[Lldb-commits] [lldb] r335448 - Revert "[FileSpec] Always normalize"
Jonas Devlieghere via lldb-commits
lldb-commits at lists.llvm.org
Mon Jun 25 03:11:53 PDT 2018
Author: jdevlieghere
Date: Mon Jun 25 03:11:53 2018
New Revision: 335448
URL: http://llvm.org/viewvc/llvm-project?rev=335448&view=rev
Log:
Revert "[FileSpec] Always normalize"
This reverts r335432 because remove_dots() is expensive and measuring
its impact showed an observable performance regression
(https://reviews.llvm.org/D45977#1078510).
Modified:
lldb/trunk/source/Utility/FileSpec.cpp
Modified: lldb/trunk/source/Utility/FileSpec.cpp
URL: http://llvm.org/viewvc/llvm-project/lldb/trunk/source/Utility/FileSpec.cpp?rev=335448&r1=335447&r2=335448&view=diff
==============================================================================
--- lldb/trunk/source/Utility/FileSpec.cpp (original)
+++ lldb/trunk/source/Utility/FileSpec.cpp Mon Jun 25 03:11:53 2018
@@ -119,6 +119,100 @@ FileSpec::FileSpec(const FileSpec *rhs)
//------------------------------------------------------------------
FileSpec::~FileSpec() {}
+namespace {
+//------------------------------------------------------------------
+/// Safely get a character at the specified index.
+///
+/// @param[in] path
+/// A full, partial, or relative path to a file.
+///
+/// @param[in] i
+/// An index into path which may or may not be valid.
+///
+/// @return
+/// The character at index \a i if the index is valid, or 0 if
+/// the index is not valid.
+//------------------------------------------------------------------
+inline char safeCharAtIndex(const llvm::StringRef &path, size_t i) {
+ if (i < path.size())
+ return path[i];
+ return 0;
+}
+
+//------------------------------------------------------------------
+/// Check if a path needs to be normalized.
+///
+/// Check if a path needs to be normalized. We currently consider a
+/// path to need normalization if any of the following are true
+/// - path contains "/./"
+/// - path contains "/../"
+/// - path contains "//"
+/// - path ends with "/"
+/// Paths that start with "./" or with "../" are not considered to
+/// need normalization since we aren't trying to resolve the path,
+/// we are just trying to remove redundant things from the path.
+///
+/// @param[in] path
+/// A full, partial, or relative path to a file.
+///
+/// @return
+/// Returns \b true if the path needs to be normalized.
+//------------------------------------------------------------------
+bool needsNormalization(const llvm::StringRef &path) {
+ if (path.empty())
+ return false;
+ // We strip off leading "." values so these paths need to be normalized
+ if (path[0] == '.')
+ return true;
+ for (auto i = path.find_first_of("\\/"); i != llvm::StringRef::npos;
+ i = path.find_first_of("\\/", i + 1)) {
+ const auto next = safeCharAtIndex(path, i+1);
+ switch (next) {
+ case 0:
+ // path separator char at the end of the string which should be
+ // stripped unless it is the one and only character
+ return i > 0;
+ case '/':
+ case '\\':
+ // two path separator chars in the middle of a path needs to be
+ // normalized
+ if (i > 0)
+ return true;
+ ++i;
+ break;
+
+ case '.': {
+ const auto next_next = safeCharAtIndex(path, i+2);
+ switch (next_next) {
+ default: break;
+ case 0: return true; // ends with "/."
+ case '/':
+ case '\\':
+ return true; // contains "/./"
+ case '.': {
+ const auto next_next_next = safeCharAtIndex(path, i+3);
+ switch (next_next_next) {
+ default: break;
+ case 0: return true; // ends with "/.."
+ case '/':
+ case '\\':
+ return true; // contains "/../"
+ }
+ break;
+ }
+ }
+ }
+ break;
+
+ default:
+ break;
+ }
+ }
+ return false;
+}
+
+
+}
//------------------------------------------------------------------
// Assignment operator.
//------------------------------------------------------------------
@@ -158,7 +252,8 @@ void FileSpec::SetFile(llvm::StringRef p
}
// Normalize the path by removing ".", ".." and other redundant components.
- llvm::sys::path::remove_dots(resolved, true, m_style);
+ if (needsNormalization(resolved))
+ llvm::sys::path::remove_dots(resolved, true, m_style);
// Normalize back slashes to forward slashes
if (m_style == Style::windows)
@@ -175,10 +270,10 @@ void FileSpec::SetFile(llvm::StringRef p
// Split path into filename and directory. We rely on the underlying char
// pointer to be nullptr when the components are empty.
llvm::StringRef filename = llvm::sys::path::filename(resolved, m_style);
- if (!filename.empty())
+ if(!filename.empty())
m_filename.SetString(filename);
llvm::StringRef directory = llvm::sys::path::parent_path(resolved, m_style);
- if (!directory.empty())
+ if(!directory.empty())
m_directory.SetString(directory);
}
@@ -329,8 +424,9 @@ bool FileSpec::Equal(const FileSpec &a,
// case sensitivity of equality test
const bool case_sensitive = a.IsCaseSensitive() || b.IsCaseSensitive();
- const bool filenames_equal =
- ConstString::Equals(a.m_filename, b.m_filename, case_sensitive);
+ const bool filenames_equal = ConstString::Equals(a.m_filename,
+ b.m_filename,
+ case_sensitive);
if (!filenames_equal)
return false;
@@ -616,7 +712,9 @@ bool FileSpec::IsSourceImplementationFil
return g_source_file_regex.Execute(extension.GetStringRef());
}
-bool FileSpec::IsRelative() const { return !IsAbsolute(); }
+bool FileSpec::IsRelative() const {
+ return !IsAbsolute();
+}
bool FileSpec::IsAbsolute() const {
llvm::SmallString<64> current_path;
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