kadircet updated this revision to Diff 305094.
kadircet marked an inline comment as done.
kadircet added a comment.
- Increase width of `B` to prevent integer promotion.
Repository:
rG LLVM Github Monorepo
CHANGES SINCE LAST ACTION
https://reviews.llvm.org/D91405/new/
https://reviews.llvm.org/D91405
Files:
clang-tools-extra/clangd/index/Serialization.cpp
clang-tools-extra/clangd/unittests/SerializationTests.cpp
Index: clang-tools-extra/clangd/unittests/SerializationTests.cpp
===================================================================
--- clang-tools-extra/clangd/unittests/SerializationTests.cpp
+++ clang-tools-extra/clangd/unittests/SerializationTests.cpp
@@ -366,9 +366,9 @@
Pos += FileDigest.size();
// Varints are little-endian base-128 numbers, where the top-bit of each byte
- // indicates whether there are more. 8fffffff7f -> 0xffffffff.
+ // indicates whether there are more. ffffffff0f -> 0xffffffff.
std::string CorruptSrcs =
- (Srcs->Data.take_front(Pos) + llvm::fromHex("8fffffff7f") +
+ (Srcs->Data.take_front(Pos) + llvm::fromHex("ffffffff0f") +
"some_random_garbage")
.str();
Srcs->Data = CorruptSrcs;
Index: clang-tools-extra/clangd/index/Serialization.cpp
===================================================================
--- clang-tools-extra/clangd/index/Serialization.cpp
+++ clang-tools-extra/clangd/index/Serialization.cpp
@@ -21,6 +21,7 @@
#include "llvm/Support/Endian.h"
#include "llvm/Support/Error.h"
#include "llvm/Support/raw_ostream.h"
+#include <cstdint>
#include <vector>
namespace clang {
@@ -81,12 +82,16 @@
uint32_t consumeVar() {
constexpr static uint8_t More = 1 << 7;
- uint8_t B = consume8();
+
+ // Use a 32 bit unsigned here to prevent promotion to signed int (unless
int
+ // is wider than 32 bits).
+ uint32_t B = consume8();
if (LLVM_LIKELY(!(B & More)))
return B;
uint32_t Val = B & ~More;
for (int Shift = 7; B & More && Shift < 32; Shift += 7) {
B = consume8();
+ assert((B & ~More) < (1 << (32 - Shift)) && "Invalid varint encoding");
Val |= (B & ~More) << Shift;
}
return Val;
Index: clang-tools-extra/clangd/unittests/SerializationTests.cpp
===================================================================
--- clang-tools-extra/clangd/unittests/SerializationTests.cpp
+++ clang-tools-extra/clangd/unittests/SerializationTests.cpp
@@ -366,9 +366,9 @@
Pos += FileDigest.size();
// Varints are little-endian base-128 numbers, where the top-bit of each byte
- // indicates whether there are more. 8fffffff7f -> 0xffffffff.
+ // indicates whether there are more. ffffffff0f -> 0xffffffff.
std::string CorruptSrcs =
- (Srcs->Data.take_front(Pos) + llvm::fromHex("8fffffff7f") +
+ (Srcs->Data.take_front(Pos) + llvm::fromHex("ffffffff0f") +
"some_random_garbage")
.str();
Srcs->Data = CorruptSrcs;
Index: clang-tools-extra/clangd/index/Serialization.cpp
===================================================================
--- clang-tools-extra/clangd/index/Serialization.cpp
+++ clang-tools-extra/clangd/index/Serialization.cpp
@@ -21,6 +21,7 @@
#include "llvm/Support/Endian.h"
#include "llvm/Support/Error.h"
#include "llvm/Support/raw_ostream.h"
+#include <cstdint>
#include <vector>
namespace clang {
@@ -81,12 +82,16 @@
uint32_t consumeVar() {
constexpr static uint8_t More = 1 << 7;
- uint8_t B = consume8();
+
+ // Use a 32 bit unsigned here to prevent promotion to signed int (unless int
+ // is wider than 32 bits).
+ uint32_t B = consume8();
if (LLVM_LIKELY(!(B & More)))
return B;
uint32_t Val = B & ~More;
for (int Shift = 7; B & More && Shift < 32; Shift += 7) {
B = consume8();
+ assert((B & ~More) < (1 << (32 - Shift)) && "Invalid varint encoding");
Val |= (B & ~More) << Shift;
}
return Val;
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