[Lldb-commits] [lldb] [lldb] Fix "in function" detection in "thread until" (PR #123622)
via lldb-commits
lldb-commits at lists.llvm.org
Mon Jan 20 06:32:55 PST 2025
llvmbot wrote:
<!--LLVM PR SUMMARY COMMENT-->
@llvm/pr-subscribers-lldb
Author: Pavel Labath (labath)
<details>
<summary>Changes</summary>
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.
---
Full diff: https://github.com/llvm/llvm-project/pull/123622.diff
2 Files Affected:
- (modified) lldb/source/Commands/CommandObjectThread.cpp (+30-27)
- (modified) lldb/test/API/functionalities/thread/step_until/TestStepUntil.py (+35-3)
``````````diff
diff --git a/lldb/source/Commands/CommandObjectThread.cpp b/lldb/source/Commands/CommandObjectThread.cpp
index 4e2c4c1126bc3f..829abb8c5839bb 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 1fbb404aeae58b..9e2588dc61c007 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)
``````````
</details>
https://github.com/llvm/llvm-project/pull/123622
More information about the lldb-commits
mailing list