[clang] [clang] Adjust TextDiagnostic style ranges for interesting source region (PR #164941)
Timm Baeder via cfe-commits
cfe-commits at lists.llvm.org
Fri Oct 31 08:13:13 PDT 2025
Timm =?utf-8?q?Bäder?= <tbaeder at redhat.com>
Message-ID:
In-Reply-To: <llvm.org/llvm/llvm-project/pull/164941 at github.com>
https://github.com/tbaederr updated https://github.com/llvm/llvm-project/pull/164941
>From a1bcecb7a604ce7c9cee9b4443e67a173328bed1 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Timm=20B=C3=A4der?= <tbaeder at redhat.com>
Date: Thu, 30 Oct 2025 14:34:00 +0100
Subject: [PATCH 1/2] [clang] Adjust TextDiagnostic style ranges for
interesting source region
---
clang/lib/Frontend/TextDiagnostic.cpp | 70 ++++++++++++++-----
...diags-interesting-source-region-colors.cpp | 30 ++++++++
2 files changed, 81 insertions(+), 19 deletions(-)
create mode 100644 clang/test/Frontend/diags-interesting-source-region-colors.cpp
diff --git a/clang/lib/Frontend/TextDiagnostic.cpp b/clang/lib/Frontend/TextDiagnostic.cpp
index aea3e72d92a84..9d2ce9a9a389e 100644
--- a/clang/lib/Frontend/TextDiagnostic.cpp
+++ b/clang/lib/Frontend/TextDiagnostic.cpp
@@ -349,14 +349,13 @@ struct SourceColumnMap {
/// When the source code line we want to print is too long for
/// the terminal, select the "interesting" region.
-static void selectInterestingSourceRegion(std::string &SourceLine,
- std::string &CaretLine,
- std::string &FixItInsertionLine,
- Columns NonGutterColumns,
- const SourceColumnMap &Map) {
- Columns CaretColumns = Columns(CaretLine.size());
- Columns FixItColumns =
- Columns(llvm::sys::locale::columnWidth(FixItInsertionLine));
+static void selectInterestingSourceRegion(
+ std::string &SourceLine, std::string &CaretLine,
+ std::string &FixItInsertionLine, Columns NonGutterColumns,
+ const SourceColumnMap &Map,
+ SmallVector<clang::TextDiagnostic::StyleRange> &Styles) {
+ Columns CaretColumns = CaretLine.size();
+ Columns FixItColumns = llvm::sys::locale::columnWidth(FixItInsertionLine);
Columns MaxColumns =
std::max({Map.columns().V, CaretColumns.V, FixItColumns.V});
// if the number of columns is less than the desired number we're done
@@ -369,13 +368,11 @@ static void selectInterestingSourceRegion(std::string &SourceLine,
// Find the slice that we need to display the full caret line
// correctly.
Columns CaretStart = 0, CaretEnd = CaretLine.size();
- for (; CaretStart != CaretEnd; CaretStart = CaretStart.next())
- if (!isWhitespace(CaretLine[CaretStart.V]))
- break;
+ while (CaretStart != CaretEnd && isWhitespace(CaretLine[CaretStart.V]))
+ CaretStart = CaretStart.next();
- for (; CaretEnd != CaretStart; CaretEnd = CaretEnd.prev())
- if (!isWhitespace(CaretLine[CaretEnd.V - 1]))
- break;
+ while (CaretEnd != CaretStart && isWhitespace(CaretLine[CaretEnd.V]))
+ CaretEnd = CaretEnd.prev();
// caret has already been inserted into CaretLine so the above whitespace
// check is guaranteed to include the caret
@@ -516,13 +513,42 @@ static void selectInterestingSourceRegion(std::string &SourceLine,
assert(FrontColumnsRemoved + ColumnsKept + BackColumnsRemoved >
NonGutterColumns);
+ // Since we've modified the SourceLine, we also need to adjust the line's
+ // highlighting information. In particular, if we've removed
+ // from the front of the line, we need to move the style ranges to the
+ // left and remove unneeded ranges.
+ Bytes BytesRemoved =
+ FrontColumnsRemoved > FrontEllipse.size()
+ ? (Map.columnToByte(FrontColumnsRemoved) - Bytes(FrontEllipse.size()))
+ : 0;
+ Bytes CodeEnd = Map.columnToByte(CaretEnd);
+ for (auto &R : Styles) {
+ if (R.End < static_cast<unsigned>(BytesRemoved.V)) {
+ R.Start = R.End = std::numeric_limits<int>::max();
+ continue;
+ }
+ // Move them left. (Note that this can wrap R.Start, but that doesn't
+ // matter).
+ R.Start -= BytesRemoved.V;
+ R.End -= BytesRemoved.V;
+
+ // Don't leak into the ellipse at the end.
+ if (R.Start < static_cast<unsigned>(CodeEnd.V) &&
+ R.End > static_cast<unsigned>(CodeEnd.V))
+ R.End = CodeEnd.V;
+
+ // Remove style ranges after the end of the snippet.
+ if (R.Start >= static_cast<unsigned>(CodeEnd.V))
+ R.Start = R.End = std::numeric_limits<int>::max();
+ }
+
// The line needs some truncation, and we'd prefer to keep the front
// if possible, so remove the back
if (BackColumnsRemoved > Columns(BackEllipse.size()))
SourceLine.replace(SourceEnd.V, std::string::npos, BackEllipse);
// If that's enough then we're done
- if (FrontColumnsRemoved + ColumnsKept <= Columns(NonGutterColumns))
+ if (FrontColumnsRemoved + ColumnsKept <= NonGutterColumns)
return;
// Otherwise remove the front as well
@@ -1391,6 +1417,12 @@ void TextDiagnostic::emitSnippetAndCaret(
OS.indent(MaxLineNoDisplayWidth + 2) << "| ";
};
+ Columns MessageLength = DiagOpts.MessageLength;
+
+ // If we don't have enough columns available, just abort now.
+ if (MessageLength != 0 && MessageLength <= Columns(MaxLineNoDisplayWidth + 4))
+ return;
+
// Prepare source highlighting information for the lines we're about to
// emit, starting from the first line.
std::unique_ptr<SmallVector<StyleRange>[]> SourceStyles =
@@ -1450,10 +1482,10 @@ void TextDiagnostic::emitSnippetAndCaret(
// If the source line is too long for our terminal, select only the
// "interesting" source region within that line.
- Columns MessageLength = DiagOpts.MessageLength;
- if (MessageLength.V != 0)
+ if (MessageLength != 0)
selectInterestingSourceRegion(SourceLine, CaretLine, FixItInsertionLine,
- MessageLength, SourceColMap);
+ MessageLength, SourceColMap,
+ SourceStyles[LineNo - Lines.first]);
// If we are in -fdiagnostics-print-source-range-info mode, we are trying
// to produce easily machine parsable output. Add a space before the
@@ -1508,7 +1540,7 @@ void TextDiagnostic::emitSnippet(StringRef SourceLine,
// Print the source line one character at a time.
bool PrintReversed = false;
std::optional<llvm::raw_ostream::Colors> CurrentColor;
- size_t I = 0;
+ size_t I = 0; // Bytes.
while (I < SourceLine.size()) {
auto [Str, WasPrintable] =
printableTextForNextCharacter(SourceLine, &I, DiagOpts.TabStop);
diff --git a/clang/test/Frontend/diags-interesting-source-region-colors.cpp b/clang/test/Frontend/diags-interesting-source-region-colors.cpp
new file mode 100644
index 0000000000000..412820a5710a9
--- /dev/null
+++ b/clang/test/Frontend/diags-interesting-source-region-colors.cpp
@@ -0,0 +1,30 @@
+// RUN: not %clang_cc1 %s -fmessage-length=40 -fcolor-diagnostics -fno-show-source-location -Wunused-value -o - 2>&1 | FileCheck %s
+
+// REQUIRES: ansi-escape-sequences
+
+int main() {
+ 1 + + if;
+ // CHECK: expected expression
+ // CHECK-NEXT: ...+ [[MAGENTA:.\[0;34m]]if[[RESET:.\[0m]];
+
+ /*😂*/1 + + if;
+ // CHECK: expected expression
+ // CHECK-NEXT: ...+ [[MAGENTA:.\[0;34m]]if[[RESET:.\[0m]];
+
+ a + 1 + 1 + 1 + 1 + 1 + 1 + 1 + 1 + 1 + 1 + 1 + 1 + 1 + 1 + 1 + 1;
+ // CHECK: use of undeclared identifier
+ // CHECK-NEXT: a + [[GREEN:.\[0;32m]]1[[RESET]] + [[GREEN]]1[[RESET]] + [[GREEN]]1[[RESET]] + [[GREEN]]1[[RESET]] + [[GREEN]]1[[RESET]] + [[GREEN]]1[[RESET]] + [[GREEN]]1[[RESET]] ...
+
+
+ /*😂😂😂*/ a + 1 + 1 + 1 + 1 + 1 + 1 + 1 + 1 + 1 + 1 + 1 + 1 + 1 + 1 + 1 + 1;
+ // CHECK: use of undeclared identifier
+ // CHECK-NEXT: [[YELLOW:.\[0;33m]]/*😂😂😂*/[[RESET]] a + [[GREEN:.\[0;32m]]1[[RESET]] + [[GREEN]]1[[RESET]] + [[GREEN]]1[[RESET]] + [[GREEN]]1[[RESET]] ...
+
+ "xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx";
+ // CHECK: [[GREEN:.\[0;32m]]"xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx"[[RESET]];
+
+ "😂xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx";
+ // CHECK: [[GREEN:.\[0;32m]]"😂xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx"[[RESET]];
+}
+
+
>From c47ddb1f0bae8989be2294a8e249f88f77659012 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Timm=20B=C3=A4der?= <tbaeder at redhat.com>
Date: Fri, 31 Oct 2025 16:12:49 +0100
Subject: [PATCH 2/2] nits
---
clang/lib/Frontend/TextDiagnostic.cpp | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/clang/lib/Frontend/TextDiagnostic.cpp b/clang/lib/Frontend/TextDiagnostic.cpp
index 9d2ce9a9a389e..9e297fa78f58a 100644
--- a/clang/lib/Frontend/TextDiagnostic.cpp
+++ b/clang/lib/Frontend/TextDiagnostic.cpp
@@ -353,7 +353,7 @@ static void selectInterestingSourceRegion(
std::string &SourceLine, std::string &CaretLine,
std::string &FixItInsertionLine, Columns NonGutterColumns,
const SourceColumnMap &Map,
- SmallVector<clang::TextDiagnostic::StyleRange> &Styles) {
+ SmallVectorImpl<clang::TextDiagnostic::StyleRange> &Styles) {
Columns CaretColumns = CaretLine.size();
Columns FixItColumns = llvm::sys::locale::columnWidth(FixItInsertionLine);
Columns MaxColumns =
@@ -522,7 +522,7 @@ static void selectInterestingSourceRegion(
? (Map.columnToByte(FrontColumnsRemoved) - Bytes(FrontEllipse.size()))
: 0;
Bytes CodeEnd = Map.columnToByte(CaretEnd);
- for (auto &R : Styles) {
+ for (TextDiagnostic::StyleRange &R : Styles) {
if (R.End < static_cast<unsigned>(BytesRemoved.V)) {
R.Start = R.End = std::numeric_limits<int>::max();
continue;
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