PR modula2/110125 variables reported as uninitialized when set inside WITH

PR modula2/110125 variables reported as uninitialized when set inside WITH

The modula-2 static analysis incorrectly identifies variables as
uninitialized if they are initialized within a WITH statement.  This bug
fix re-implements the variable static analysis and will detect simple
pointer record fields being accessed before being initialized.
The static analysis is limited to the first basic block in a procedure.
It does not check variant records, arrays or sets.  A new option
-Wuninit-variable-checking will turn on the new semantic checking
(-Wall also enables the new checking).

gcc/ChangeLog:

	PR modula2/110125
	* doc/gm2.texi (Semantic checking): Include examples using
	-Wuninit-variable-checking.

gcc/m2/ChangeLog:

	PR modula2/110125
	* Make-lang.in (GM2-COMP-BOOT-DEFS): Add M2SymInit.def.
	(GM2-COMP-BOOT-MODS): Add M2SymInit.mod.
	* gm2-compiler/M2BasicBlock.mod: Formatting changes.
	* gm2-compiler/M2Code.mod: Remove import of VariableAnalysis from
	M2Quads.  Import VariableAnalysis from M2SymInit.mod.
	* gm2-compiler/M2GCCDeclare.mod (PrintVerboseFromList):
	Add debugging print for a component.
	(TypeConstFullyDeclared): Call RememberType for every type.
	* gm2-compiler/M2GenGCC.mod (CodeReturnValue): Add parameter to
	GetQuadOtok.
	(CodeBecomes): Add parameter to GetQuadOtok.
	(CodeXIndr): Add parameter to GetQuadOtok.
	* gm2-compiler/M2Optimize.mod (ReduceBranch): Reformat and
	preserve operand token positions when reducing the branch
	quadruples.
	(ReduceGoto): Reformat.
	(FoldMultipleGoto): Reformat.
	(KnownReachable): Reformat.
	* gm2-compiler/M2Options.def (UninitVariableChecking): New
	variable declared and exported.
	(SetUninitVariableChecking): New procedure.
	* gm2-compiler/M2Options.mod (SetWall): Set
	UninitVariableChecking.
	(SetUninitVariableChecking): New procedure.
	* gm2-compiler/M2Quads.def (PutQuadOtok): Exported and declared.
	(VariableAnalysis): Removed.
	* gm2-compiler/M2Quads.mod (PutQuadOtok): New procedure.
	(doVal): Reformatted.
	(MarkAsWrite): Reformatted.
	(MarkArrayAsWritten): Reformatted.
	(doIndrX): Use PutQuadOtok.
	(MakeRightValue): Use GenQuadOtok.
	(MakeLeftValue): Use GenQuadOtok.
	(CheckReadBeforeInitialized): Remove.
	(IsNeverAltered): Reformat.
	(DebugLocation): New procedure.
	(BuildDesignatorPointer): Use GenQuadO to preserve operand token
	position.
	(BuildRelOp): Use GenQuadOtok ditto.
	* gm2-compiler/SymbolTable.def (VarCheckReadInit): New procedure.
	(VarInitState): New procedure.
	(PutVarInitialized): New procedure.
	(PutVarFieldInitialized): New procedure function.
	(GetVarFieldInitialized): New procedure function.
	(PrintInitialized): New procedure.
	* gm2-compiler/SymbolTable.mod (VarCheckReadInit): New procedure.
	(VarInitState): New procedure.
	(PutVarInitialized): New procedure.
	(PutVarFieldInitialized): New procedure function.
	(GetVarFieldInitialized): New procedure function.
	(PrintInitialized): New procedure.
	(LRInitDesc): New type.
	(SymVar): InitState new field.
	(MakeVar): Initialize InitState.
	* gm2-gcc/m2options.h (M2Options_SetUninitVariableChecking):
	New function declaration.
	* gm2-lang.cc (gm2_langhook_handle_option): Detect
	OPT_Wuninit_variable_checking and call SetUninitVariableChecking.
	* lang.opt: Add Wuninit-variable-checking.
	* gm2-compiler/M2SymInit.def: New file.
	* gm2-compiler/M2SymInit.mod: New file.

gcc/testsuite/ChangeLog:

	PR modula2/110125
	* gm2/switches/uninit-variable-checking/fail/testinit.mod: New test.
	* gm2/switches/uninit-variable-checking/fail/testlarge.mod: New test.
	* gm2/switches/uninit-variable-checking/fail/testlarge2.mod: New test.
	* gm2/switches/uninit-variable-checking/fail/testrecinit.mod: New test.
	* gm2/switches/uninit-variable-checking/fail/testrecinit2.mod: New test.
	* gm2/switches/uninit-variable-checking/fail/testrecinit5.mod: New test.
	* gm2/switches/uninit-variable-checking/fail/testsmallrec.mod: New test.
	* gm2/switches/uninit-variable-checking/fail/testsmallrec2.mod: New test.
	* gm2/switches/uninit-variable-checking/fail/testsmallvec.mod: New test.
	* gm2/switches/uninit-variable-checking/fail/testvarinit.mod: New test.
	* gm2/switches/uninit-variable-checking/fail/testwithnoptr.mod: New test.
	* gm2/switches/uninit-variable-checking/fail/testwithptr.mod: New test.
	* gm2/switches/uninit-variable-checking/fail/testwithptr2.mod: New test.
	* gm2/switches/uninit-variable-checking/fail/testwithptr3.mod: New test.
	* gm2/switches/uninit-variable-checking/pass/testrecinit3.mod: New test.
	* gm2/switches/uninit-variable-checking/pass/testrecinit5.mod: New test.
	* gm2/switches/uninit-variable-checking/pass/testsmallrec.mod: New test.
	* gm2/switches/uninit-variable-checking/pass/testsmallrec2.mod: New test.
	* gm2/switches/uninit-variable-checking/pass/testvarinit.mod: New test.
	* gm2/switches/uninit-variable-checking/pass/testwithptr.mod: New test.
	* gm2/switches/uninit-variable-checking/pass/testwithptr2.mod: New test.
	* gm2/switches/uninit-variable-checking/pass/testwithptr3.mod: New test.

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