https://github.com/adrian-prantl created
https://github.com/llvm/llvm-project/pull/119620
This trips UBSAN and probably isn't partiuclarly useful either.
>From 104f0d227f5642bf7a02311482fafb4edc667c67 Mon Sep 17 00:00:00 2001
From: Adrian Prantl <apra...@apple.com>
Date: Wed, 11 Dec 2024 13:57:43 -0800
Subject: [PATCH] [lldb] Disallow left shifts of negative values in the
interpreter
This trips UBSAN and probably isn't partiuclarly useful either.
---
lldb/source/DataFormatters/FormatterBytecode.cpp | 8 +++++---
lldb/unittests/DataFormatter/FormatterBytecodeTest.cpp | 7 +++++--
2 files changed, 10 insertions(+), 5 deletions(-)
diff --git a/lldb/source/DataFormatters/FormatterBytecode.cpp
b/lldb/source/DataFormatters/FormatterBytecode.cpp
index f344fbaff6f02a..e49c7506781875 100644
--- a/lldb/source/DataFormatters/FormatterBytecode.cpp
+++ b/lldb/source/DataFormatters/FormatterBytecode.cpp
@@ -379,7 +379,7 @@ llvm::Error Interpret(std::vector<ControlStackElement>
&control,
BINOP_CHECKZERO(%);
continue;
case op_shl:
-#define SHIFTOP(OP)
\
+#define SHIFTOP(OP, LEFT)
\
{
\
TYPE_CHECK(Any, UInt);
\
uint64_t y = data.Pop<uint64_t>();
\
@@ -390,16 +390,18 @@ llvm::Error Interpret(std::vector<ControlStackElement>
&control,
data.Push(x OP y);
\
} else if (std::holds_alternative<int64_t>(data.back())) {
\
int64_t x = data.Pop<int64_t>();
\
+ if (x < 0 && LEFT)
\
+ return error("left shift of negative value");
\
if (y > 64)
\
return error("shift out of bounds");
\
data.Push(x OP y);
\
} else
\
return error("unsupported data types");
\
}
- SHIFTOP(<<);
+ SHIFTOP(<<, true);
continue;
case op_shr:
- SHIFTOP(<<);
+ SHIFTOP(>>, false);
continue;
case op_and:
BINOP(&);
diff --git a/lldb/unittests/DataFormatter/FormatterBytecodeTest.cpp
b/lldb/unittests/DataFormatter/FormatterBytecodeTest.cpp
index 15d9229de00332..7307db650c1629 100644
--- a/lldb/unittests/DataFormatter/FormatterBytecodeTest.cpp
+++ b/lldb/unittests/DataFormatter/FormatterBytecodeTest.cpp
@@ -147,9 +147,12 @@ TEST_F(FormatterBytecodeTest, ArithOps) {
{
DataStack data;
unsigned char minus_one = 127;
- ASSERT_TRUE(
+ ASSERT_FALSE(
Interpret({op_lit_int, minus_one, op_lit_uint, 2, op_shl}, data));
- ASSERT_EQ(data.Pop<int64_t>(), -4);
+ unsigned char minus_two = 126;
+ ASSERT_TRUE(
+ Interpret({op_lit_int, minus_two, op_lit_uint, 1, op_shr}, data));
+ ASSERT_EQ(data.Pop<int64_t>(), -1);
}
{
DataStack data;
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