[Lldb-commits] [lldb] [RISCV][LLDB] Add RISC-V Architecture plugin for trap validation (PR #207675)
Sudharsan Veeravalli via lldb-commits
lldb-commits at lists.llvm.org
Mon Jul 6 02:28:17 PDT 2026
https://github.com/svs-quic updated https://github.com/llvm/llvm-project/pull/207675
>From a921acec8a4e4b577066372ce3f8511d66d18bbe Mon Sep 17 00:00:00 2001
From: Sudharsan Veeravalli <svs at qti.qualcomm.com>
Date: Mon, 6 Jul 2026 12:52:43 +0530
Subject: [PATCH 1/2] [RISCV][LLDB] Add RISC-V Architecture plugin for trap
validation
---
.../Plugins/Architecture/CMakeLists.txt | 1 +
.../Architecture/RISCV/ArchitectureRISCV.cpp | 46 +++++++++++
.../Architecture/RISCV/ArchitectureRISCV.h | 36 +++++++++
.../Plugins/Architecture/RISCV/CMakeLists.txt | 7 ++
lldb/unittests/Architecture/CMakeLists.txt | 1 +
.../RISCV/ArchitectureRISCVTest.cpp | 80 +++++++++++++++++++
.../Architecture/RISCV/CMakeLists.txt | 11 +++
lldb/unittests/CMakeLists.txt | 1 +
8 files changed, 183 insertions(+)
create mode 100644 lldb/source/Plugins/Architecture/RISCV/ArchitectureRISCV.cpp
create mode 100644 lldb/source/Plugins/Architecture/RISCV/ArchitectureRISCV.h
create mode 100644 lldb/source/Plugins/Architecture/RISCV/CMakeLists.txt
create mode 100644 lldb/unittests/Architecture/CMakeLists.txt
create mode 100644 lldb/unittests/Architecture/RISCV/ArchitectureRISCVTest.cpp
create mode 100644 lldb/unittests/Architecture/RISCV/CMakeLists.txt
diff --git a/lldb/source/Plugins/Architecture/CMakeLists.txt b/lldb/source/Plugins/Architecture/CMakeLists.txt
index 0f898ef5116e9..93288ea5841db 100644
--- a/lldb/source/Plugins/Architecture/CMakeLists.txt
+++ b/lldb/source/Plugins/Architecture/CMakeLists.txt
@@ -4,3 +4,4 @@ add_subdirectory(Arm)
add_subdirectory(Mips)
add_subdirectory(PPC64)
add_subdirectory(AArch64)
+add_subdirectory(RISCV)
diff --git a/lldb/source/Plugins/Architecture/RISCV/ArchitectureRISCV.cpp b/lldb/source/Plugins/Architecture/RISCV/ArchitectureRISCV.cpp
new file mode 100644
index 0000000000000..f56a0712981a9
--- /dev/null
+++ b/lldb/source/Plugins/Architecture/RISCV/ArchitectureRISCV.cpp
@@ -0,0 +1,46 @@
+//===-- ArchitectureRISCV.cpp ---------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#include "Plugins/Architecture/RISCV/ArchitectureRISCV.h"
+#include "lldb/Core/PluginManager.h"
+#include "lldb/Utility/ArchSpec.h"
+
+#include <algorithm>
+
+using namespace lldb_private;
+
+LLDB_PLUGIN_DEFINE(ArchitectureRISCV)
+
+void ArchitectureRISCV::Initialize() {
+ PluginManager::RegisterPlugin(GetPluginNameStatic(),
+ "RISC-V-specific algorithms",
+ &ArchitectureRISCV::Create);
+}
+
+void ArchitectureRISCV::Terminate() {
+ PluginManager::UnregisterPlugin(&ArchitectureRISCV::Create);
+}
+
+std::unique_ptr<Architecture> ArchitectureRISCV::Create(const ArchSpec &arch) {
+ auto machine = arch.GetMachine();
+ if (machine != llvm::Triple::riscv32 && machine != llvm::Triple::riscv64)
+ return nullptr;
+ return std::unique_ptr<Architecture>(new ArchitectureRISCV());
+}
+
+bool ArchitectureRISCV::IsValidTrapInstruction(
+ llvm::ArrayRef<uint8_t> reference, llvm::ArrayRef<uint8_t> observed) const {
+ // RISC-V has only two trap encodings here: 16-bit C.EBREAK or 32-bit EBREAK.
+ // These instructions don't have any operands so check that the reference and
+ // exact bytes match.
+ if ((reference.size() != 2 && reference.size() != 4) ||
+ reference.size() > observed.size())
+ return false;
+
+ return std::equal(reference.begin(), reference.end(), observed.begin());
+}
diff --git a/lldb/source/Plugins/Architecture/RISCV/ArchitectureRISCV.h b/lldb/source/Plugins/Architecture/RISCV/ArchitectureRISCV.h
new file mode 100644
index 0000000000000..0a97411a25f76
--- /dev/null
+++ b/lldb/source/Plugins/Architecture/RISCV/ArchitectureRISCV.h
@@ -0,0 +1,36 @@
+//===-- ArchitectureRISCV.h -------------------------------------*- C++ -*-===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef LLDB_SOURCE_PLUGINS_ARCHITECTURE_RISCV_ARCHITECTURERISCV_H
+#define LLDB_SOURCE_PLUGINS_ARCHITECTURE_RISCV_ARCHITECTURERISCV_H
+
+#include "lldb/Core/Architecture.h"
+
+namespace lldb_private {
+
+class ArchitectureRISCV : public Architecture {
+public:
+ static llvm::StringRef GetPluginNameStatic() { return "riscv"; }
+ static void Initialize();
+ static void Terminate();
+
+ llvm::StringRef GetPluginName() override { return GetPluginNameStatic(); }
+
+ void OverrideStopInfo(Thread &thread) const override {}
+
+ bool IsValidTrapInstruction(llvm::ArrayRef<uint8_t> reference,
+ llvm::ArrayRef<uint8_t> observed) const override;
+
+private:
+ static std::unique_ptr<Architecture> Create(const ArchSpec &arch);
+ ArchitectureRISCV() = default;
+};
+
+} // namespace lldb_private
+
+#endif // LLDB_SOURCE_PLUGINS_ARCHITECTURE_RISCV_ARCHITECTURERISCV_H
diff --git a/lldb/source/Plugins/Architecture/RISCV/CMakeLists.txt b/lldb/source/Plugins/Architecture/RISCV/CMakeLists.txt
new file mode 100644
index 0000000000000..443b948179e63
--- /dev/null
+++ b/lldb/source/Plugins/Architecture/RISCV/CMakeLists.txt
@@ -0,0 +1,7 @@
+add_lldb_library(lldbPluginArchitectureRISCV PLUGIN
+ ArchitectureRISCV.cpp
+
+ LINK_LIBS
+ lldbCore
+ lldbUtility
+ )
diff --git a/lldb/unittests/Architecture/CMakeLists.txt b/lldb/unittests/Architecture/CMakeLists.txt
new file mode 100644
index 0000000000000..4e66d7aaa260d
--- /dev/null
+++ b/lldb/unittests/Architecture/CMakeLists.txt
@@ -0,0 +1 @@
+add_subdirectory(RISCV)
diff --git a/lldb/unittests/Architecture/RISCV/ArchitectureRISCVTest.cpp b/lldb/unittests/Architecture/RISCV/ArchitectureRISCVTest.cpp
new file mode 100644
index 0000000000000..619bc5696f861
--- /dev/null
+++ b/lldb/unittests/Architecture/RISCV/ArchitectureRISCVTest.cpp
@@ -0,0 +1,80 @@
+//===-- ArchitectureRISCVTest.cpp -----------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#include "Plugins/Architecture/RISCV/ArchitectureRISCV.h"
+#include "lldb/Core/Architecture.h"
+#include "lldb/Core/PluginManager.h"
+#include "lldb/Utility/ArchSpec.h"
+
+#include "gtest/gtest.h"
+
+using namespace lldb_private;
+
+class ArchitectureRISCVTest : public testing::Test {
+protected:
+ static void SetUpTestSuite() { ArchitectureRISCV::Initialize(); }
+ static void TearDownTestSuite() { ArchitectureRISCV::Terminate(); }
+};
+
+TEST_F(ArchitectureRISCVTest, CreatesPluginForRISCVTargets) {
+ EXPECT_TRUE(PluginManager::CreateArchitectureInstance(
+ ArchSpec("riscv32-unknown-unknown-elf")));
+ EXPECT_TRUE(PluginManager::CreateArchitectureInstance(
+ ArchSpec("riscv64-unknown-unknown-elf")));
+ EXPECT_FALSE(PluginManager::CreateArchitectureInstance(
+ ArchSpec("x86_64-unknown-unknown-elf")));
+}
+
+TEST_F(ArchitectureRISCVTest, ValidatesEBreak) {
+ std::unique_ptr<Architecture> arch =
+ PluginManager::CreateArchitectureInstance(
+ ArchSpec("riscv32-unknown-unknown-elf"));
+ ASSERT_TRUE(arch);
+
+ const uint8_t ebreak[] = {0x73, 0x00, 0x10, 0x00};
+ const uint8_t ebreak_with_extra_bytes[] = {0x73, 0x00, 0x10,
+ 0x00, 0xff, 0xff};
+ const uint8_t wrong_immediate[] = {0x73, 0x00, 0x20, 0x00};
+ const uint8_t truncated_ebreak[] = {0x73, 0x00};
+ const llvm::ArrayRef<uint8_t> empty_reference;
+ const uint8_t bad_size_reference[] = {0x73, 0x00, 0x10};
+
+ EXPECT_TRUE(arch->IsValidTrapInstruction(ebreak, ebreak));
+ EXPECT_TRUE(arch->IsValidTrapInstruction(ebreak, ebreak_with_extra_bytes));
+ EXPECT_FALSE(arch->IsValidTrapInstruction(ebreak, wrong_immediate));
+ EXPECT_FALSE(arch->IsValidTrapInstruction(ebreak, truncated_ebreak));
+ EXPECT_FALSE(arch->IsValidTrapInstruction(empty_reference, ebreak));
+ EXPECT_FALSE(arch->IsValidTrapInstruction(bad_size_reference, ebreak));
+}
+
+TEST_F(ArchitectureRISCVTest, ValidatesCompressedEBreak) {
+ std::unique_ptr<Architecture> arch =
+ PluginManager::CreateArchitectureInstance(
+ ArchSpec("riscv64-unknown-unknown-elf"));
+ ASSERT_TRUE(arch);
+
+ const uint8_t compressed_ebreak[] = {0x02, 0x90};
+ const uint8_t compressed_ebreak_with_extra_bytes[] = {0x02, 0x90, 0xff, 0xff};
+ const uint8_t compressed_unimp[] = {0x00, 0x00};
+ const uint8_t truncated_compressed_ebreak[] = {0x02};
+ const llvm::ArrayRef<uint8_t> empty_reference;
+ const uint8_t bad_size_reference[] = {0x02, 0x90, 0xff};
+
+ EXPECT_TRUE(
+ arch->IsValidTrapInstruction(compressed_ebreak, compressed_ebreak));
+ EXPECT_TRUE(arch->IsValidTrapInstruction(compressed_ebreak,
+ compressed_ebreak_with_extra_bytes));
+ EXPECT_FALSE(
+ arch->IsValidTrapInstruction(empty_reference, compressed_ebreak));
+ EXPECT_FALSE(
+ arch->IsValidTrapInstruction(bad_size_reference, compressed_ebreak));
+ EXPECT_FALSE(
+ arch->IsValidTrapInstruction(compressed_ebreak, compressed_unimp));
+ EXPECT_FALSE(arch->IsValidTrapInstruction(compressed_ebreak,
+ truncated_compressed_ebreak));
+}
diff --git a/lldb/unittests/Architecture/RISCV/CMakeLists.txt b/lldb/unittests/Architecture/RISCV/CMakeLists.txt
new file mode 100644
index 0000000000000..f8e75bd423e13
--- /dev/null
+++ b/lldb/unittests/Architecture/RISCV/CMakeLists.txt
@@ -0,0 +1,11 @@
+if ("RISCV" IN_LIST LLVM_TARGETS_TO_BUILD)
+ add_lldb_unittest(ArchitectureRISCVTests
+ ArchitectureRISCVTest.cpp
+
+ LINK_COMPONENTS
+ Support
+ LINK_LIBS
+ lldbCore
+ lldbPluginArchitectureRISCV
+ lldbUtility)
+endif()
diff --git a/lldb/unittests/CMakeLists.txt b/lldb/unittests/CMakeLists.txt
index 6ce3643bc65be..b0b7f68a7dcd6 100644
--- a/lldb/unittests/CMakeLists.txt
+++ b/lldb/unittests/CMakeLists.txt
@@ -77,6 +77,7 @@ if (NOT CMAKE_SYSTEM_NAME MATCHES "Windows")
add_subdirectory(DAP)
endif()
add_subdirectory(ABI)
+add_subdirectory(Architecture)
add_subdirectory(Breakpoint)
add_subdirectory(Callback)
add_subdirectory(Core)
>From f6b3aedc3889e75101eecb3f4a19b3a0287ebd94 Mon Sep 17 00:00:00 2001
From: Sudharsan Veeravalli <svs at qti.qualcomm.com>
Date: Mon, 6 Jul 2026 14:50:45 +0530
Subject: [PATCH 2/2] Simplify return and correct comment
---
.../source/Plugins/Architecture/RISCV/ArchitectureRISCV.cpp | 6 ++----
1 file changed, 2 insertions(+), 4 deletions(-)
diff --git a/lldb/source/Plugins/Architecture/RISCV/ArchitectureRISCV.cpp b/lldb/source/Plugins/Architecture/RISCV/ArchitectureRISCV.cpp
index f56a0712981a9..d135e6702d1ad 100644
--- a/lldb/source/Plugins/Architecture/RISCV/ArchitectureRISCV.cpp
+++ b/lldb/source/Plugins/Architecture/RISCV/ArchitectureRISCV.cpp
@@ -10,8 +10,6 @@
#include "lldb/Core/PluginManager.h"
#include "lldb/Utility/ArchSpec.h"
-#include <algorithm>
-
using namespace lldb_private;
LLDB_PLUGIN_DEFINE(ArchitectureRISCV)
@@ -37,10 +35,10 @@ bool ArchitectureRISCV::IsValidTrapInstruction(
llvm::ArrayRef<uint8_t> reference, llvm::ArrayRef<uint8_t> observed) const {
// RISC-V has only two trap encodings here: 16-bit C.EBREAK or 32-bit EBREAK.
// These instructions don't have any operands so check that the reference and
- // exact bytes match.
+ // observed bytes match.
if ((reference.size() != 2 && reference.size() != 4) ||
reference.size() > observed.size())
return false;
- return std::equal(reference.begin(), reference.end(), observed.begin());
+ return reference == observed.take_front(reference.size());
}
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