https://github.com/labath updated
https://github.com/llvm/llvm-project/pull/104193
>From a537a48c444e9dec3a85241d9726d6f3187a43cf Mon Sep 17 00:00:00 2001
From: Pavel Labath <pa...@labath.sk>
Date: Wed, 14 Aug 2024 19:58:27 +0200
Subject: [PATCH] [WIP] memory find speedup+bugfix
---
lldb/source/Target/Process.cpp | 58 ++++++-------
.../memory/find/TestMemoryFind.py | 10 +++
.../API/functionalities/memory/find/main.cpp | 82 +++++++++++++++++--
3 files changed, 108 insertions(+), 42 deletions(-)
diff --git a/lldb/source/Target/Process.cpp b/lldb/source/Target/Process.cpp
index e3c4f2ee398cc4..4e3d7651a066ec 100644
--- a/lldb/source/Target/Process.cpp
+++ b/lldb/source/Target/Process.cpp
@@ -114,33 +114,6 @@ class ProcessOptionValueProperties
}
};
-class ProcessMemoryIterator {
-public:
- ProcessMemoryIterator(Process &process, lldb::addr_t base)
- : m_process(process), m_base_addr(base) {}
-
- bool IsValid() { return m_is_valid; }
-
- uint8_t operator[](lldb::addr_t offset) {
- if (!IsValid())
- return 0;
-
- uint8_t retval = 0;
- Status error;
- if (0 == m_process.ReadMemory(m_base_addr + offset, &retval, 1, error)) {
- m_is_valid = false;
- return 0;
- }
-
- return retval;
- }
-
-private:
- Process &m_process;
- const lldb::addr_t m_base_addr;
- bool m_is_valid = true;
-};
-
static constexpr OptionEnumValueElement g_follow_fork_mode_values[] = {
{
eFollowParent,
@@ -3368,20 +3341,37 @@ lldb::addr_t Process::FindInMemory(lldb::addr_t low,
lldb::addr_t high,
return LLDB_INVALID_ADDRESS;
std::vector<size_t> bad_char_heuristic(256, size);
- ProcessMemoryIterator iterator(*this, low);
-
for (size_t idx = 0; idx < size - 1; idx++) {
decltype(bad_char_heuristic)::size_type bcu_idx = buf[idx];
bad_char_heuristic[bcu_idx] = size - idx - 1;
}
- for (size_t s = 0; s <= (region_size - size);) {
+
+ llvm::SmallVector<uint8_t, 0> mem;
+ addr_t mem_pos = low;
+ const size_t read_size = std::max<size_t>(size, 0x10000);
+
+ for (addr_t s = low; s <= (high - size);) {
+ if (s + size >= mem.size() + mem_pos) {
+ mem.resize_for_overwrite(read_size);
+ Status error;
+ mem.resize(
+ ReadMemory(s, mem.data(), std::min(mem.size(), high - s), error));
+ mem_pos = s;
+ if (error.Fail()) {
+ MemoryRegionInfo info;
+ error = GetMemoryRegionInfo(s, info);
+ if (error.Fail())
+ return LLDB_INVALID_ADDRESS;
+ s = info.GetRange().GetRangeEnd();
+ continue;
+ }
+ }
int64_t j = size - 1;
- while (j >= 0 && buf[j] == iterator[s + j])
+ while (j >= 0 && buf[j] == mem[s + j - mem_pos])
j--;
if (j < 0)
- return low + s;
- else
- s += bad_char_heuristic[iterator[s + size - 1]];
+ return s;
+ s += bad_char_heuristic[mem[s + size - 1 - mem_pos]];
}
return LLDB_INVALID_ADDRESS;
diff --git a/lldb/test/API/functionalities/memory/find/TestMemoryFind.py
b/lldb/test/API/functionalities/memory/find/TestMemoryFind.py
index 09611cc808777d..a606899498b722 100644
--- a/lldb/test/API/functionalities/memory/find/TestMemoryFind.py
+++ b/lldb/test/API/functionalities/memory/find/TestMemoryFind.py
@@ -79,3 +79,13 @@ def test_memory_find(self):
'memory find -s "nothere" `stringdata` `stringdata+10`',
substrs=["data not found within the range."],
)
+
+ pagesize = self.frame().FindVariable("pagesize").GetValueAsUnsigned()
+ mem_with_holes =
self.frame().FindVariable("mem_with_holes").GetValueAsUnsigned()
+ matches_var = self.frame().FindVariable("matches")
+ self.assertEqual(matches_var.GetNumChildren(), 4)
+ matches = [f'data found at location:
{matches_var.GetChildAtIndex(i).GetValueAsUnsigned():#x}' for i in range(4)]
+ self.expect(
+ 'memory find -c 5 -s "needle" `mem_with_holes`
`mem_with_holes+5*pagesize`',
+ substrs=matches + ["no more matches within the range"],
+ )
diff --git a/lldb/test/API/functionalities/memory/find/main.cpp
b/lldb/test/API/functionalities/memory/find/main.cpp
index e3dcfc762ee0f9..e5525e3ca1f73f 100644
--- a/lldb/test/API/functionalities/memory/find/main.cpp
+++ b/lldb/test/API/functionalities/memory/find/main.cpp
@@ -1,9 +1,75 @@
-#include <stdio.h>
-#include <stdint.h>
-
-int main (int argc, char const *argv[])
-{
- const char* stringdata = "hello world; I like to write text in const char
pointers";
- uint8_t bytedata[] =
{0xAA,0xBB,0xCC,0xDD,0xEE,0xFF,0x00,0x11,0x22,0x33,0x44,0x55,0x66,0x77,0x88,0x99};
- return 0; // break here
+#include <cstdint>
+#include <cstdio>
+#include <cstdlib>
+#include <cstring>
+#include <initializer_list>
+
+#ifdef _WIN32
+#include "Windows.h"
+
+int getpagesize() {
+ SYSTEM_INFO system_info;
+ GetSystemInfo(&system_info);
+ return system_info.dwPageSize;
+}
+
+void *allocate_memory_with_holes() {
+ int pagesize = getpagesize();
+ void *mem = VirtualAlloc(nullptr, 5 * pagesize, MEM_RESERVE, PAGE_NOACCESS);
+ if (!mem) {
+ std::cerr << std::system_category().message(GetLastError()) << std::endl;
+ exit(1);
+ }
+ char *bytes = static_cast<char *>(mem);
+ for (int page : {0, 2, 4}) {
+ if (!VirtualAlloc(bytes + page * pagesize, pagesize, MEM_COMMIT,
+ PAGE_READWRITE)) {
+ std::cerr << std::system_category().message(GetLastError()) << std::endl;
+ exit(1);
+ }
+ }
+ return bytes;
+}
+#else
+#include "sys/mman.h"
+#include "unistd.h"
+
+char *allocate_memory_with_holes() {
+ int pagesize = getpagesize();
+ void *mem = mmap(nullptr, 5 * pagesize, PROT_READ | PROT_WRITE,
+ MAP_PRIVATE | MAP_ANONYMOUS, -1, 0);
+ if (mem == MAP_FAILED) {
+ perror("mmap");
+ exit(1);
+ }
+ char *bytes = static_cast<char *>(mem);
+ for (int page : {1, 3}) {
+ if (munmap(bytes + page * pagesize, pagesize) != 0) {
+ perror("munmap");
+ exit(1);
+ }
+ }
+ return bytes;
+}
+#endif
+
+int main(int argc, char const *argv[]) {
+ const char *stringdata =
+ "hello world; I like to write text in const char pointers";
+ uint8_t bytedata[] = {0xAA, 0xBB, 0xCC, 0xDD, 0xEE, 0xFF, 0x00, 0x11,
+ 0x22, 0x33, 0x44, 0x55, 0x66, 0x77, 0x88, 0x99};
+
+ char *mem_with_holes = allocate_memory_with_holes();
+ int pagesize = getpagesize();
+ char *matches[] = {
+ mem_with_holes, // Beginning of memory
+ mem_with_holes + 2 * pagesize, // After a hole
+ mem_with_holes + 2 * pagesize +
+ pagesize / 2, // Middle of a block, after an existing match.
+ mem_with_holes + 5 * pagesize - 7, // End of memory
+ };
+ for (char *m : matches)
+ strcpy(m, "needle");
+
+ return 0; // break here
}
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