[llvm] export private symbols needed by unittests (#145767)

## Purpose
Export a small number of private LLVM symbols so that unit tests can
still build/run when LLVM is built as a Windows DLL or a shared library
with default hidden symbol visibility.

## Background
The effort to build LLVM as a WIndows DLL is tracked in #109483.
Additional context is provided in [this
discourse](https://discourse.llvm.org/t/psa-annotating-llvm-public-interface/85307).

Some LLVM unit tests use internal/private symbols that are not part of
LLVM's public interface. When building LLVM as a DLL or shared library
with default hidden symbol visibility, the symbols are not available
when the unit test links against the DLL or shared library.

This problem can be solved in one of two ways:
1. Export the private symbols from the DLL.
2. Link the unit tests against the intermediate static libraries instead
of the final LLVM DLL.

This PR applies option 1. Based on the discussion of option 2 in
#145448, this option is preferable.

## Overview
* Adds a new `LLVM_ABI_FOR_TEST` export macro, which is currently just
an alias for `LLVM_ABI`.
* Annotates the sub-set of symbols under `llvm/lib` that are required to
get unit tests building using the new macro.

1 files changed, 39 insertions, 29 deletions

diff --git a/llvm/lib/FileCheck/FileCheckImpl.h b/llvm/lib/FileCheck/FileCheckImpl.h
index 5cf5548..a08502e 100644
--- a/llvm/lib/FileCheck/FileCheckImpl.h
+++ b/llvm/lib/FileCheck/FileCheckImpl.h
@@ -19,6 +19,7 @@
 #include "llvm/ADT/StringMap.h"
 #include "llvm/ADT/StringRef.h"
 #include "llvm/FileCheck/FileCheck.h"
+#include "llvm/Support/Compiler.h"
 #include "llvm/Support/Error.h"
 #include "llvm/Support/SourceMgr.h"
 #include <map>
@@ -88,23 +89,24 @@ public:
   /// \returns a wildcard regular expression string that matches any value in
   /// the format represented by this instance and no other value, or an error
   /// if the format is NoFormat.
-  Expected<std::string> getWildcardRegex() const;
+  LLVM_ABI_FOR_TEST Expected<std::string> getWildcardRegex() const;
 
   /// \returns the string representation of \p Value in the format represented
   /// by this instance, or an error if conversion to this format failed or the
   /// format is NoFormat.
-  Expected<std::string> getMatchingString(APInt Value) const;
+  LLVM_ABI_FOR_TEST Expected<std::string> getMatchingString(APInt Value) const;
 
   /// \returns the value corresponding to string representation \p StrVal
   /// according to the matching format represented by this instance.
-  APInt valueFromStringRepr(StringRef StrVal, const SourceMgr &SM) const;
+  LLVM_ABI_FOR_TEST APInt valueFromStringRepr(StringRef StrVal,
+                                              const SourceMgr &SM) const;
 };
 
 /// Class to represent an overflow error that might result when manipulating a
 /// value.
 class OverflowError : public ErrorInfo<OverflowError> {
 public:
-  static char ID;
+  LLVM_ABI_FOR_TEST static char ID;
 
   std::error_code convertToErrorCode() const override {
     return std::make_error_code(std::errc::value_too_large);
@@ -115,10 +117,14 @@ public:
 
 /// Performs operation and \returns its result or an error in case of failure,
 /// such as if an overflow occurs.
-Expected<APInt> exprAdd(const APInt &Lhs, const APInt &Rhs, bool &Overflow);
-Expected<APInt> exprSub(const APInt &Lhs, const APInt &Rhs, bool &Overflow);
-Expected<APInt> exprMul(const APInt &Lhs, const APInt &Rhs, bool &Overflow);
-Expected<APInt> exprDiv(const APInt &Lhs, const APInt &Rhs, bool &Overflow);
+LLVM_ABI_FOR_TEST Expected<APInt> exprAdd(const APInt &Lhs, const APInt &Rhs,
+                                          bool &Overflow);
+LLVM_ABI_FOR_TEST Expected<APInt> exprSub(const APInt &Lhs, const APInt &Rhs,
+                                          bool &Overflow);
+LLVM_ABI_FOR_TEST Expected<APInt> exprMul(const APInt &Lhs, const APInt &Rhs,
+                                          bool &Overflow);
+LLVM_ABI_FOR_TEST Expected<APInt> exprDiv(const APInt &Lhs, const APInt &Rhs,
+                                          bool &Overflow);
 Expected<APInt> exprMax(const APInt &Lhs, const APInt &Rhs, bool &Overflow);
 Expected<APInt> exprMin(const APInt &Lhs, const APInt &Rhs, bool &Overflow);
 
@@ -169,7 +175,7 @@ private:
   StringRef VarName;
 
 public:
-  static char ID;
+  LLVM_ABI_FOR_TEST static char ID;
 
   UndefVarError(StringRef VarName) : VarName(VarName) {}
 
@@ -277,7 +283,7 @@ public:
 
 /// Class representing the use of a numeric variable in the AST of an
 /// expression.
-class NumericVariableUse : public ExpressionAST {
+class LLVM_ABI_FOR_TEST NumericVariableUse : public ExpressionAST {
 private:
   /// Pointer to the class instance for the variable this use is about.
   NumericVariable *Variable;
@@ -299,7 +305,7 @@ public:
 using binop_eval_t = Expected<APInt> (*)(const APInt &, const APInt &, bool &);
 
 /// Class representing a single binary operation in the AST of an expression.
-class BinaryOperation : public ExpressionAST {
+class LLVM_ABI_FOR_TEST BinaryOperation : public ExpressionAST {
 private:
   /// Left operand.
   std::unique_ptr<ExpressionAST> LeftOperand;
@@ -377,7 +383,7 @@ public:
   virtual Expected<std::string> getResultForDiagnostics() const = 0;
 };
 
-class StringSubstitution : public Substitution {
+class LLVM_ABI_FOR_TEST StringSubstitution : public Substitution {
 public:
   StringSubstitution(FileCheckPatternContext *Context, StringRef VarName,
                      size_t InsertIdx)
@@ -393,7 +399,7 @@ public:
   Expected<std::string> getResultForDiagnostics() const override;
 };
 
-class NumericSubstitution : public Substitution {
+class LLVM_ABI_FOR_TEST NumericSubstitution : public Substitution {
 private:
   /// Pointer to the class representing the expression whose value is to be
   /// substituted.
@@ -463,24 +469,24 @@ private:
 public:
   /// \returns the value of string variable \p VarName or an error if no such
   /// variable has been defined.
-  Expected<StringRef> getPatternVarValue(StringRef VarName);
+  LLVM_ABI_FOR_TEST Expected<StringRef> getPatternVarValue(StringRef VarName);
 
   /// Defines string and numeric variables from definitions given on the
   /// command line, passed as a vector of [#]VAR=VAL strings in
   /// \p CmdlineDefines. \returns an error list containing diagnostics against
   /// \p SM for all definition parsing failures, if any, or Success otherwise.
-  Error defineCmdlineVariables(ArrayRef<StringRef> CmdlineDefines,
-                               SourceMgr &SM);
+  LLVM_ABI_FOR_TEST Error
+  defineCmdlineVariables(ArrayRef<StringRef> CmdlineDefines, SourceMgr &SM);
 
   /// Create @LINE pseudo variable. Value is set when pattern are being
   /// matched.
-  void createLineVariable();
+  LLVM_ABI_FOR_TEST void createLineVariable();
 
   /// Undefines local variables (variables whose name does not start with a '$'
   /// sign), i.e. removes them from GlobalVariableTable and from
   /// GlobalNumericVariableTable and also clears the value of numeric
   /// variables.
-  void clearLocalVars();
+  LLVM_ABI_FOR_TEST void clearLocalVars();
 
 private:
   /// Makes a new numeric variable and registers it for destruction when the
@@ -506,7 +512,7 @@ private:
   SMRange Range;
 
 public:
-  static char ID;
+  LLVM_ABI_FOR_TEST static char ID;
 
   ErrorDiagnostic(SMDiagnostic &&Diag, SMRange Range)
       : Diagnostic(Diag), Range(Range) {}
@@ -536,7 +542,7 @@ public:
 
 class NotFoundError : public ErrorInfo<NotFoundError> {
 public:
-  static char ID;
+  LLVM_ABI_FOR_TEST static char ID;
 
   std::error_code convertToErrorCode() const override {
     return inconvertibleErrorCode();
@@ -660,7 +666,7 @@ public:
   FileCheckPatternContext *getContext() const { return Context; }
 
   /// \returns whether \p C is a valid first character for a variable name.
-  static bool isValidVarNameStart(char C);
+  LLVM_ABI_FOR_TEST static bool isValidVarNameStart(char C);
 
   /// Parsing information about a variable.
   struct VariableProperties {
@@ -673,8 +679,8 @@ public:
   /// is the name of a pseudo variable, or an error holding a diagnostic
   /// against \p SM if parsing fail. If parsing was successful, also strips
   /// \p Str from the variable name.
-  static Expected<VariableProperties> parseVariable(StringRef &Str,
-                                                    const SourceMgr &SM);
+  LLVM_ABI_FOR_TEST static Expected<VariableProperties>
+  parseVariable(StringRef &Str, const SourceMgr &SM);
   /// Parses \p Expr for a numeric substitution block at line \p LineNumber,
   /// or before input is parsed if \p LineNumber is None. Parameter
   /// \p IsLegacyLineExpr indicates whether \p Expr should be a legacy @LINE
@@ -685,7 +691,8 @@ public:
   /// successful, sets \p DefinedNumericVariable to point to the class
   /// representing the numeric variable defined in this numeric substitution
   /// block, or std::nullopt if this block does not define any variable.
-  static Expected<std::unique_ptr<Expression>> parseNumericSubstitutionBlock(
+  LLVM_ABI_FOR_TEST static Expected<std::unique_ptr<Expression>>
+  parseNumericSubstitutionBlock(
       StringRef Expr, std::optional<NumericVariable *> &DefinedNumericVariable,
       bool IsLegacyLineExpr, std::optional<size_t> LineNumber,
       FileCheckPatternContext *Context, const SourceMgr &SM);
@@ -696,8 +703,9 @@ public:
   /// global options that influence the parsing such as whitespace
   /// canonicalization, \p SM provides the SourceMgr used for error reports.
   /// \returns true in case of an error, false otherwise.
-  bool parsePattern(StringRef PatternStr, StringRef Prefix, SourceMgr &SM,
-                    const FileCheckRequest &Req);
+  LLVM_ABI_FOR_TEST bool parsePattern(StringRef PatternStr, StringRef Prefix,
+                                      SourceMgr &SM,
+                                      const FileCheckRequest &Req);
   struct Match {
     size_t Pos;
     size_t Len;
@@ -721,7 +729,8 @@ public:
   /// GlobalNumericVariableTable StringMap in the same class provides the
   /// current values of FileCheck numeric variables and is updated if this
   /// match defines new numeric values.
-  MatchResult match(StringRef Buffer, const SourceMgr &SM) const;
+  LLVM_ABI_FOR_TEST MatchResult match(StringRef Buffer,
+                                      const SourceMgr &SM) const;
   /// Prints the value of successful substitutions.
   void printSubstitutions(const SourceMgr &SM, StringRef Buffer,
                           SMRange MatchRange, FileCheckDiag::MatchType MatchTy,
@@ -732,8 +741,9 @@ public:
   bool hasVariable() const {
     return !(Substitutions.empty() && VariableDefs.empty());
   }
-  void printVariableDefs(const SourceMgr &SM, FileCheckDiag::MatchType MatchTy,
-                         std::vector<FileCheckDiag> *Diags) const;
+  LLVM_ABI_FOR_TEST void
+  printVariableDefs(const SourceMgr &SM, FileCheckDiag::MatchType MatchTy,
+                    std::vector<FileCheckDiag> *Diags) const;
 
   Check::FileCheckType getCheckTy() const { return CheckTy; }