[Lldb-commits] [lldb] [lldb] Fix "in function" detection in "thread until" (PR #123622)
Pavel Labath via lldb-commits
lldb-commits at lists.llvm.org
Mon Jan 20 08:31:33 PST 2025
https://github.com/labath updated https://github.com/llvm/llvm-project/pull/123622
>From 0a80b7a54b49de65758ab48acdb6d92f9b674d71 Mon Sep 17 00:00:00 2001
From: Pavel Labath <pavel at labath.sk>
Date: Mon, 20 Jan 2025 15:03:14 +0100
Subject: [PATCH 1/3] [lldb] Fix "in function" detection in "thread until"
The implementation has an optimization which detects the range of line
table entries covered by the function and then only searches for a
matching line between them.
This optimization was interfering with the logic for detecting whether a
line belongs to the function because the first call to FindLineEntry was
made with exact=false, which meant that if the function did not contain
any exact matches, we would just pick the closest line number in that
range, even if it was very far away.
This patch fixes that by first attempting an inexact search across the
entire line table, and then use the (potentially inexact) result of that
for searching within the function. This makes the optimization a less
effective, but I don't think we can differentiate between a line that
belongs to the function (but doesn't have any code) and a line outside
the function without that.
The patch also avoids the use of (deprecated) Function::GetAddressRange
by iterating over the GetAddressRanges result to find the full range of
line entries for the function.
---
lldb/source/Commands/CommandObjectThread.cpp | 57 ++++++++++---------
.../thread/step_until/TestStepUntil.py | 38 ++++++++++++-
2 files changed, 65 insertions(+), 30 deletions(-)
diff --git a/lldb/source/Commands/CommandObjectThread.cpp b/lldb/source/Commands/CommandObjectThread.cpp
index 4e2c4c1126bc3fe..829abb8c5839bbc 100644
--- a/lldb/source/Commands/CommandObjectThread.cpp
+++ b/lldb/source/Commands/CommandObjectThread.cpp
@@ -959,7 +959,6 @@ class CommandObjectThreadUntil : public CommandObjectParsed {
}
LineEntry function_start;
- uint32_t index_ptr = 0, end_ptr = UINT32_MAX;
std::vector<addr_t> address_list;
// Find the beginning & end index of the function, but first make
@@ -970,19 +969,22 @@ class CommandObjectThreadUntil : public CommandObjectParsed {
return;
}
- AddressRange fun_addr_range = sc.function->GetAddressRange();
- Address fun_start_addr = fun_addr_range.GetBaseAddress();
- line_table->FindLineEntryByAddress(fun_start_addr, function_start,
- &index_ptr);
- Address fun_end_addr(fun_start_addr.GetSection(),
- fun_start_addr.GetOffset() +
- fun_addr_range.GetByteSize());
+ uint32_t lowest_func_idx = UINT32_MAX;
+ uint32_t highest_func_idx = 0;
+ for (AddressRange range : sc.function->GetAddressRanges()) {
+ uint32_t idx;
+ LineEntry unused;
+ Address addr = range.GetBaseAddress();
+ if (line_table->FindLineEntryByAddress(addr, unused, &idx))
+ lowest_func_idx = std::min(lowest_func_idx, idx);
- bool all_in_function = true;
+ addr.Slide(range.GetByteSize());
+ if (line_table->FindLineEntryByAddress(addr, unused, &idx))
+ highest_func_idx = std::max(highest_func_idx, idx);
+ }
- line_table->FindLineEntryByAddress(fun_end_addr, function_start,
- &end_ptr);
+ bool found_something = false;
// Since not all source lines will contribute code, check if we are
// setting the breakpoint on the exact line number or the nearest
@@ -991,14 +993,15 @@ class CommandObjectThreadUntil : public CommandObjectParsed {
for (uint32_t line_number : line_numbers) {
LineEntry line_entry;
bool exact = false;
- uint32_t start_idx_ptr = index_ptr;
- start_idx_ptr = sc.comp_unit->FindLineEntry(
- index_ptr, line_number, nullptr, exact, &line_entry);
- if (start_idx_ptr != UINT32_MAX)
- line_number = line_entry.line;
+ if (sc.comp_unit->FindLineEntry(0, line_number, nullptr, exact,
+ &line_entry) == UINT32_MAX)
+ continue;
+
+ found_something = true;
+ line_number = line_entry.line;
exact = true;
- start_idx_ptr = index_ptr;
- while (start_idx_ptr <= end_ptr) {
+ uint32_t start_idx_ptr = lowest_func_idx;
+ while (start_idx_ptr <= highest_func_idx) {
start_idx_ptr = sc.comp_unit->FindLineEntry(
start_idx_ptr, line_number, nullptr, exact, &line_entry);
if (start_idx_ptr == UINT32_MAX)
@@ -1007,29 +1010,29 @@ class CommandObjectThreadUntil : public CommandObjectParsed {
addr_t address =
line_entry.range.GetBaseAddress().GetLoadAddress(target);
if (address != LLDB_INVALID_ADDRESS) {
- if (fun_addr_range.ContainsLoadAddress(address, target))
+ AddressRange unused;
+ if (sc.function->GetRangeContainingLoadAddress(address, *target,
+ unused))
address_list.push_back(address);
- else
- all_in_function = false;
}
start_idx_ptr++;
}
}
for (lldb::addr_t address : m_options.m_until_addrs) {
- if (fun_addr_range.ContainsLoadAddress(address, target))
+ AddressRange unused;
+ if (sc.function->GetRangeContainingLoadAddress(address, *target,
+ unused))
address_list.push_back(address);
- else
- all_in_function = false;
}
if (address_list.empty()) {
- if (all_in_function)
+ if (found_something)
result.AppendErrorWithFormat(
- "No line entries matching until target.\n");
+ "Until target outside of the current function.\n");
else
result.AppendErrorWithFormat(
- "Until target outside of the current function.\n");
+ "No line entries matching until target.\n");
return;
}
diff --git a/lldb/test/API/functionalities/thread/step_until/TestStepUntil.py b/lldb/test/API/functionalities/thread/step_until/TestStepUntil.py
index 1fbb404aeae58b5..9e2588dc61c0075 100644
--- a/lldb/test/API/functionalities/thread/step_until/TestStepUntil.py
+++ b/lldb/test/API/functionalities/thread/step_until/TestStepUntil.py
@@ -16,9 +16,18 @@ def setUp(self):
self.less_than_two = line_number("main.c", "Less than 2")
self.greater_than_two = line_number("main.c", "Greater than or equal to 2.")
self.back_out_in_main = line_number("main.c", "Back out in main")
+ self.in_foo = line_number("main.c", "In foo")
+
+ def _build_dict_for_discontinuity(self):
+ return dict(
+ CFLAGS_EXTRAS="-funique-basic-block-section-names "
+ + "-ffunction-sections -fbasic-block-sections=list="
+ + self.getSourcePath("function.list"),
+ LD_EXTRAS="-Wl,--script=" + self.getSourcePath("symbol.order"),
+ )
- def common_setup(self, args):
- self.build()
+ def _common_setup(self, build_dict, args):
+ self.build(dictionary=build_dict)
exe = self.getBuildArtifact("a.out")
target = self.dbg.CreateTarget(exe)
@@ -45,7 +54,7 @@ def common_setup(self, args):
return thread
def do_until(self, args, until_lines, expected_linenum):
- thread = self.common_setup(args)
+ thread = self._common_setup(None, args)
cmd_interp = self.dbg.GetCommandInterpreter()
ret_obj = lldb.SBCommandReturnObject()
@@ -88,3 +97,26 @@ def test_missing_one(self):
self.do_until(
["foo", "bar", "baz"], [self.less_than_two], self.back_out_in_main
)
+
+ @no_debug_info_test
+ def test_bad_line(self):
+ """Test that we get an error if attempting to step outside the current
+ function"""
+ thread = self._common_setup(None, None)
+ self.expect(f"thread until {self.in_foo}",
+ substrs=["Until target outside of the current function"],
+ error=True)
+
+ @no_debug_info_test
+ @skipIf(oslist=lldbplatformutil.getDarwinOSTriples() + ["windows"])
+ @skipIf(archs=no_match(["x86_64", "aarch64"]))
+ def test_bad_line_discontinuous(self):
+ """Test that we get an error if attempting to step outside the current
+ function -- and the function is discontinuous"""
+ self.build(dictionary=self._build_dict_for_discontinuity())
+ _, _, thread, _ = lldbutil.run_to_source_breakpoint(
+ self, "At the start", lldb.SBFileSpec(self.main_source)
+ )
+ self.expect(f"thread until {self.in_foo}",
+ substrs=["Until target outside of the current function"],
+ error=True)
>From dbecc09b173e8fc3a196617d90f4f3624df4b52a Mon Sep 17 00:00:00 2001
From: Pavel Labath <pavel at labath.sk>
Date: Mon, 20 Jan 2025 16:10:50 +0100
Subject: [PATCH 2/3] format
---
lldb/source/Commands/CommandObjectThread.cpp | 1 -
.../thread/step_until/TestStepUntil.py | 16 ++++++++++------
2 files changed, 10 insertions(+), 7 deletions(-)
diff --git a/lldb/source/Commands/CommandObjectThread.cpp b/lldb/source/Commands/CommandObjectThread.cpp
index 829abb8c5839bbc..e472359a31337ec 100644
--- a/lldb/source/Commands/CommandObjectThread.cpp
+++ b/lldb/source/Commands/CommandObjectThread.cpp
@@ -969,7 +969,6 @@ class CommandObjectThreadUntil : public CommandObjectParsed {
return;
}
-
uint32_t lowest_func_idx = UINT32_MAX;
uint32_t highest_func_idx = 0;
for (AddressRange range : sc.function->GetAddressRanges()) {
diff --git a/lldb/test/API/functionalities/thread/step_until/TestStepUntil.py b/lldb/test/API/functionalities/thread/step_until/TestStepUntil.py
index 9e2588dc61c0075..965da02ed0f9841 100644
--- a/lldb/test/API/functionalities/thread/step_until/TestStepUntil.py
+++ b/lldb/test/API/functionalities/thread/step_until/TestStepUntil.py
@@ -103,9 +103,11 @@ def test_bad_line(self):
"""Test that we get an error if attempting to step outside the current
function"""
thread = self._common_setup(None, None)
- self.expect(f"thread until {self.in_foo}",
- substrs=["Until target outside of the current function"],
- error=True)
+ self.expect(
+ f"thread until {self.in_foo}",
+ substrs=["Until target outside of the current function"],
+ error=True,
+ )
@no_debug_info_test
@skipIf(oslist=lldbplatformutil.getDarwinOSTriples() + ["windows"])
@@ -117,6 +119,8 @@ def test_bad_line_discontinuous(self):
_, _, thread, _ = lldbutil.run_to_source_breakpoint(
self, "At the start", lldb.SBFileSpec(self.main_source)
)
- self.expect(f"thread until {self.in_foo}",
- substrs=["Until target outside of the current function"],
- error=True)
+ self.expect(
+ f"thread until {self.in_foo}",
+ substrs=["Until target outside of the current function"],
+ error=True,
+ )
>From e8d4455aca3a9d3943926a64cfe309057d8d4c62 Mon Sep 17 00:00:00 2001
From: Pavel Labath <pavel at labath.sk>
Date: Mon, 20 Jan 2025 17:30:54 +0100
Subject: [PATCH 3/3] add -1 to ensure the address is within the bounds of the
function
---
lldb/source/Commands/CommandObjectThread.cpp | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/lldb/source/Commands/CommandObjectThread.cpp b/lldb/source/Commands/CommandObjectThread.cpp
index e472359a31337ec..c733210aa59c601 100644
--- a/lldb/source/Commands/CommandObjectThread.cpp
+++ b/lldb/source/Commands/CommandObjectThread.cpp
@@ -978,7 +978,7 @@ class CommandObjectThreadUntil : public CommandObjectParsed {
if (line_table->FindLineEntryByAddress(addr, unused, &idx))
lowest_func_idx = std::min(lowest_func_idx, idx);
- addr.Slide(range.GetByteSize());
+ addr.Slide(range.GetByteSize() - 1);
if (line_table->FindLineEntryByAddress(addr, unused, &idx))
highest_func_idx = std::max(highest_func_idx, idx);
}
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