PR modula2/113889 Incorrect constant string value if declared in a definition module

This patch fixes a bug exposed when a constant string is declared in a
definition module and imported by a program module.  The bug fix
was to defer the string assignment and concatenation until quadruples
were generated.  The conststring symbol has a known field which
must be checked prior to retrieving the string contents.

gcc/m2/ChangeLog:

	PR modula2/113889
	* gm2-compiler/M2ALU.mod (StringFitsArray): Add tokeno parameter
	to GetStringLength.
	(InitialiseArrayOfCharWithString): Add tokeno parameter to
	GetStringLength.
	(CheckGetCharFromString): Add tokeno parameter to GetStringLength.
	* gm2-compiler/M2Const.mod (constResolveViaMeta): Replace
	PutConstString with PutConstStringKnown.
	* gm2-compiler/M2GCCDeclare.mod (DeclareCharConstant): Add tokenno
	parameter and add assert.  Use tokenno to generate location.
	(DeclareStringConstant): Add tokenno and add asserts.
	Add tokenno parameter to calls to GetStringLength.
	(PromoteToString): Add assert and add tokenno parameter to
	GetStringLength.
	(PromoteToCString): Add assert and add tokenno parameter to
	GetStringLength.
	(DeclareConstString): New procedure function.
	(TryDeclareConst): Remove size local variable.
	Check IsConstStringKnown.
	Call DeclareConstString.
	(PrintString): New procedure.
	(PrintVerboseFromList): Call PrintString.
	(CheckResolveSubrange): Check IsConstStringKnown before creating
	subrange for char or issuing an error.
	* gm2-compiler/M2GenGCC.mod (ResolveConstantExpressions): Add
	StringLengthOp, StringConvertM2nulOp, StringConvertCnulOp case
	clauses.
	(FindSize): Add assert IsConstStringKnown.
	(StringToChar): New variable tokenno.
	Add tokenno parameter to GetStringLength.
	(FoldStringLength): New procedure.
	(FoldStringConvertM2nul): New procedure.
	(FoldStringConvertCnul): New procedure.
	(CodeAddr): Add tokenno parameter.
	Replace CurrentQuadToken with tokenno.
	Add tokenno parameter to GetStringLength.
	(PrepareCopyString): Rewrite.
	(IsConstStrKnown): New procedure function.
	(FoldAdd): Detect conststring op2 and op3 which are known and
	concat.  Place result into op1.
	(FoldStandardFunction): Pass tokenno as a parameter to
	GetStringLength.
	(CodeXIndr): Rewrite comment.
	Rename op1 to left, op3 to right.
	Pass rightpos to GetStringLength.
	* gm2-compiler/M2Quads.def (QuadrupleOp): Add
	StringConvertCnulOp, StringConvertM2nulOp and StringLengthOp.
	* gm2-compiler/M2Quads.mod (import): Remove MakeConstLitString.
	Add CopyConstString and PutConstStringKnown.
	(IsInitialisingConst): Add StringConvertCnulOp,
	StringConvertM2nulOp and StringLengthOp.
	(callRequestDependant): Replace MakeConstLitString with
	MakeConstString.
	(DeferMakeConstStringCnul): New procedure function.
	(DeferMakeConstStringM2nul): New procedure function.
	(CheckParameter): Add early return if the string const is unknown.
	(DescribeType): Add token parameter to GetStringLength.
	Check for IsConstStringKnown.
	(ManipulateParameters): Use DeferMakeConstStringCnul and
	DeferMakeConstStringM2nul.
	(MakeLengthConst): Remove and replace with...
	(DeferMakeLengthConst): ... this.
	(doBuildBinaryOp): Create ConstString and set it to contents
	unknown.
	Check IsConstStringKnown before generating error message.
	(WriteQuad): Add StringConvertCnulOp, StringConvertM2nulOp and
	StringLengthOp.
	(WriteOperator): Add StringConvertCnulOp, StringConvertM2nulOp and
	StringLengthOp.
	* gm2-compiler/M2SymInit.mod (CheckReadBeforeInitQuad): Add
	StringConvertCnulOp, StringConvertM2nulOp and StringLengthOp.
	* gm2-compiler/NameKey.mod (LengthKey): Allow NulName to return 0.
	* gm2-compiler/P2SymBuild.mod (BuildString): Replace
	MakeConstLitString with MakeConstString.
	(DetermineType): Replace PutConstString with PutConstStringKnown.
	* gm2-compiler/SymbolTable.def (MakeConstVar): Tidy up comment.
	(MakeConstLitString): Remove.
	(MakeConstString): New procedure function.
	(MakeConstStringCnul): New procedure function.
	(MakeConstStringM2nul): New procedure function.
	(PutConstStringKnown): New procedure.
	(CopyConstString): New procedure.
	(IsConstStringKnown): New procedure function.
	(IsConstStringM2): New procedure function.
	(IsConstStringC): New procedure function.
	(IsConstStringM2nul): New procedure function.
	(IsConstStringCnul): New procedure function.
	(GetStringLength): Add token parameter.
	(PutConstString): Remove.
	(GetConstStringM2): Remove.
	(GetConstStringC): Remove.
	(GetConstStringM2nul): Remove.
	(GetConstStringCnul): Remove.
	(MakeConstStringC): Remove.
	* gm2-compiler/SymbolTable.mod (SymConstString): Remove
	M2Variant, NulM2Variant, CVariant, NulCVariant.
	Add Known.
	(CheckAnonymous): Replace $$ with __anon.
	(IsNameAnonymous): Replace $$ with __anon.
	(MakeConstVar): Detect whether the name is nul and treat as
	a temporary constant.
	(MakeConstLitString): Remove.
	(BackFillString): Remove.
	(InitConstString): Rewrite.
	(GetConstStringM2): Remove.
	(GetConstStringC): Remove.
	(GetConstStringContent): New procedure function.
	(GetConstStringM2nul): Remove.
	(GetConstStringCnul): Remove.
	(MakeConstStringCnul): Rewrite.
	(MakeConstStringM2nul): Rewrite.
	(MakeConstStringC): Remove.
	(MakeConstString): Rewrite.
	(PutConstStringKnown): New procedure.
	(CopyConstString): New procedure.
	(PutConstString): Remove.
	(IsConstStringKnown): New procedure function.
	(IsConstStringM2): New procedure function.
	(IsConstStringC): Rewrite.
	(IsConstStringM2nul): Rewrite.
	(IsConstStringCnul): Rewrite.
	(GetConstStringKind): New procedure function.
	(GetString): Check Known.
	(GetStringLength): Add token parameter and check Known.

gcc/testsuite/ChangeLog:

	PR modula2/113889
	* gm2/pim/run/pass/pim-run-pass.exp: Add filter for
	constdef.mod.
	* gm2/extensions/run/pass/callingc2.mod: New test.
	* gm2/extensions/run/pass/callingc3.mod: New test.
	* gm2/extensions/run/pass/callingc4.mod: New test.
	* gm2/extensions/run/pass/callingc5.mod: New test.
	* gm2/extensions/run/pass/callingc6.mod: New test.
	* gm2/extensions/run/pass/callingc7.mod: New test.
	* gm2/extensions/run/pass/callingc8.mod: New test.
	* gm2/extensions/run/pass/fixedarray.mod: New test.
	* gm2/extensions/run/pass/fixedarray2.mod: New test.
	* gm2/pim/run/pass/constdef.def: New test.
	* gm2/pim/run/pass/constdef.mod: New test.
	* gm2/pim/run/pass/testimportconst.mod: New test.

Signed-off-by: Gaius Mulley <gaiusmod2@gmail.com>