[flang-commits] [flang] [flang][preprocessor] Fixed-form continuation across preprocessing di… (PR #95332)
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Wed Jun 12 16:45:46 PDT 2024
llvmbot wrote:
<!--LLVM PR SUMMARY COMMENT-->
@llvm/pr-subscribers-flang-parser
Author: Peter Klausler (klausler)
<details>
<summary>Changes</summary>
…rective
Implement fixed-form line continuation when the continuation line is the result of text produced by an #include or other preprocessing directive. This accommodates the somewhat common practice of putting dummy or actual arguments into a header file and #including it into several code sites.
Fixes https://github.com/llvm/llvm-project/issues/78928.
---
Full diff: https://github.com/llvm/llvm-project/pull/95332.diff
8 Files Affected:
- (modified) flang/include/flang/Parser/provenance.h (+5)
- (modified) flang/include/flang/Parser/token-sequence.h (+1)
- (modified) flang/lib/Parser/prescan.cpp (+17-3)
- (modified) flang/lib/Parser/prescan.h (+2)
- (modified) flang/lib/Parser/provenance.cpp (+10)
- (modified) flang/lib/Parser/token-sequence.cpp (+8-4)
- (added) flang/test/Preprocessing/ff-args.h (+1)
- (added) flang/test/Preprocessing/ff-include-args.F (+14)
``````````diff
diff --git a/flang/include/flang/Parser/provenance.h b/flang/include/flang/Parser/provenance.h
index 73d500f32831b..42c5b3de2cbe2 100644
--- a/flang/include/flang/Parser/provenance.h
+++ b/flang/include/flang/Parser/provenance.h
@@ -257,6 +257,10 @@ class CookedSource {
provenanceMap_.Put(pm);
}
+ void MarkPossibleFixedFormContinuation() {
+ possibleFixedFormContinuations_.push_back(BufferedBytes());
+ }
+
std::size_t BufferedBytes() const;
void Marshal(AllCookedSources &); // marshals text into one contiguous block
void CompileProvenanceRangeToOffsetMappings(AllSources &);
@@ -269,6 +273,7 @@ class CookedSource {
std::string data_; // all of it, prescanned and preprocessed
OffsetToProvenanceMappings provenanceMap_;
ProvenanceRangeToOffsetMappings invertedMap_;
+ std::list<std::size_t> possibleFixedFormContinuations_;
};
class AllCookedSources {
diff --git a/flang/include/flang/Parser/token-sequence.h b/flang/include/flang/Parser/token-sequence.h
index ee5f71edd03c8..1f82a3c1a203a 100644
--- a/flang/include/flang/Parser/token-sequence.h
+++ b/flang/include/flang/Parser/token-sequence.h
@@ -125,6 +125,7 @@ class TokenSequence {
TokenSequence &ClipComment(const Prescanner &, bool skipFirst = false);
const TokenSequence &CheckBadFortranCharacters(
Messages &, const Prescanner &, bool allowAmpersand) const;
+ bool BadlyNestedParentheses() const;
const TokenSequence &CheckBadParentheses(Messages &) const;
void Emit(CookedSource &) const;
llvm::raw_ostream &Dump(llvm::raw_ostream &) const;
diff --git a/flang/lib/Parser/prescan.cpp b/flang/lib/Parser/prescan.cpp
index e4801c36505b4..8efcd617cf0f9 100644
--- a/flang/lib/Parser/prescan.cpp
+++ b/flang/lib/Parser/prescan.cpp
@@ -295,8 +295,13 @@ void Prescanner::CheckAndEmitLine(
// Applications play shenanigans with line continuation before and
// after #include'd subprogram argument lists.
if (!isNestedInIncludeDirective_ && !omitNewline_ &&
- !afterIncludeDirective_) {
- tokens.CheckBadParentheses(messages_);
+ !afterIncludeDirective_ && tokens.BadlyNestedParentheses()) {
+ if (inFixedForm_ && nextLine_ < limit_ &&
+ IsPreprocessorDirectiveLine(nextLine_)) {
+ // don't complain
+ } else {
+ tokens.CheckBadParentheses(messages_);
+ }
}
tokens.Emit(cooked_);
if (omitNewline_) {
@@ -350,7 +355,16 @@ void Prescanner::LabelField(TokenSequence &token) {
++column_;
}
if (badColumn && !preprocessor_.IsNameDefined(token.CurrentOpenToken())) {
- if (features_.ShouldWarn(common::UsageWarning::Scanning)) {
+ if (prescannerNesting_ > 0 && *badColumn == 6 &&
+ cooked_.BufferedBytes() == firstCookedCharacterOffset_) {
+ // This is the first source line in #included text or conditional
+ // code under #if.
+ // If it turns out that the preprocessed text begins with a
+ // fixed form continuation line, the newline at the end
+ // of the latest source line beforehand will be deleted in
+ // CookedSource::Marshal().
+ cooked_.MarkPossibleFixedFormContinuation();
+ } else if (features_.ShouldWarn(common::UsageWarning::Scanning)) {
Say(GetProvenance(start + *badColumn - 1),
*badColumn == 6
? "Statement should not begin with a continuation line"_warn_en_US
diff --git a/flang/lib/Parser/prescan.h b/flang/lib/Parser/prescan.h
index cf64bdb02a9b7..b6f6d2ca439ee 100644
--- a/flang/lib/Parser/prescan.h
+++ b/flang/lib/Parser/prescan.h
@@ -247,6 +247,8 @@ class Prescanner {
bool omitNewline_{false};
bool skipLeadingAmpersand_{false};
+ const std::size_t firstCookedCharacterOffset_{cooked_.BufferedBytes()};
+
const Provenance spaceProvenance_{
allSources_.CompilerInsertionProvenance(' ')};
const Provenance backslashProvenance_{
diff --git a/flang/lib/Parser/provenance.cpp b/flang/lib/Parser/provenance.cpp
index 55ef67fd6288d..6e2e7326e2167 100644
--- a/flang/lib/Parser/provenance.cpp
+++ b/flang/lib/Parser/provenance.cpp
@@ -513,6 +513,16 @@ void CookedSource::Marshal(AllCookedSources &allCookedSources) {
"(after end of source)"));
data_ = buffer_.Marshal();
buffer_.clear();
+ for (std::size_t ffStart : possibleFixedFormContinuations_) {
+ if (ffStart > 0 && ffStart + 1 < data_.size() &&
+ data_[ffStart - 1] == '\n' && data_[ffStart] == ' ') {
+ // This fixed form include line is the first source line in an
+ // #include file (or after an empty one). Connect it with the previous
+ // source line by deleting its terminal newline.
+ data_[ffStart - 1] = ' ';
+ }
+ }
+ possibleFixedFormContinuations_.clear();
allCookedSources.Register(*this);
}
diff --git a/flang/lib/Parser/token-sequence.cpp b/flang/lib/Parser/token-sequence.cpp
index 40560bbacb54f..133e60ba4f009 100644
--- a/flang/lib/Parser/token-sequence.cpp
+++ b/flang/lib/Parser/token-sequence.cpp
@@ -378,9 +378,7 @@ const TokenSequence &TokenSequence::CheckBadFortranCharacters(
return *this;
}
-const TokenSequence &TokenSequence::CheckBadParentheses(
- Messages &messages) const {
- // First, a quick pass with no allocation for the common case
+bool TokenSequence::BadlyNestedParentheses() const {
int nesting{0};
std::size_t tokens{SizeInTokens()};
for (std::size_t j{0}; j < tokens; ++j) {
@@ -394,8 +392,14 @@ const TokenSequence &TokenSequence::CheckBadParentheses(
}
}
}
- if (nesting != 0) {
+ return nesting != 0;
+}
+
+const TokenSequence &TokenSequence::CheckBadParentheses(
+ Messages &messages) const {
+ if (BadlyNestedParentheses()) {
// There's an error; diagnose it
+ std::size_t tokens{SizeInTokens()};
std::vector<std::size_t> stack;
for (std::size_t j{0}; j < tokens; ++j) {
CharBlock token{TokenAt(j)};
diff --git a/flang/test/Preprocessing/ff-args.h b/flang/test/Preprocessing/ff-args.h
new file mode 100644
index 0000000000000..99562784006c9
--- /dev/null
+++ b/flang/test/Preprocessing/ff-args.h
@@ -0,0 +1 @@
+ +3.14159)
\ No newline at end of file
diff --git a/flang/test/Preprocessing/ff-include-args.F b/flang/test/Preprocessing/ff-include-args.F
new file mode 100644
index 0000000000000..81e4102598c2f
--- /dev/null
+++ b/flang/test/Preprocessing/ff-include-args.F
@@ -0,0 +1,14 @@
+! RUN: %flang -E %s 2>&1 | FileCheck %s
+! CHECK: call foo ( 3.14159)
+! CHECK: subroutine foo(test)
+ call foo (
+#include "ff-args.h"
+ end
+#define TEST
+ subroutine foo(
+#ifdef TEST
+ +test)
+#else
+ +)
+#endif
+ end
``````````
</details>
https://github.com/llvm/llvm-project/pull/95332
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