[Lldb-commits] [lldb] [lldb] improve the heuristics for checking if a terminal supports Unicode (PR #171832)
Charles Zablit via lldb-commits
lldb-commits at lists.llvm.org
Fri Dec 12 03:36:41 PST 2025
https://github.com/charles-zablit updated https://github.com/llvm/llvm-project/pull/171832
>From e46383656970d88e4a73b5406c4a04eb7bea48a5 Mon Sep 17 00:00:00 2001
From: Charles Zablit <c_zablit at apple.com>
Date: Thu, 11 Dec 2025 14:02:09 +0000
Subject: [PATCH 1/4] [lldb] improve the heuristics for checking if a terminal
supports Unicode
---
lldb/include/lldb/Host/Terminal.h | 12 ++++++++++++
.../lldb/Host/common/DiagnosticsRendering.h | 19 ++++++++++++++++++-
.../Host/common/DiagnosticsRendering.cpp | 11 +++++------
lldb/source/Host/common/Terminal.cpp | 16 ++++++++++++++++
.../Shell/Commands/command-dwim-print.test | 8 ++++----
.../Commands/command-expr-diagnostics.test | 15 +++++++--------
lldb/test/Shell/Commands/command-options.test | 12 ++++++------
.../Host/common/DiagnosticsRenderingTest.cpp | 2 +-
8 files changed, 69 insertions(+), 26 deletions(-)
diff --git a/lldb/include/lldb/Host/Terminal.h b/lldb/include/lldb/Host/Terminal.h
index da0d05e8bd265..3d66515c18812 100644
--- a/lldb/include/lldb/Host/Terminal.h
+++ b/lldb/include/lldb/Host/Terminal.h
@@ -68,6 +68,18 @@ class Terminal {
llvm::Error SetHardwareFlowControl(bool enabled);
+ /// Returns whether or not the current terminal supports Unicode rendering.
+ ///
+ /// The value is cached after the first computation.
+ ///
+ /// On POSIX systems, we check if the LANG environment variable contains the
+ /// substring "UTF-8", case insensitive.
+ ///
+ /// On Windows, we always return true since we use the `WriteConsoleW` API
+ /// internally. Note that the default Windows codepage (437) does not support
+ /// all Unicode characters. This function does not check the codepage.
+ static bool SupportsUnicode();
+
protected:
struct Data;
diff --git a/lldb/include/lldb/Host/common/DiagnosticsRendering.h b/lldb/include/lldb/Host/common/DiagnosticsRendering.h
index dd33d671c24a5..3eea0647da37e 100644
--- a/lldb/include/lldb/Host/common/DiagnosticsRendering.h
+++ b/lldb/include/lldb/Host/common/DiagnosticsRendering.h
@@ -59,10 +59,27 @@ struct DiagnosticDetail {
StructuredData::ObjectSP Serialize(llvm::ArrayRef<DiagnosticDetail> details);
+/// Renders an array of DiagnosticDetail instances.
+///
+/// \param[in] stream
+/// The stream to render the diagnostics to.
+/// \param offset_in_command
+/// An optional offset to the column position of the diagnostic in the
+/// source.
+/// \param show_inline
+/// Whether to show the diagnostics inline.
+/// \param details
+/// The array of DiagnosticsDetail to render.
+/// \param force_ascii
+/// Whether to force ascii rendering. If false, Unicode characters will be
+/// used if the output file supports them.
+///
+/// \see lldb_private::Terminal::SupportsUnicode
void RenderDiagnosticDetails(Stream &stream,
std::optional<uint16_t> offset_in_command,
bool show_inline,
- llvm::ArrayRef<DiagnosticDetail> details);
+ llvm::ArrayRef<DiagnosticDetail> details,
+ bool force_ascii = false);
class DiagnosticError
: public llvm::ErrorInfo<DiagnosticError, CloneableECError> {
diff --git a/lldb/source/Host/common/DiagnosticsRendering.cpp b/lldb/source/Host/common/DiagnosticsRendering.cpp
index f2cd3968967fb..2c9d33a6c325c 100644
--- a/lldb/source/Host/common/DiagnosticsRendering.cpp
+++ b/lldb/source/Host/common/DiagnosticsRendering.cpp
@@ -7,6 +7,8 @@
//===----------------------------------------------------------------------===//
#include "lldb/Host/common/DiagnosticsRendering.h"
+#include "lldb/Host/Terminal.h"
+
#include <cstdint>
using namespace lldb_private;
@@ -85,7 +87,8 @@ static llvm::raw_ostream &PrintSeverity(Stream &stream,
void RenderDiagnosticDetails(Stream &stream,
std::optional<uint16_t> offset_in_command,
bool show_inline,
- llvm::ArrayRef<DiagnosticDetail> details) {
+ llvm::ArrayRef<DiagnosticDetail> details,
+ bool force_ascii) {
if (details.empty())
return;
@@ -97,12 +100,8 @@ void RenderDiagnosticDetails(Stream &stream,
return;
}
- // Since there is no other way to find this out, use the color
- // attribute as a proxy for whether the terminal supports Unicode
- // characters. In the future it might make sense to move this into
- // Host so it can be customized for a specific platform.
llvm::StringRef cursor, underline, vbar, joint, hbar, spacer;
- if (stream.AsRawOstream().colors_enabled()) {
+ if (Terminal::SupportsUnicode() && !force_ascii) {
cursor = "˄";
underline = "˜";
vbar = "│";
diff --git a/lldb/source/Host/common/Terminal.cpp b/lldb/source/Host/common/Terminal.cpp
index 436dfd8130d9b..d3647835e3937 100644
--- a/lldb/source/Host/common/Terminal.cpp
+++ b/lldb/source/Host/common/Terminal.cpp
@@ -400,6 +400,22 @@ llvm::Error Terminal::SetHardwareFlowControl(bool enabled) {
#endif // LLDB_ENABLE_TERMIOS
}
+bool Terminal::SupportsUnicode() {
+ static std::optional<bool> g_result;
+ if (g_result)
+ return g_result.value();
+#ifdef _WIN32
+ return true;
+#else
+ const char *lang_var = std::getenv("LANG");
+ if (!lang_var)
+ return false;
+ g_result =
+ llvm::StringRef(lang_var).lower().find("utf-8") != std::string::npos;
+#endif
+ return g_result.value();
+}
+
TerminalState::TerminalState(Terminal term, bool save_process_group)
: m_tty(term) {
Save(term, save_process_group);
diff --git a/lldb/test/Shell/Commands/command-dwim-print.test b/lldb/test/Shell/Commands/command-dwim-print.test
index 9153edbd21791..c30d9c7fc3f85 100644
--- a/lldb/test/Shell/Commands/command-dwim-print.test
+++ b/lldb/test/Shell/Commands/command-dwim-print.test
@@ -1,16 +1,16 @@
# RUN: echo quit | %lldb -o "dwim-print a" \
# RUN: | FileCheck %s --strict-whitespace --check-prefix=CHECK1
# (lldb) dwim-print a
-# CHECK1:{{^ \^}}
-# CHECK1: {{^ error: use of undeclared identifier 'a'}}
+# CHECK1:{{^ (\^|˄)}}
+# CHECK1: {{^ (╰─)? error: use of undeclared identifier 'a'}}
# RUN: echo quit | %lldb -o "p a" \
# RUN: | FileCheck %s --strict-whitespace --check-prefix=CHECK2
# (lldb) p a
-# CHECK2:{{^ \^}}
+# CHECK2:{{^ (\^|˄)}}
# RUN: echo quit | %lldb -o "dwim-print -- a" \
# RUN: | FileCheck %s --strict-whitespace --check-prefix=CHECK3
# (lldb) dwim-print -- a
-# CHECK3:{{^ \^}}
+# CHECK3:{{^ (\^|˄)}}
# RUN: echo quit | %lldb -o "settings set show-inline-diagnostics false" \
# RUN: -o "dwim-print a" 2>&1 | FileCheck %s --check-prefix=CHECK4
# CHECK4: error: <user expression 0>:1:1: use of undeclared identifier
diff --git a/lldb/test/Shell/Commands/command-expr-diagnostics.test b/lldb/test/Shell/Commands/command-expr-diagnostics.test
index 3c827fb4516ec..b791c8d0eece9 100644
--- a/lldb/test/Shell/Commands/command-expr-diagnostics.test
+++ b/lldb/test/Shell/Commands/command-expr-diagnostics.test
@@ -1,21 +1,20 @@
-# XFAIL: target-windows
# RUN: echo quit | %lldb -o "expression a+b" \
# RUN: | FileCheck %s --strict-whitespace --check-prefix=CHECK1
# (lldb) expression a+b
-# CHECK1:{{^ \^ \^}}
-# CHECK1: {{^ | error: use of undeclared identifier 'b'}}
-# CHECK1: {{^ error: use of undeclared identifier 'a'}}
+# CHECK1:{{^ (\^|˄) (\^|˄)}}
+# CHECK1: {{^ (\||│) (╰─)? error: use of undeclared identifier 'b'}}
+# CHECK1: {{^ (╰─)? error: use of undeclared identifier 'a'}}
# RUN: echo quit | %lldb -o "expr a" \
# RUN: | FileCheck %s --strict-whitespace --check-prefix=CHECK2
# (lldb) expr a
-# CHECK2:{{^ \^}}
+# CHECK2:{{^ (\^|˄)}}
# RUN: echo quit | %lldb -o "expr -i 0 -o 0 -- a" \
# RUN: | FileCheck %s --strict-whitespace --check-prefix=CHECK3
# (lldb) expr -i 0 -o 0 -- a
-# CHECK3:{{^ \^}}
-# CHECK3: {{^ error: use of undeclared identifier 'a'}}
+# CHECK3:{{^ (\^|˄)}}
+# CHECK3: {{^ (╰─)? error: use of undeclared identifier 'a'}}
# RUN: echo "int main(){return 0;}">%t.c
# RUN: %clang_host %t.c -o %t.exe
@@ -23,7 +22,7 @@
# RUN: "expr --top-level -- template<typename T> T FOO(T x) { return x/2;}" -o \
# RUN: "expression -- FOO(\"\")" 2>&1 | FileCheck %s --check-prefix=CHECK4
# (lldb) expression -- FOO("")
-# CHECK4:{{^ \^}}
+# CHECK4:{{^ (\^|˄)}}
# CHECK4: {{^ note: in instantiation of function template}}
# CHECK4: error: <user expression
diff --git a/lldb/test/Shell/Commands/command-options.test b/lldb/test/Shell/Commands/command-options.test
index 73aa374bde297..85cc2b881b856 100644
--- a/lldb/test/Shell/Commands/command-options.test
+++ b/lldb/test/Shell/Commands/command-options.test
@@ -1,16 +1,16 @@
# RUN: echo quit | %lldb -O "log enable -x" \
# RUN: | FileCheck %s --strict-whitespace --check-prefix=CHECK1
# (lldb) log enable -x
-# CHECK1:{{^ \^~}}
-# CHECK1: {{^ error: unknown or ambiguous option}}
+# CHECK1:{{^ (\^|˄)(~|˜)}}
+# CHECK1: {{^ (╰─)? error: unknown or ambiguous option}}
# RUN: echo quit | %lldb -O " log enable -xxxxxxx" \
# RUN: | FileCheck %s --strict-whitespace --check-prefix=CHECK2
# (lldb) log enable -xxxxxxx
-# CHECK2:{{^ \^~~~~~~~}}
-# CHECK2: {{^ error: unknown or ambiguous option}}
+# CHECK2:{{^ (\^|˄)(~|˜)+}}
+# CHECK2: {{^ (╰─)? error: unknown or ambiguous option}}
# RUN: echo quit | %lldb -O "log enable dwarf all -f dwarf.log -x" \
# RUN: | FileCheck %s --strict-whitespace --check-prefix=CHECK3
# (lldb) log enable dwarf all -f dwarf.log -x
-# CHECK3:{{^ \^~}}
-# CHECK3: {{^ error: unknown or ambiguous option}}
+# CHECK3:{{^ (\^|˄)(~|˜)}}
+# CHECK3: {{^ (╰─)? error: unknown or ambiguous option}}
diff --git a/lldb/unittests/Host/common/DiagnosticsRenderingTest.cpp b/lldb/unittests/Host/common/DiagnosticsRenderingTest.cpp
index 851b478def32e..896ce1995fe1c 100644
--- a/lldb/unittests/Host/common/DiagnosticsRenderingTest.cpp
+++ b/lldb/unittests/Host/common/DiagnosticsRenderingTest.cpp
@@ -10,7 +10,7 @@ class ErrorDisplayTest : public ::testing::Test {};
std::string Render(std::vector<DiagnosticDetail> details) {
StreamString stream;
- RenderDiagnosticDetails(stream, 0, true, details);
+ RenderDiagnosticDetails(stream, 0, true, details, /*force_ascii=*/true);
return stream.GetData();
}
} // namespace
>From 71fcf5d2b03854898a0b2f14d365d162cd4130bc Mon Sep 17 00:00:00 2001
From: Charles Zablit <c_zablit at apple.com>
Date: Thu, 11 Dec 2025 14:36:12 +0000
Subject: [PATCH 2/4] fixup! [lldb] improve the heuristics for checking if a
terminal supports Unicode
---
lldb/test/Shell/Commands/command-dwim-print.test | 2 +-
lldb/test/Shell/Commands/command-expr-diagnostics.test | 6 +++---
lldb/test/Shell/Commands/command-options.test | 6 +++---
3 files changed, 7 insertions(+), 7 deletions(-)
diff --git a/lldb/test/Shell/Commands/command-dwim-print.test b/lldb/test/Shell/Commands/command-dwim-print.test
index c30d9c7fc3f85..8c2697d8ebf8c 100644
--- a/lldb/test/Shell/Commands/command-dwim-print.test
+++ b/lldb/test/Shell/Commands/command-dwim-print.test
@@ -2,7 +2,7 @@
# RUN: | FileCheck %s --strict-whitespace --check-prefix=CHECK1
# (lldb) dwim-print a
# CHECK1:{{^ (\^|˄)}}
-# CHECK1: {{^ (╰─)? error: use of undeclared identifier 'a'}}
+# CHECK1: {{^ (╰─ )?error: use of undeclared identifier 'a'}}
# RUN: echo quit | %lldb -o "p a" \
# RUN: | FileCheck %s --strict-whitespace --check-prefix=CHECK2
# (lldb) p a
diff --git a/lldb/test/Shell/Commands/command-expr-diagnostics.test b/lldb/test/Shell/Commands/command-expr-diagnostics.test
index b791c8d0eece9..4888f344c93df 100644
--- a/lldb/test/Shell/Commands/command-expr-diagnostics.test
+++ b/lldb/test/Shell/Commands/command-expr-diagnostics.test
@@ -2,8 +2,8 @@
# RUN: | FileCheck %s --strict-whitespace --check-prefix=CHECK1
# (lldb) expression a+b
# CHECK1:{{^ (\^|˄) (\^|˄)}}
-# CHECK1: {{^ (\||│) (╰─)? error: use of undeclared identifier 'b'}}
-# CHECK1: {{^ (╰─)? error: use of undeclared identifier 'a'}}
+# CHECK1: {{^ (\||│) (╰─ )?error: use of undeclared identifier 'b'}}
+# CHECK1: {{^ (╰─ )?error: use of undeclared identifier 'a'}}
# RUN: echo quit | %lldb -o "expr a" \
# RUN: | FileCheck %s --strict-whitespace --check-prefix=CHECK2
@@ -14,7 +14,7 @@
# RUN: | FileCheck %s --strict-whitespace --check-prefix=CHECK3
# (lldb) expr -i 0 -o 0 -- a
# CHECK3:{{^ (\^|˄)}}
-# CHECK3: {{^ (╰─)? error: use of undeclared identifier 'a'}}
+# CHECK3: {{^ (╰─ )?error: use of undeclared identifier 'a'}}
# RUN: echo "int main(){return 0;}">%t.c
# RUN: %clang_host %t.c -o %t.exe
diff --git a/lldb/test/Shell/Commands/command-options.test b/lldb/test/Shell/Commands/command-options.test
index 85cc2b881b856..f75c0993ed78e 100644
--- a/lldb/test/Shell/Commands/command-options.test
+++ b/lldb/test/Shell/Commands/command-options.test
@@ -2,15 +2,15 @@
# RUN: | FileCheck %s --strict-whitespace --check-prefix=CHECK1
# (lldb) log enable -x
# CHECK1:{{^ (\^|˄)(~|˜)}}
-# CHECK1: {{^ (╰─)? error: unknown or ambiguous option}}
+# CHECK1: {{^ (╰─ )?error: unknown or ambiguous option}}
# RUN: echo quit | %lldb -O " log enable -xxxxxxx" \
# RUN: | FileCheck %s --strict-whitespace --check-prefix=CHECK2
# (lldb) log enable -xxxxxxx
# CHECK2:{{^ (\^|˄)(~|˜)+}}
-# CHECK2: {{^ (╰─)? error: unknown or ambiguous option}}
+# CHECK2: {{^ (╰─ )?error: unknown or ambiguous option}}
# RUN: echo quit | %lldb -O "log enable dwarf all -f dwarf.log -x" \
# RUN: | FileCheck %s --strict-whitespace --check-prefix=CHECK3
# (lldb) log enable dwarf all -f dwarf.log -x
# CHECK3:{{^ (\^|˄)(~|˜)}}
-# CHECK3: {{^ (╰─)? error: unknown or ambiguous option}}
+# CHECK3: {{^ (╰─ )?error: unknown or ambiguous option}}
>From 502409a6d2143ce48e0b40fcc96a4542ef801a28 Mon Sep 17 00:00:00 2001
From: Charles Zablit <c_zablit at apple.com>
Date: Thu, 11 Dec 2025 14:38:34 +0000
Subject: [PATCH 3/4] fixup! [lldb] improve the heuristics for checking if a
terminal supports Unicode
---
lldb/test/Shell/Commands/command-expr-diagnostics.test | 1 +
1 file changed, 1 insertion(+)
diff --git a/lldb/test/Shell/Commands/command-expr-diagnostics.test b/lldb/test/Shell/Commands/command-expr-diagnostics.test
index 4888f344c93df..0cb3cd381f3e2 100644
--- a/lldb/test/Shell/Commands/command-expr-diagnostics.test
+++ b/lldb/test/Shell/Commands/command-expr-diagnostics.test
@@ -1,3 +1,4 @@
+# XFAIL: target-windows
# RUN: echo quit | %lldb -o "expression a+b" \
# RUN: | FileCheck %s --strict-whitespace --check-prefix=CHECK1
# (lldb) expression a+b
>From fcb3652b047e846dff293b3d693c1dcf7fd679bd Mon Sep 17 00:00:00 2001
From: Charles Zablit <c_zablit at apple.com>
Date: Fri, 12 Dec 2025 11:36:28 +0000
Subject: [PATCH 4/4] fixup! [lldb] improve the heuristics for checking if a
terminal supports Unicode
---
lldb/source/Host/common/Terminal.cpp | 9 +++++----
1 file changed, 5 insertions(+), 4 deletions(-)
diff --git a/lldb/source/Host/common/Terminal.cpp b/lldb/source/Host/common/Terminal.cpp
index d3647835e3937..b6d09425e956e 100644
--- a/lldb/source/Host/common/Terminal.cpp
+++ b/lldb/source/Host/common/Terminal.cpp
@@ -401,19 +401,20 @@ llvm::Error Terminal::SetHardwareFlowControl(bool enabled) {
}
bool Terminal::SupportsUnicode() {
- static std::optional<bool> g_result;
- if (g_result)
- return g_result.value();
#ifdef _WIN32
return true;
#else
+ static std::optional<bool> g_result;
+ if (g_result)
+ return g_result.value();
+
const char *lang_var = std::getenv("LANG");
if (!lang_var)
return false;
g_result =
llvm::StringRef(lang_var).lower().find("utf-8") != std::string::npos;
-#endif
return g_result.value();
+#endif
}
TerminalState::TerminalState(Terminal term, bool save_process_group)
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