[FileCheck] Add support for hex alternate form in FileCheck

Add printf-style alternate form flag to prefix hex number with 0x when
present. This works on both empty numeric expression (e.g. variable
definition from input) and when matching a numeric expression. The
syntax is as follows:

[[#%#<precision specifier><format specifier>, ...]

where <precision specifier> and <format specifier> are optional and ...
can be a variable definition or not with an empty expression or not.

This feature was requested in https://reviews.llvm.org/D81144#2075532
for llvm/test/MC/ELF/gen-dwarf64.s

Reviewed By: jdenny

Differential Revision: https://reviews.llvm.org/D97845

1 files changed, 5 insertions, 1 deletions

diff --git a/llvm/lib/FileCheck/FileCheckImpl.h b/llvm/lib/FileCheck/FileCheckImpl.h
index 05b2a52..1966b0e 100644
--- a/llvm/lib/FileCheck/FileCheckImpl.h
+++ b/llvm/lib/FileCheck/FileCheckImpl.h
@@ -54,6 +54,8 @@ struct ExpressionFormat {
 private:
   Kind Value;
   unsigned Precision = 0;
+  /// printf-like "alternate form" selected.
+  bool AlternateForm = false;
 
 public:
   /// Evaluates a format to true if it can be used in a match.
@@ -63,7 +65,7 @@ public:
   /// their kinds and precision are the same.
   bool operator==(const ExpressionFormat &Other) const {
     return Value != Kind::NoFormat && Value == Other.Value &&
-           Precision == Other.Precision;
+           Precision == Other.Precision && AlternateForm == Other.AlternateForm;
   }
 
   bool operator!=(const ExpressionFormat &Other) const {
@@ -81,6 +83,8 @@ public:
   explicit ExpressionFormat(Kind Value) : Value(Value), Precision(0){};
   explicit ExpressionFormat(Kind Value, unsigned Precision)
       : Value(Value), Precision(Precision){};
+  explicit ExpressionFormat(Kind Value, unsigned Precision, bool AlternateForm)
+      : Value(Value), Precision(Precision), AlternateForm(AlternateForm){};
 
   /// \returns a wildcard regular expression string that matches any value in
   /// the format represented by this instance and no other value, or an error