[OptTable] Refine how `printHelp` treats empty help texts

Currently, `printHelp` behaves differently for options that:
  * do not define `HelpText` (such options _are not printed_), and
  * define its `HelpText` as `HelpText<"">` (such options _are printed_).
In practice, both approaches lead to no help text and `printHelp` should
treat them consistently. This patch addresses that by making
`printHelpt` check the length of the help text to be printed.

All affected tests have been updated accordingly. The option definitions
for llvm-cvtres have been updated with a short description or "Not
  implemented" for options that are ignored by the tool.

Differential Revision: https://reviews.llvm.org/D107557

5 files changed, 17 insertions, 32 deletions

diff --git a/flang/test/Driver/driver-help-hidden.f90 b/flang/test/Driver/driver-help-hidden.f90
index 9e63408b..c91fdaa 100644
--- a/flang/test/Driver/driver-help-hidden.f90
+++ b/flang/test/Driver/driver-help-hidden.f90
@@ -39,12 +39,7 @@
 ! CHECK-NEXT:                        Specify where to find the compiled intrinsic modules
 ! CHECK-NEXT: -flarge-sizes          Use INTEGER(KIND=8) for the result type in size-related intrinsics
 ! CHECK-NEXT: -flogical-abbreviations Enable logical abbreviations
-! CHECK-NEXT: -fno-backslash
 ! CHECK-NEXT: -fno-color-diagnostics  Disable colors in diagnostics
-! CHECK-NEXT: -fno-implicit-none
-! CHECK-NEXT: -fno-logical-abbreviations
-! CHECK-NEXT: {{[[:space:]]$}}
-! CHECK-NEXT: -fno-xor-operator
 ! CHECK-NEXT: -fopenacc              Enable OpenACC
 ! CHECK-NEXT: -fopenmp               Parse OpenMP pragmas and generate parallel code.
 ! CHECK-NEXT: -fxor-operator         Enable .XOR. as a synonym of .NEQV.
diff --git a/flang/test/Driver/driver-help.f90 b/flang/test/Driver/driver-help.f90
index 441cf73..b895dc4 100644
--- a/flang/test/Driver/driver-help.f90
+++ b/flang/test/Driver/driver-help.f90
@@ -39,12 +39,7 @@
 ! HELP-NEXT:                        Specify where to find the compiled intrinsic modules
 ! HELP-NEXT: -flarge-sizes          Use INTEGER(KIND=8) for the result type in size-related intrinsics
 ! HELP-NEXT: -flogical-abbreviations Enable logical abbreviations
-! HELP-NEXT: -fno-backslash
 ! HELP-NEXT: -fno-color-diagnostics  Disable colors in diagnostics
-! HELP-NEXT: -fno-implicit-none
-! HELP-NEXT: -fno-logical-abbreviations
-! HELP-NEXT: {{[[:space:]]$}}
-! HELP-NEXT: -fno-xor-operator
 ! HELP-NEXT: -fopenacc              Enable OpenACC
 ! HELP-NEXT: -fopenmp               Parse OpenMP pragmas and generate parallel code.
 ! HELP-NEXT: -fxor-operator         Enable .XOR. as a synonym of .NEQV.
@@ -73,8 +68,6 @@
 ! HELP-FC1-NEXT: -E                     Only run the preprocessor
 ! HELP-FC1-NEXT: -falternative-parameter-statement
 ! HELP-FC1-NEXT: Enable the old style PARAMETER statement
-! HELP-FC1-NEXT: -fanalyzed-objects-for-unparse
-! HELP-FC1-NEXT: {{[[:space:]]$}}
 ! HELP-FC1-NEXT: -fbackslash            Specify that backslash in string introduces an escape character
 ! HELP-FC1-NEXT: -fdebug-dump-all       Dump symbols and the parse tree after the semantic checks
 ! HELP-FC1-NEXT: -fdebug-dump-parse-tree-no-sema
@@ -110,12 +103,7 @@
 ! HELP-FC1-NEXT: -flogical-abbreviations Enable logical abbreviations
 ! HELP-FC1-NEXT: -fno-analyzed-objects-for-unparse
 ! HELP-FC1-NEXT:                        Do not use the analyzed objects when unparsing
-! HELP-FC1-NEXT: -fno-backslash
-! HELP-FC1-NEXT: -fno-implicit-none
-! HELP-FC1-NEXT: -fno-logical-abbreviations
-! HELP-FC1-NEXT: {{[[:space:]]$}}
 ! HELP-FC1-NEXT: -fno-reformat          Dump the cooked character stream in -E mode
-! HELP-FC1-NEXT: -fno-xor-operator
 ! HELP-FC1-NEXT: -fopenacc              Enable OpenACC
 ! HELP-FC1-NEXT: -fopenmp               Parse OpenMP pragmas and generate parallel code.
 ! HELP-FC1-NEXT: -fxor-operator         Enable .XOR. as a synonym of .NEQV.
diff --git a/llvm/lib/Option/OptTable.cpp b/llvm/lib/Option/OptTable.cpp
index f5bf166..a994a42 100644
--- a/llvm/lib/Option/OptTable.cpp
+++ b/llvm/lib/Option/OptTable.cpp
@@ -654,7 +654,7 @@ void OptTable::printHelp(raw_ostream &OS, const char *Usage, const char *Title,
         HelpText = getOptionHelpText(Alias.getID());
     }
 
-    if (HelpText) {
+    if (HelpText && (strlen(HelpText) != 0)) {
       const char *HelpGroup = getOptionHelpGroup(*this, Id);
       const std::string &OptName = getOptionHelpName(*this, Id);
       GroupedOptionHelp[HelpGroup].push_back({OptName, HelpText});
diff --git a/llvm/test/tools/llvm-cvtres/help.test b/llvm/test/tools/llvm-cvtres/help.test
index 3be7c96..a3817e9 100644
--- a/llvm/test/tools/llvm-cvtres/help.test
+++ b/llvm/test/tools/llvm-cvtres/help.test
@@ -4,11 +4,13 @@
 ; HELP_TEST: 	  OVERVIEW: Resource Converter
 ; HELP_TEST-DAG:  USAGE: llvm-cvtres [options] file...
 ; HELP_TEST-DAG:  OPTIONS:
-; HELP_TEST-NEXT:   /DEFINE:symbol 
-; HELP_TEST-NEXT:   /FOLDDUPS:     
+; HELP_TEST-NEXT:   /DEFINE:symbol Not implemented
+; HELP_TEST-NEXT:   /FOLDDUPS: Not implemented
+; HELP_TEST-NEXT:   /HELP Display available options
 ; HELP_TEST-NEXT:   /MACHINE:{ARM|ARM64|EBC|IA64|X64|X86}
-; HELP_TEST-DAG:    /NOLOGO        
-; HELP_TEST-NEXT:   /OUT:filename  
-; HELP_TEST-NEXT:   /READONLY      
+; HELP_TEST-NEXT:   Machine architecture
+; HELP_TEST-DAG:    /NOLOGO Not implemented
+; HELP_TEST-NEXT:   /OUT:filename Output file
+; HELP_TEST-NEXT:   /READONLY Not implemented
 ; HELP_TEST-NEXT:   /TIMESTAMP:<value> Timestamp for coff header, defaults to current time
-; HELP_TEST-NEXT:   /VERBOSE
+; HELP_TEST-NEXT:   /VERBOSE Use verbose output
diff --git a/llvm/tools/llvm-cvtres/Opts.td b/llvm/tools/llvm-cvtres/Opts.td
index 8687d47..21d5837 100644
--- a/llvm/tools/llvm-cvtres/Opts.td
+++ b/llvm/tools/llvm-cvtres/Opts.td
@@ -2,14 +2,14 @@ include "llvm/Option/OptParser.td"
 
 // All the switches can be preceded by either '/' or '-'.
 
-def DEFINE : Joined<["/", "-"], "DEFINE:">, HelpText<"">, MetaVarName<"symbol">;
-def FOLDDUPS : Flag<["/", "-"], "FOLDDUPS:">, HelpText<"">;
-def MACHINE : Joined<["/", "-"], "MACHINE:">, HelpText<"">, MetaVarName<"{ARM|ARM64|EBC|IA64|X64|X86}">;
-def NOLOGO : Flag<["/", "-"], "NOLOGO">, HelpText<"">;
-def OUT : Joined<["/", "-"], "OUT:">, HelpText<"">, MetaVarName<"filename">;
-def READONLY : Flag<["/", "-"], "READONLY">, HelpText<"">;
-def VERBOSE : Flag<["/", "-"], "VERBOSE">, HelpText<"">;
-def HELP : Flag<["/", "-"], "HELP">;
+def DEFINE : Joined<["/", "-"], "DEFINE:">, HelpText<"Not implemented">, MetaVarName<"symbol">;
+def FOLDDUPS : Flag<["/", "-"], "FOLDDUPS:">, HelpText<"Not implemented">;
+def MACHINE : Joined<["/", "-"], "MACHINE:">, HelpText<"Machine architecture">, MetaVarName<"{ARM|ARM64|EBC|IA64|X64|X86}">;
+def NOLOGO : Flag<["/", "-"], "NOLOGO">, HelpText<"Not implemented">;
+def OUT : Joined<["/", "-"], "OUT:">, HelpText<"Output file">, MetaVarName<"filename">;
+def READONLY : Flag<["/", "-"], "READONLY">, HelpText<"Not implemented">;
+def VERBOSE : Flag<["/", "-"], "VERBOSE">, HelpText<"Use verbose output">;
+def HELP : Flag<["/", "-"], "HELP">, HelpText<"Display available options">;
 def H : Flag<["/", "-"], "H">, Alias<HELP>;
 def HELP_Q : Flag<["/?", "-?"], "">, Alias<HELP>;