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Differential D139055

[flang] Warn about more continuation lines than the standard permits
ClosedPublic

Authored by klausler on Nov 30 2022, 3:58 PM.

Details

Reviewers
clementval
sscalpone
Commits
rG8a1f12c6fbe9: [flang] Warn about more continuation lines than the standard permits
Summary

f18 doesn't have any limit on continuation lines in fixed or free form
source (other than available memory), but the standard does. Emit
a portability warning when it is exceeded.

Diff Detail

Event Timeline

klausler created this revision.Nov 30 2022, 3:58 PM
Herald added a reviewer: sscalpone. · View Herald TranscriptNov 30 2022, 3:58 PM
Herald added a project: Restricted Project. · View Herald Transcript
Herald added a subscriber: jdoerfert. · View Herald Transcript
klausler requested review of this revision.Nov 30 2022, 3:58 PM
Harbormaster completed remote builds in B200374: Diff 479090.Nov 30 2022, 4:19 PM
clementval accepted this revision.Nov 30 2022, 11:21 PM

LGTM

This revision is now accepted and ready to land.Nov 30 2022, 11:21 PM
Closed by commit rG8a1f12c6fbe9: [flang] Warn about more continuation lines than the standard permits (authored by klausler). · Explain WhyDec 2 2022, 5:07 PM
This revision was automatically updated to reflect the committed changes.
klausler added a commit: rG8a1f12c6fbe9: [flang] Warn about more continuation lines than the standard permits.

Revision Contents

PathSize
flang/
docs/
2 lines
lib/
Parser/
2 lines
13 lines
test/
Parser/
262 lines

Diff 479090

flang/docs/Extensions.md

Context not available.
* The legacy extension intrinsic functions `IZEXT` and `JZEXT` * The legacy extension intrinsic functions `IZEXT` and `JZEXT`
are supported; `ZEXT` has different behavior with various older are supported; `ZEXT` has different behavior with various older
compilers, so it is not supported. compilers, so it is not supported.
* f18 doesn't impose a limit on the number of continuation lines
allowed for a single statement.
### Extensions supported when enabled by options ### Extensions supported when enabled by options
Context not available.

flang/lib/Parser/prescan.h

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slashInCurrentStatement_ = false; slashInCurrentStatement_ = false;
preventHollerith_ = false; preventHollerith_ = false;
delimiterNesting_ = 0; delimiterNesting_ = 0;
continuationLines_ = 0;
} }
Provenance GetProvenance(const char *sourceChar) const { Provenance GetProvenance(const char *sourceChar) const {
Context not available.
Encoding encoding_{Encoding::UTF_8}; Encoding encoding_{Encoding::UTF_8};
int delimiterNesting_{0}; int delimiterNesting_{0};
int prescannerNesting_{0}; int prescannerNesting_{0};
int continuationLines_{0};
Provenance startProvenance_; Provenance startProvenance_;
const char *start_{nullptr}; // beginning of current source file content const char *start_{nullptr}; // beginning of current source file content
Context not available.

flang/lib/Parser/prescan.cpp

Context not available.
void Prescanner::Statement() { void Prescanner::Statement() {
TokenSequence tokens; TokenSequence tokens;
LineClassification line{ClassifyLine(nextLine_)}; const char *statementStart{nextLine_};
LineClassification line{ClassifyLine(statementStart)};
switch (line.kind) { switch (line.kind) {
case LineClassification::Kind::Comment: case LineClassification::Kind::Comment:
nextLine_ += line.payloadOffset; // advance to '!' or newline nextLine_ += line.payloadOffset; // advance to '!' or newline
Context not available.
while (NextToken(tokens)) { while (NextToken(tokens)) {
} }
if (continuationLines_ > 255) {
Say(GetProvenance(statementStart),
"%d continuation lines is more than the Fortran standard allows"_port_en_US,
continuationLines_);
}
Provenance newlineProvenance{GetCurrentProvenance()}; Provenance newlineProvenance{GetCurrentProvenance()};
if (std::optional<TokenSequence> preprocessed{ if (std::optional<TokenSequence> preprocessed{
Context not available.
token.CloseToken(); token.CloseToken();
SkipToNextSignificantCharacter(); SkipToNextSignificantCharacter();
if (IsDecimalDigit(*at_)) { if (IsDecimalDigit(*at_)) {
Say(GetProvenance(at_), Say(GetCurrentProvenance(),
"Label digit is not in fixed-form label field"_port_en_US); "Label digit is not in fixed-form label field"_port_en_US);
} }
} }
Context not available.
mightNeedSpace = *at_ == '\n'; mightNeedSpace = *at_ == '\n';
} }
for (; Continuation(mightNeedSpace); mightNeedSpace = false) { for (; Continuation(mightNeedSpace); mightNeedSpace = false) {
++continuationLines_;
if (MustSkipToEndOfLine()) { if (MustSkipToEndOfLine()) {
SkipToEndOfLine(); SkipToEndOfLine();
} }
Context not available.
// Recognize and skip over classic C style /*comments*/ when // Recognize and skip over classic C style /*comments*/ when
// outside a character literal. // outside a character literal.
if (features_.ShouldWarn(LanguageFeature::ClassicCComments)) { if (features_.ShouldWarn(LanguageFeature::ClassicCComments)) {
Say(GetProvenance(at_), Say(GetCurrentProvenance(),
"nonstandard usage: C-style comment"_port_en_US); "nonstandard usage: C-style comment"_port_en_US);
} }
SkipCComments(); SkipCComments();
Context not available.

flang/test/Parser/excessive-continuations.f90

  • This file was added.
! RUN: %flang_fc1 -fdebug-unparse %s 2>&1 | FileCheck %s
! CHECK: portability: 256 continuation lines is more than the Fortran standard allows
! CHECK: LOGICAL, PARAMETER :: c255 = .true._4
program test
logical, parameter :: c255 = 255 == len("&
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&")
end