSummaryLLVMFormat.py
new file mode 100644
index 0000000000000..d6906a49463ba
--- /dev/null
+++ b/lldb/test/API/functionalities/data-formatter/custom-printf-summary/TestCustomSummaryLLVMFormat.py
@@ -0,0 +1,20 @@
+import lldb
+from lldbsuite.test.lldbtest import *
+import lldbsuite.test.lldbutil as lldbutil
+
+
+class TestCase(TestBase):
+ def test_raw_bytes(self):
+ self.build()
+ lldbutil.run_to_source_breakpoint(self, "break here", lldb.SBFileSpec("main.c"))
+ self.runCmd("type summary add -s '${var.ubyte:x-2}${var.sbyte:x-2}!' Bytes")
+ self.expect("v bytes", substrs=[" = 3001!"])
+
+ def test_bad_format(self):
+ self.build()
+ lldbutil.run_to_source_breakpoint(self, "break here", lldb.SBFileSpec("main.c"))
+ self.expect(
+ "type summary add -s '${var.ubyte:y}!' Bytes",
+ error=True,
+ substrs=["invalid llvm format"],
+ )
diff --git a/lldb/test/API/functionalities/data-formatter/custom-printf-summary/main.c b/lldb/test/API/functionalities/data-formatter/custom-printf-summary/main.c
new file mode 100644
index 0000000000000..4164aff7dbf6f
--- /dev/null
+++ b/lldb/test/API/functionalities/data-formatter/custom-printf-summary/main.c
@@ -0,0 +1,13 @@
+#include <stdint.h>
+#include <stdio.h>
+
+struct Bytes {
+ uint8_t ubyte;
+ int8_t sbyte;
+};
+
+int main() {
+ struct Bytes bytes = {0x30, 0x01};
+ (void)bytes;
+ printf("break here\n");
+}
``````````
</details>
https://github.com/llvm/llvm-project/pull/91868
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