[flang-commits] [flang] 2849e11 - [flang] Handle @PROCESS directive

[Kelvin Li via flang-commits]

Author: Kelvin Li
Date: 2023-05-21T22:37:28-04:00
New Revision: 2849e11907c6dfea40ab41773654f202817934e5

URL: https://github.com/llvm/llvm-project/commit/2849e11907c6dfea40ab41773654f202817934e5
DIFF: https://github.com/llvm/llvm-project/commit/2849e11907c6dfea40ab41773654f202817934e5.diff

LOG: [flang] Handle @PROCESS directive

Treat lines that start with @process as a comment line. The directive
is accepted and ignored.

Differential Revision: https://reviews.llvm.org/D150883

Added: 
    flang/test/Parser/at-process.f
    flang/test/Parser/at-process.f90

Modified: 
    flang/docs/Extensions.md
    flang/lib/Parser/prescan.cpp

Removed: 
    


################################################################################
diff  --git a/flang/docs/Extensions.md b/flang/docs/Extensions.md
index a91596765a594..a422b2c7eb0a4 100644
--- a/flang/docs/Extensions.md
+++ b/flang/docs/Extensions.md
@@ -363,6 +363,7 @@ end
 * Constraint C1406, which prohibits the same module name from being used
   in a scope for both an intrinsic and a non-intrinsic module, is implemented
   as a portability warning only, not a hard error.
+* IBM @PROCESS directive is accepted but ignored.
 
 ## Preprocessing behavior
 

diff  --git a/flang/lib/Parser/prescan.cpp b/flang/lib/Parser/prescan.cpp
index 27b5597db4259..2bbf1d67eb626 100644
--- a/flang/lib/Parser/prescan.cpp
+++ b/flang/lib/Parser/prescan.cpp
@@ -777,8 +777,23 @@ bool Prescanner::PadOutCharacterLiteral(TokenSequence &tokens) {
   return false;
 }
 
+static bool IsAtProcess(const char *p) {
+  static const char pAtProc[]{"process"};
+  for (std::size_t i{0}; i < sizeof pAtProc - 1; ++i) {
+    if (ToLowerCaseLetter(*++p) != pAtProc[i])
+      return false;
+  }
+  return true;
+}
+
 bool Prescanner::IsFixedFormCommentLine(const char *start) const {
   const char *p{start};
+
+  // The @process directive must start in column 1.
+  if (*p == '@' && IsAtProcess(p)) {
+    return true;
+  }
+
   if (IsFixedFormCommentChar(*p) || *p == '%' || // VAX %list, %eject, &c.
       ((*p == 'D' || *p == 'd') &&
           !features_.IsEnabled(LanguageFeature::OldDebugLines))) {
@@ -810,6 +825,8 @@ const char *Prescanner::IsFreeFormComment(const char *p) const {
   p = SkipWhiteSpaceAndCComments(p);
   if (*p == '!' || *p == '\n') {
     return p;
+  } else if (*p == '@') {
+    return IsAtProcess(p) ? p : nullptr;
   } else {
     return nullptr;
   }

diff  --git a/flang/test/Parser/at-process.f b/flang/test/Parser/at-process.f
new file mode 100644
index 0000000000000..41b95044bfdc5
--- /dev/null
+++ b/flang/test/Parser/at-process.f
@@ -0,0 +1,20 @@
+! RUN: %flang_fc1 -fsyntax-only %s 2>&1 | FileCheck %s
+
+! Test ignoring @PROCESS directive in fixed source form
+
+ at process opt(3)
+ at process	opt(0)
+ at process
+ at processopt(3)
+      subroutine f()
+c at process
+      end
+
+!CHECK: Character in fixed-form label field must be a digit
+@
+
+!CHECK: Character in fixed-form label field must be a digit
+ at proce 
+
+!CHECK: Character in fixed-form label field must be a digit
+ at precoss 

diff  --git a/flang/test/Parser/at-process.f90 b/flang/test/Parser/at-process.f90
new file mode 100644
index 0000000000000..cd5b2acf3f3e0
--- /dev/null
+++ b/flang/test/Parser/at-process.f90
@@ -0,0 +1,23 @@
+! RUN: not %flang_fc1 -fsyntax-only %s 2>&1 | FileCheck %s
+
+! Test ignoring @PROCESS directive in free source form
+
+ at process opt(3)
+ at process	opt(0)
+      @process strict
+ at processopt(3)
+subroutine f()
+print *, "@process"
+   ! @process
+end subroutine f
+
+!CHECK: error: expected '('
+ at p
+
+!CHECK: error: expected '('
+ at proce
+
+!CHECK: error: expected '('
+ at precoss
+end
+