[Lldb-commits] [lldb] [lldb-dap] Support inspecting memory (PR #104317)
Adrian Vogelsgesang via lldb-commits
lldb-commits at lists.llvm.org
Wed Aug 14 15:34:01 PDT 2024
https://github.com/vogelsgesang created https://github.com/llvm/llvm-project/pull/104317
Adds support for the `readMemory` request which allows VS-Code to inspect memory. Also, add `memoryReference` to variablesa and `evaluate` responses, such that the binary view can be opened from the variables view and from the "watch" pane.
>From e01ea18961bbae0fb747b312670946bd768c5d73 Mon Sep 17 00:00:00 2001
From: Adrian Vogelsgesang <avogelsgesang at salesforce.com>
Date: Wed, 14 Aug 2024 11:52:40 +0000
Subject: [PATCH] [lldb-dap] Support inspecting memory
Adds support for the `readMemory` request which allows VS-Code to
inspect memory. Also, add `memoryReference` to variablesa and `evaluate`
responses, such that the binary view can be opened from the variables
view and from the "watch" pane.
---
.../test/tools/lldb-dap/dap_server.py | 15 ++
lldb/test/API/tools/lldb-dap/memory/Makefile | 3 +
.../tools/lldb-dap/memory/TestDAP_memory.py | 121 ++++++++++++
lldb/test/API/tools/lldb-dap/memory/main.cpp | 10 +
lldb/tools/lldb-dap/JSONUtils.cpp | 30 ++-
lldb/tools/lldb-dap/JSONUtils.h | 6 +
lldb/tools/lldb-dap/lldb-dap.cpp | 172 +++++++++++++++++-
7 files changed, 354 insertions(+), 3 deletions(-)
create mode 100644 lldb/test/API/tools/lldb-dap/memory/Makefile
create mode 100644 lldb/test/API/tools/lldb-dap/memory/TestDAP_memory.py
create mode 100644 lldb/test/API/tools/lldb-dap/memory/main.cpp
diff --git a/lldb/packages/Python/lldbsuite/test/tools/lldb-dap/dap_server.py b/lldb/packages/Python/lldbsuite/test/tools/lldb-dap/dap_server.py
index a324af57b61df3..35d792351e6bfc 100644
--- a/lldb/packages/Python/lldbsuite/test/tools/lldb-dap/dap_server.py
+++ b/lldb/packages/Python/lldbsuite/test/tools/lldb-dap/dap_server.py
@@ -691,6 +691,21 @@ def request_disassemble(
for inst in instructions:
self.disassembled_instructions[inst["address"]] = inst
+ def request_read_memory(
+ self, memoryReference, offset, count
+ ):
+ args_dict = {
+ "memoryReference": memoryReference,
+ "offset": offset,
+ "count": count,
+ }
+ command_dict = {
+ "command": "readMemory",
+ "type": "request",
+ "arguments": args_dict,
+ }
+ return self.send_recv(command_dict)
+
def request_evaluate(self, expression, frameIndex=0, threadId=None, context=None):
stackFrame = self.get_stackFrame(frameIndex=frameIndex, threadId=threadId)
if stackFrame is None:
diff --git a/lldb/test/API/tools/lldb-dap/memory/Makefile b/lldb/test/API/tools/lldb-dap/memory/Makefile
new file mode 100644
index 00000000000000..99998b20bcb050
--- /dev/null
+++ b/lldb/test/API/tools/lldb-dap/memory/Makefile
@@ -0,0 +1,3 @@
+CXX_SOURCES := main.cpp
+
+include Makefile.rules
diff --git a/lldb/test/API/tools/lldb-dap/memory/TestDAP_memory.py b/lldb/test/API/tools/lldb-dap/memory/TestDAP_memory.py
new file mode 100644
index 00000000000000..9ff4dbd3138428
--- /dev/null
+++ b/lldb/test/API/tools/lldb-dap/memory/TestDAP_memory.py
@@ -0,0 +1,121 @@
+"""
+Test lldb-dap memory support
+"""
+
+
+from base64 import b64decode
+import dap_server
+from lldbsuite.test.decorators import *
+from lldbsuite.test.lldbtest import *
+from lldbsuite.test import lldbutil
+import lldbdap_testcase
+import os
+
+
+class TestDAP_memory(lldbdap_testcase.DAPTestCaseBase):
+ def test_read_memory(self):
+ """
+ Tests the 'read_memory' request
+ """
+ program = self.getBuildArtifact("a.out")
+ self.build_and_launch(program)
+ source = "main.cpp"
+ self.source_path = os.path.join(os.getcwd(), source)
+ self.set_source_breakpoints(
+ source,
+ [
+ line_number(source, "// Breakpoint"),
+ ],
+ )
+ self.continue_to_next_stop()
+
+ locals = {l['name']: l for l in self.dap_server.get_local_variables()}
+ rawptr_ref = locals['rawptr']['memoryReference']
+
+ # We can read the complete string
+ mem = self.dap_server.request_read_memory(rawptr_ref, 0, 5)["body"]
+ self.assertEqual(mem["unreadableBytes"], 0);
+ self.assertEqual(b64decode(mem["data"]), b"dead\0")
+
+ # Use an offset
+ mem = self.dap_server.request_read_memory(rawptr_ref, 2, 3)["body"]
+ self.assertEqual(b64decode(mem["data"]), b"ad\0")
+
+ # Use a negative offset
+ mem = self.dap_server.request_read_memory(rawptr_ref, -1, 6)["body"]
+ self.assertEqual(b64decode(mem["data"])[1:], b"dead\0")
+
+ # Reads of size 0 are successful
+ # VS-Code sends those in order to check if a `memoryReference` can actually be dereferenced.
+ mem = self.dap_server.request_read_memory(rawptr_ref, 0, 0)
+ self.assertEqual(mem["success"], True)
+ self.assertEqual(mem["body"]["data"], "")
+
+ # Reads at offset 0x0 fail
+ mem = self.dap_server.request_read_memory("0x0", 0, 6)
+ self.assertEqual(mem["success"], False)
+ self.assertTrue(mem["message"].startswith("Unable to read memory: "))
+
+
+ def test_memory_refs_variables(self):
+ """
+ Tests memory references for evaluate
+ """
+ program = self.getBuildArtifact("a.out")
+ self.build_and_launch(program)
+ source = "main.cpp"
+ self.source_path = os.path.join(os.getcwd(), source)
+ self.set_source_breakpoints(
+ source, [line_number(source, "// Breakpoint")],
+ )
+ self.continue_to_next_stop()
+
+ locals = {l['name']: l for l in self.dap_server.get_local_variables()}
+
+ # Pointers should have memory-references
+ self.assertIn("memoryReference", locals['rawptr'].keys())
+ # Smart-pointers also have memory-references
+ self.assertIn("memoryReference", self.dap_server.get_local_variable_child("smartptr", "pointer").keys())
+ # Non-pointers should not have memory-references
+ self.assertNotIn("memoryReference", locals['not_a_ptr'].keys())
+
+
+ def test_memory_refs_evaluate(self):
+ """
+ Tests memory references for evaluate
+ """
+ program = self.getBuildArtifact("a.out")
+ self.build_and_launch(program)
+ source = "main.cpp"
+ self.source_path = os.path.join(os.getcwd(), source)
+ self.set_source_breakpoints(
+ source, [line_number(source, "// Breakpoint")],
+ )
+ self.continue_to_next_stop()
+
+ # Pointers contain memory references
+ self.assertIn("memoryReference", self.dap_server.request_evaluate("rawptr + 1")["body"].keys())
+
+ # Non-pointer expressions don't include a memory reference
+ self.assertNotIn("memoryReference", self.dap_server.request_evaluate("1 + 3")["body"].keys())
+
+
+ def test_memory_refs_set_variable(self):
+ """
+ Tests memory references for `setVariable`
+ """
+ program = self.getBuildArtifact("a.out")
+ self.build_and_launch(program)
+ source = "main.cpp"
+ self.source_path = os.path.join(os.getcwd(), source)
+ self.set_source_breakpoints(
+ source, [line_number(source, "// Breakpoint")],
+ )
+ self.continue_to_next_stop()
+
+ # Pointers contain memory references
+ ptr_value = self.get_local_as_int("rawptr")
+ self.assertIn("memoryReference", self.dap_server.request_setVariable(1, "rawptr", ptr_value + 2)["body"].keys())
+
+ # Non-pointer expressions don't include a memory reference
+ self.assertNotIn("memoryReference", self.dap_server.request_setVariable(1, "not_a_ptr", 42)["body"].keys())
diff --git a/lldb/test/API/tools/lldb-dap/memory/main.cpp b/lldb/test/API/tools/lldb-dap/memory/main.cpp
new file mode 100644
index 00000000000000..95ecde82ea2798
--- /dev/null
+++ b/lldb/test/API/tools/lldb-dap/memory/main.cpp
@@ -0,0 +1,10 @@
+#include <memory>
+#include <iostream>
+
+int main() {
+ int not_a_ptr = 666;
+ const char* rawptr = "dead";
+ std::unique_ptr<int> smartptr(new int(42));
+ // Breakpoint
+ return 0;
+}
diff --git a/lldb/tools/lldb-dap/JSONUtils.cpp b/lldb/tools/lldb-dap/JSONUtils.cpp
index a8b85f55939e17..dc8932d5f3181d 100644
--- a/lldb/tools/lldb-dap/JSONUtils.cpp
+++ b/lldb/tools/lldb-dap/JSONUtils.cpp
@@ -1085,6 +1085,19 @@ std::string VariableDescription::GetResult(llvm::StringRef context) {
return description.trim().str();
}
+lldb::addr_t GetMemoryReference(lldb::SBValue v) {
+ if (!v.GetType().IsPointerType() && !v.GetType().IsArrayType()) {
+ return LLDB_INVALID_ADDRESS;
+ }
+
+ lldb::SBValue deref = v.Dereference();
+ if (!deref.IsValid()) {
+ return LLDB_INVALID_ADDRESS;
+ }
+
+ return deref.GetLoadAddress();
+}
+
// "Variable": {
// "type": "object",
// "description": "A Variable is a name/value pair. Optionally a variable
@@ -1144,8 +1157,16 @@ std::string VariableDescription::GetResult(llvm::StringRef context) {
// can use this optional information to present the
// children in a paged UI and fetch them in chunks."
// }
-//
-//
+// "memoryReference": {
+// "type": "string",
+// "description": "A memory reference associated with this variable.
+// For pointer type variables, this is generally a
+// reference to the memory address contained in the
+// pointer. For executable data, this reference may later
+// be used in a `disassemble` request. This attribute may
+// be returned by a debug adapter if corresponding
+// capability `supportsMemoryReferences` is true."
+// },
// "$__lldb_extensions": {
// "description": "Unofficial extensions to the protocol",
// "properties": {
@@ -1253,6 +1274,11 @@ llvm::json::Value CreateVariable(lldb::SBValue v, int64_t variablesReference,
else
object.try_emplace("variablesReference", (int64_t)0);
+
+ if (lldb::addr_t addr = GetMemoryReference(v); addr != LLDB_INVALID_ADDRESS) {
+ object.try_emplace("memoryReference", "0x" + llvm::utohexstr(addr));
+ }
+
object.try_emplace("$__lldb_extensions", desc.GetVariableExtensionsJSON());
return llvm::json::Value(std::move(object));
}
diff --git a/lldb/tools/lldb-dap/JSONUtils.h b/lldb/tools/lldb-dap/JSONUtils.h
index 1515f5ba2e5f4d..c619712c2c682b 100644
--- a/lldb/tools/lldb-dap/JSONUtils.h
+++ b/lldb/tools/lldb-dap/JSONUtils.h
@@ -411,6 +411,12 @@ struct VariableDescription {
std::string GetResult(llvm::StringRef context);
};
+/// Get the corresponding `memoryReference` for a value.
+///
+/// According to the DAP documentation, the `memoryReference` should
+/// refer to the pointee, not to the address of the pointer itself.
+lldb::addr_t GetMemoryReference(lldb::SBValue v);
+
/// Create a "Variable" object for a LLDB thread object.
///
/// This function will fill in the following keys in the returned
diff --git a/lldb/tools/lldb-dap/lldb-dap.cpp b/lldb/tools/lldb-dap/lldb-dap.cpp
index ea84f31aec3a6c..d138a79d4488e5 100644
--- a/lldb/tools/lldb-dap/lldb-dap.cpp
+++ b/lldb/tools/lldb-dap/lldb-dap.cpp
@@ -9,6 +9,7 @@
#include "DAP.h"
#include "Watchpoint.h"
#include "lldb/API/SBMemoryRegionInfo.h"
+#include "llvm/Support/Base64.h"
#include <cassert>
#include <climits>
@@ -1346,6 +1347,16 @@ void request_completions(const llvm::json::Object &request) {
// present the variables in a paged UI and fetch
// them in chunks."
// }
+// "memoryReference": {
+// "type": "string",
+// "description": "A memory reference to a location appropriate
+// for this result. For pointer type eval
+// results, this is generally a reference to the
+// memory address contained in the pointer. This
+// attribute may be returned by a debug adapter
+// if corresponding capability
+// `supportsMemoryReferences` is true."
+// },
// },
// "required": [ "result", "variablesReference" ]
// }
@@ -1411,6 +1422,10 @@ void request_evaluate(const llvm::json::Object &request) {
} else {
body.try_emplace("variablesReference", (int64_t)0);
}
+ if (lldb::addr_t addr = GetMemoryReference(value);
+ addr != LLDB_INVALID_ADDRESS) {
+ body.try_emplace("memoryReference", "0x" + llvm::utohexstr(addr));
+ }
}
}
response.try_emplace("body", std::move(body));
@@ -1718,6 +1733,8 @@ void request_initialize(const llvm::json::Object &request) {
body.try_emplace("supportsLogPoints", true);
// The debug adapter supports data watchpoints.
body.try_emplace("supportsDataBreakpoints", true);
+ // The debug adapter supports the `readMemory` request.
+ body.try_emplace("supportsReadMemoryRequest", true);
// Put in non-DAP specification lldb specific information.
llvm::json::Object lldb_json;
@@ -3600,8 +3617,12 @@ void request_setVariable(const llvm::json::Object &request) {
if (variable.MightHaveChildren())
newVariablesReference = g_dap.variables.InsertExpandableVariable(
variable, /*is_permanent=*/false);
-
body.try_emplace("variablesReference", newVariablesReference);
+
+ if (lldb::addr_t addr = GetMemoryReference(variable);
+ addr != LLDB_INVALID_ADDRESS) {
+ body.try_emplace("memoryReference", "0x" + llvm::utohexstr(addr));
+ }
} else {
EmplaceSafeString(body, "message", std::string(error.GetCString()));
}
@@ -4028,6 +4049,154 @@ void request_disassemble(const llvm::json::Object &request) {
response.try_emplace("body", std::move(body));
g_dap.SendJSON(llvm::json::Value(std::move(response)));
}
+
+// "ReadMemoryRequest": {
+// "allOf": [ { "$ref": "#/definitions/Request" }, {
+// "type": "object",
+// "description": "Reads bytes from memory at the provided location. Clients
+// should only call this request if the corresponding
+// capability `supportsReadMemoryRequest` is true.",
+// "properties": {
+// "command": {
+// "type": "string",
+// "enum": [ "readMemory" ]
+// },
+// "arguments": {
+// "$ref": "#/definitions/ReadMemoryArguments"
+// }
+// },
+// "required": [ "command", "arguments" ]
+// }]
+// },
+// "ReadMemoryArguments": {
+// "type": "object",
+// "description": "Arguments for `readMemory` request.",
+// "properties": {
+// "memoryReference": {
+// "type": "string",
+// "description": "Memory reference to the base location from which data
+// should be read."
+// },
+// "offset": {
+// "type": "integer",
+// "description": "Offset (in bytes) to be applied to the reference
+// location before reading data. Can be negative."
+// },
+// "count": {
+// "type": "integer",
+// "description": "Number of bytes to read at the specified location and
+// offset."
+// }
+// },
+// "required": [ "memoryReference", "count" ]
+// },
+// "ReadMemoryResponse": {
+// "allOf": [ { "$ref": "#/definitions/Response" }, {
+// "type": "object",
+// "description": "Response to `readMemory` request.",
+// "properties": {
+// "body": {
+// "type": "object",
+// "properties": {
+// "address": {
+// "type": "string",
+// "description": "The address of the first byte of data returned.
+// Treated as a hex value if prefixed with `0x`, or
+// as a decimal value otherwise."
+// },
+// "unreadableBytes": {
+// "type": "integer",
+// "description": "The number of unreadable bytes encountered after
+// the last successfully read byte.\nThis can be
+// used to determine the number of bytes that should
+// be skipped before a subsequent
+// `readMemory` request succeeds."
+// },
+// "data": {
+// "type": "string",
+// "description": "The bytes read from memory, encoded using base64.
+// If the decoded length of `data` is less than the
+// requested `count` in the original `readMemory`
+// request, and `unreadableBytes` is zero or
+// omitted, then the client should assume it's
+// reached the end of readable memory."
+// }
+// },
+// "required": [ "address" ]
+// }
+// }
+// }]
+// },
+void request_readMemory(const llvm::json::Object &request) {
+ llvm::json::Object response;
+ FillResponse(request, response);
+ auto arguments = request.getObject("arguments");
+
+ lldb::SBProcess process = g_dap.target.GetProcess();
+ if (!process.IsValid()) {
+ response["success"] = false;
+ response["message"] = "No process running";
+ g_dap.SendJSON(llvm::json::Value(std::move(response)));
+ return;
+ }
+
+ auto memoryReference = GetString(arguments, "memoryReference");
+ lldb::addr_t addr;
+ if (memoryReference.consumeInteger(0, addr)) {
+ response["success"] = false;
+ response["message"] =
+ "Malformed memory reference: " + memoryReference.str();
+ g_dap.SendJSON(llvm::json::Value(std::move(response)));
+ return;
+ }
+
+ addr += GetSigned(arguments, "offset", 0);
+ const auto requested_count = GetUnsigned(arguments, "count", 0);
+ lldb::SBMemoryRegionInfo region_info;
+ lldb::SBError memRegError = process.GetMemoryRegionInfo(addr, region_info);
+ if (memRegError.Fail()) {
+ response["success"] = false;
+ EmplaceSafeString(response, "message",
+ "Unable to find memory region: " +
+ std::string(memRegError.GetCString()));
+ g_dap.SendJSON(llvm::json::Value(std::move(response)));
+ return;
+ }
+ const auto available_count =
+ std::min(requested_count, region_info.GetRegionEnd() - addr);
+ const auto unavailable_count = requested_count - available_count;
+
+ std::vector<uint8_t> buf;
+ buf.resize(available_count);
+ if (available_count > 0) {
+ lldb::SBError memReadError;
+ auto bytes_read =
+ process.ReadMemory(addr, buf.data(), available_count, memReadError);
+ if (memReadError.Fail()) {
+ response["success"] = false;
+ EmplaceSafeString(response, "message",
+ "Unable to read memory: " +
+ std::string(memReadError.GetCString()));
+ g_dap.SendJSON(llvm::json::Value(std::move(response)));
+ return;
+ }
+ if (bytes_read != available_count) {
+ response["success"] = false;
+ EmplaceSafeString(response, "message", "Unexpected, short read");
+ g_dap.SendJSON(llvm::json::Value(std::move(response)));
+ return;
+ }
+ }
+
+ llvm::json::Object body;
+ std::string formatted_addr = "0x" + llvm::utohexstr(addr);
+ body.try_emplace("address", formatted_addr);
+ body.try_emplace("data", llvm::encodeBase64(buf));
+ body.try_emplace("unreadableBytes", unavailable_count);
+ response.try_emplace("body", std::move(body));
+ g_dap.SendJSON(llvm::json::Value(std::move(response)));
+}
+
// A request used in testing to get the details on all breakpoints that are
// currently set in the target. This helps us to test "setBreakpoints" and
// "setFunctionBreakpoints" requests to verify we have the correct set of
@@ -4078,6 +4247,7 @@ void RegisterRequestCallbacks() {
g_dap.RegisterRequestCallback("threads", request_threads);
g_dap.RegisterRequestCallback("variables", request_variables);
g_dap.RegisterRequestCallback("disassemble", request_disassemble);
+ g_dap.RegisterRequestCallback("readMemory", request_readMemory);
// Custom requests
g_dap.RegisterRequestCallback("compileUnits", request_compileUnits);
g_dap.RegisterRequestCallback("modules", request_modules);
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