[llvm] [FileCheck] Improve printing variables with escapes (PR #145865)
Mészáros Gergely via llvm-commits
llvm-commits at lists.llvm.org
Thu Jun 26 03:14:33 PDT 2025
https://github.com/Maetveis created https://github.com/llvm/llvm-project/pull/145865
Firstly fix FileCheck printing string variables
double-escaped (first regex, then C-style).
This is confusing because it is not clear if the printed
value is the literal value or exactly how it is escaped, without
looking at FileCheck's source code.
Secondly, only escape when doing so makes it easier to read the value
(when the string contains tabs, newlines or non-printable characters).
When the variable value is escaped, make a note of it in the output too,
in order to avoid confusion.
The common case that is motivating this change is variables that contain
windows style paths with backslashes. These were printed as
`"C:\\\\Program Files\\\\MyApp\\\\file.txt"`.
Now prefer to print them as `"C:\Program Files\MyApp\file.txt"`.
Printing the value literally also makes it easier to search for
variables in the output, since the user can just copy-paste it.
>From 753c46310d748fafd3de60b7e8f572ce918cf95b Mon Sep 17 00:00:00 2001
From: Gergely Meszaros <gergely.meszaros at intel.com>
Date: Thu, 26 Jun 2025 02:50:47 -0700
Subject: [PATCH 1/2] [FileCheck][NFC] Pre-commit test for printing escaped
variables
---
llvm/test/FileCheck/var-escape.txt | 17 +++++++++++++++++
1 file changed, 17 insertions(+)
create mode 100644 llvm/test/FileCheck/var-escape.txt
diff --git a/llvm/test/FileCheck/var-escape.txt b/llvm/test/FileCheck/var-escape.txt
new file mode 100644
index 0000000000000..32760bc0c9280
--- /dev/null
+++ b/llvm/test/FileCheck/var-escape.txt
@@ -0,0 +1,17 @@
+; RUN: echo -e "WINPATH=A:\windows\style\path" > %t
+; RUN: echo -e "NOT_ESCAPED=shouldn't be escaped [a-Z]\+$" >> %t
+; RUN: echo -e 'ESCAPED=\\ needs\to "be" escaped\000' >> %t
+
+VARS: WINPATH=[[WINPATH:.*]]
+VARS: NOT_ESCAPED=[[NOT_ESCAPED:.*]]
+VARS-NEXT: ESCAPED=[[ESCAPED:.*]]
+; Trigger a failed match, to show variables values
+VARS-NEXT: [[WINPATH]] [[NOT_ESCAPED]] [[ESCAPED]]
+
+; RUN: %ProtectFileCheckOutput not FileCheck \
+; RUN: -dump-input=never --strict-whitespace --check-prefix=VARS --input-file=%t %s 2>&1 \
+; RUN: | FileCheck %s
+
+CHECK: with "WINPATH" equal to "A:\\\\windows\\\\style\\\\path"
+CHECK: with "NOT_ESCAPED" equal to "shouldn't be escaped \\[a-Z\\]\\\\\\+\\$"
+CHECK: with "ESCAPED" equal to "\\\\ needs\to \"be\" escaped\\\000"
>From 731f6c6198f857c713d120f83407708b6d68993a Mon Sep 17 00:00:00 2001
From: Gergely Meszaros <gergely.meszaros at intel.com>
Date: Thu, 26 Jun 2025 02:54:21 -0700
Subject: [PATCH 2/2] [FileCheck] Improve printing variables with escapes
Firstly fix FileCheck printing string variables
double-escaped (first regex, then C-style).
This is confusing because it is not clear if the printed
value is the literal value or exactly how it is escaped, without
looking at FileCheck's source code.
Secondly, only escape when doing so makes it easier to read the value
(when the string contains tabs, newlines or non-printable characters).
When the variable value is escaped, make a note of it in the output too,
in order to avoid confusion.
The common case that is motivating this change is variables that contain
windows style paths with backslashes. These were printed as
`"C:\\\\Program Files\\\\MyApp\\\\file.txt"`.
Now prefer to print them as `"C:\Program Files\MyApp\file.txt"`.
Printing the value literally also makes it easier to search for
variables in the output, since the user can just copy-paste it.
---
llvm/lib/FileCheck/FileCheck.cpp | 53 ++++++++++++++++++++++++++----
llvm/lib/FileCheck/FileCheckImpl.h | 21 +++++++++---
llvm/test/FileCheck/var-escape.txt | 6 ++--
3 files changed, 67 insertions(+), 13 deletions(-)
diff --git a/llvm/lib/FileCheck/FileCheck.cpp b/llvm/lib/FileCheck/FileCheck.cpp
index bcca499322aee..5ddb7420820dc 100644
--- a/llvm/lib/FileCheck/FileCheck.cpp
+++ b/llvm/lib/FileCheck/FileCheck.cpp
@@ -264,7 +264,7 @@ BinaryOperation::getImplicitFormat(const SourceMgr &SM) const {
: *RightFormat;
}
-Expected<std::string> NumericSubstitution::getResult() const {
+Expected<std::string> NumericSubstitution::getResultRegex() const {
assert(ExpressionPointer->getAST() != nullptr &&
"Substituting empty expression");
Expected<APInt> EvaluatedValue = ExpressionPointer->getAST()->eval();
@@ -274,7 +274,17 @@ Expected<std::string> NumericSubstitution::getResult() const {
return Format.getMatchingString(*EvaluatedValue);
}
-Expected<std::string> StringSubstitution::getResult() const {
+Expected<std::string> NumericSubstitution::getResultForDiagnostics() const {
+ // The "regex" returned by getResultRegex() is just a numeric value
+ // like '42', '0x2A', '-17', 'DEADBEEF' etc. This is already suitable for use in diagnostics.
+ Expected<std::string> Literal = getResultRegex();
+ if (!Literal)
+ return Literal;
+
+ return "\"" + std::move(*Literal) + "\"";
+}
+
+Expected<std::string> StringSubstitution::getResultRegex() const {
// Look up the value and escape it so that we can put it into the regex.
Expected<StringRef> VarVal = Context->getPatternVarValue(FromStr);
if (!VarVal)
@@ -282,6 +292,37 @@ Expected<std::string> StringSubstitution::getResult() const {
return Regex::escape(*VarVal);
}
+Expected<std::string> StringSubstitution::getResultForDiagnostics() const {
+ Expected<StringRef> VarVal = Context->getPatternVarValue(FromStr);
+ if (!VarVal)
+ return VarVal.takeError();
+
+ std::string Result;
+ Result.reserve(VarVal->size() + 2);
+ raw_string_ostream OS(Result);
+
+ OS << '"';
+ // Escape the string if it contains any characters that
+ // make it hard to read, such as tabs, newlines, quotes, and non-printable characters.
+ // Note that we do not include backslashes in this set, because they are
+ // common in Windows paths and escaping them would make the output
+ // harder to read.
+ // However, when we do escape, backslashes are escaped as well,
+ // otherwise the output would be ambiguous.
+ const bool NeedsEscaping = llvm::any_of(*VarVal, [](char C) {
+ return C == '\t' || C == '\n' || C == '"' || !isPrint(C);
+ });
+ if (NeedsEscaping)
+ OS.write_escaped(*VarVal);
+ else
+ OS << *VarVal;
+ OS << '"';
+ if (NeedsEscaping)
+ OS << " (escaped value)";
+
+ return Result;
+}
+
bool Pattern::isValidVarNameStart(char C) { return C == '_' || isAlpha(C); }
Expected<Pattern::VariableProperties>
@@ -1106,7 +1147,7 @@ Pattern::MatchResult Pattern::match(StringRef Buffer,
Error Errs = Error::success();
for (const auto &Substitution : Substitutions) {
// Substitute and check for failure (e.g. use of undefined variable).
- Expected<std::string> Value = Substitution->getResult();
+ Expected<std::string> Value = Substitution->getResultRegex();
if (!Value) {
// Convert to an ErrorDiagnostic to get location information. This is
// done here rather than printMatch/printNoMatch since now we know which
@@ -1210,7 +1251,7 @@ void Pattern::printSubstitutions(const SourceMgr &SM, StringRef Buffer,
SmallString<256> Msg;
raw_svector_ostream OS(Msg);
- Expected<std::string> MatchedValue = Substitution->getResult();
+ Expected<std::string> MatchedValue = Substitution->getResultForDiagnostics();
// Substitution failures are handled in printNoMatch().
if (!MatchedValue) {
consumeError(MatchedValue.takeError());
@@ -1218,8 +1259,8 @@ void Pattern::printSubstitutions(const SourceMgr &SM, StringRef Buffer,
}
OS << "with \"";
- OS.write_escaped(Substitution->getFromString()) << "\" equal to \"";
- OS.write_escaped(*MatchedValue) << "\"";
+ OS.write_escaped(Substitution->getFromString()) << "\" equal to ";
+ OS << *MatchedValue;
// We report only the start of the match/search range to suggest we are
// reporting the substitutions as set at the start of the match/search.
diff --git a/llvm/lib/FileCheck/FileCheckImpl.h b/llvm/lib/FileCheck/FileCheckImpl.h
index b3cd2af5d57e3..176668a3e5154 100644
--- a/llvm/lib/FileCheck/FileCheckImpl.h
+++ b/llvm/lib/FileCheck/FileCheckImpl.h
@@ -366,9 +366,14 @@ class Substitution {
/// \returns the index where the substitution is to be performed in RegExStr.
size_t getIndex() const { return InsertIdx; }
- /// \returns a string containing the result of the substitution represented
+ /// \returns a regular expression string that matches the result of the substitution represented
/// by this class instance or an error if substitution failed.
- virtual Expected<std::string> getResult() const = 0;
+ virtual Expected<std::string> getResultRegex() const = 0;
+
+ /// \returns a string containing the result of the substitution represented
+ /// by this class instance in a form suitable for diagnostics, or an error if
+ /// substitution failed.
+ virtual Expected<std::string> getResultForDiagnostics() const = 0;
};
class StringSubstitution : public Substitution {
@@ -379,7 +384,11 @@ class StringSubstitution : public Substitution {
/// \returns the text that the string variable in this substitution matched
/// when defined, or an error if the variable is undefined.
- Expected<std::string> getResult() const override;
+ Expected<std::string> getResultRegex() const override;
+
+ /// \returns the text that the string variable in this substitution matched
+ /// when defined, in a form suitable for diagnostics, or an error if the variable is undefined.
+ Expected<std::string> getResultForDiagnostics() const override;
};
class NumericSubstitution : public Substitution {
@@ -397,7 +406,11 @@ class NumericSubstitution : public Substitution {
/// \returns a string containing the result of evaluating the expression in
/// this substitution, or an error if evaluation failed.
- Expected<std::string> getResult() const override;
+ Expected<std::string> getResultRegex() const override;
+
+ /// \returns a string containing the result of evaluating the expression in
+ /// this substitution, in a form suitable for diagnostics, or an error if evaluation failed.
+ Expected<std::string> getResultForDiagnostics() const override;
};
//===----------------------------------------------------------------------===//
diff --git a/llvm/test/FileCheck/var-escape.txt b/llvm/test/FileCheck/var-escape.txt
index 32760bc0c9280..b18caf701ceac 100644
--- a/llvm/test/FileCheck/var-escape.txt
+++ b/llvm/test/FileCheck/var-escape.txt
@@ -12,6 +12,6 @@ VARS-NEXT: [[WINPATH]] [[NOT_ESCAPED]] [[ESCAPED]]
; RUN: -dump-input=never --strict-whitespace --check-prefix=VARS --input-file=%t %s 2>&1 \
; RUN: | FileCheck %s
-CHECK: with "WINPATH" equal to "A:\\\\windows\\\\style\\\\path"
-CHECK: with "NOT_ESCAPED" equal to "shouldn't be escaped \\[a-Z\\]\\\\\\+\\$"
-CHECK: with "ESCAPED" equal to "\\\\ needs\to \"be\" escaped\\\000"
+CHECK: with "WINPATH" equal to "A:\windows\style\path"
+CHECK: with "NOT_ESCAPED" equal to "shouldn't be escaped [a-Z]\+$"
+CHECK: with "ESCAPED" equal to "\\ needs\to \"be\" escaped\000" (escaped value)
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