From 60354f5e2ddcfcc8493e001052ba93641a786036 Mon Sep 17 00:00:00 2001
From: drmortalwombat <90205530+drmortalwombat@users.noreply.github.com>
Date: Mon, 6 Sep 2021 21:13:48 +0200
Subject: [PATCH] Implemented static const int/float/bool etc constat
 propagation

---
 README.md                  |  1 -
 autotest/autotest.bat      |  3 +++
 autotest/staticconsttest.c | 20 ++++++++++++++++++++
 oscar64/Parser.cpp         | 24 +++++++++++++++++++++---
 oscar64/Scanner.cpp        |  6 ++++++
 oscar64/Scanner.h          |  2 ++
 6 files changed, 52 insertions(+), 4 deletions(-)
 create mode 100644 autotest/staticconsttest.c

diff --git a/README.md b/README.md
index 222bb7e..48f6827 100644
--- a/README.md
+++ b/README.md
@@ -47,7 +47,6 @@ The first release of the compiler is severely limited considering it is only two
 
 * All global variables are considered volatile
 * No loop opmtimization
-* Static const not propagated
 * Poor bookeeping of callee saved registers
 * Missing livetime reduction of intermediates
 * No block domination analysis
diff --git a/autotest/autotest.bat b/autotest/autotest.bat
index 1d2adc2..afc379c 100644
--- a/autotest/autotest.bat
+++ b/autotest/autotest.bat
@@ -27,6 +27,9 @@ if %errorlevel% neq 0 goto :error
 ..\release\oscar64 -i=../include -rt=../include/crt.c -e floatmultest.c
 if %errorlevel% neq 0 goto :error
 
+..\release\oscar64 -i=../include -rt=../include/crt.c -e staticconsttest.c
+if %errorlevel% neq 0 goto :error
+
 exit /b 0
 :error
 echo Failed with error #%errorlevel%.
diff --git a/autotest/staticconsttest.c b/autotest/staticconsttest.c
new file mode 100644
index 0000000..1c703f2
--- /dev/null
+++ b/autotest/staticconsttest.c
@@ -0,0 +1,20 @@
+#include <stdio.h>
+#include <assert.h>
+
+static const int size = 100;
+
+int main(void)
+{
+	int	a[size];
+
+	for(int i=0; i<size; i++)
+		a[i] = i;
+
+	int s = 0;
+	for(int i=0; i<size; i++)
+		s += a[i];
+
+	assert(s == 4950);
+
+	return 0;
+}
diff --git a/oscar64/Parser.cpp b/oscar64/Parser.cpp
index bd0ded3..c6452f2 100644
--- a/oscar64/Parser.cpp
+++ b/oscar64/Parser.cpp
@@ -44,6 +44,14 @@ Declaration* Parser::ParseBaseTypeDeclaration(uint32 flags)
 
 		break;
 
+	case TK_STATIC:
+		mScanner->NextToken();
+		return ParseBaseTypeDeclaration(flags | DTF_STATIC);
+
+	case TK_EXTERN:
+		mScanner->NextToken();
+		return ParseBaseTypeDeclaration(flags | DTF_EXTERN);
+
 	case TK_CONST:
 		mScanner->NextToken();
 		return ParseBaseTypeDeclaration(flags | DTF_CONST);
@@ -638,6 +646,8 @@ Declaration* Parser::ParseDeclaration(bool variable)
 		{
 			if (variable)
 			{
+				ndec->mFlags |= ndec->mBase->mFlags & (DTF_CONST | DTF_STATIC | DTF_VOLATILE | DTF_EXTERN);
+
 				if (ndec->mBase->mType == DT_TYPE_FUNCTION)
 					ndec->mType = DT_CONST_FUNCTION;
 
@@ -783,6 +793,7 @@ Expression* Parser::ParseSimpleExpression(void)
 	case TK_VOLATILE:
 	case TK_STRUCT:
 	case TK_TYPEDEF:
+	case TK_STATIC:
 		exp = ParseDeclarationExpression();
 		break;
 	case TK_INTEGER:
@@ -885,9 +896,16 @@ Expression* Parser::ParseSimpleExpression(void)
 			}
 			else if (dec->mType == DT_VARIABLE || dec->mType == DT_ARGUMENT)
 			{
-				exp = new Expression(mScanner->mLocation, EX_VARIABLE);
-				exp->mDecValue = dec;
-				exp->mDecType = dec->mBase;
+				if ((dec->mFlags & DTF_STATIC) && (dec->mFlags & DTF_CONST) && dec->mValue && dec->mBase->IsNumericType())
+				{
+					exp = dec->mValue;
+				}
+				else
+				{
+					exp = new Expression(mScanner->mLocation, EX_VARIABLE);
+					exp->mDecValue = dec;
+					exp->mDecType = dec->mBase;
+				}
 				mScanner->NextToken();
 			}
 			else if (dec->mType <= DT_TYPE_FUNCTION)
diff --git a/oscar64/Scanner.cpp b/oscar64/Scanner.cpp
index 463297d..3d3e076 100644
--- a/oscar64/Scanner.cpp
+++ b/oscar64/Scanner.cpp
@@ -38,6 +38,8 @@ const char* TokenNames[] = {
 		"'union'",
 		"'enum'",
 		"'sizeof'",
+		"'static'",
+		"'extern'",
 
 		"__asm",
 
@@ -958,6 +960,10 @@ void Scanner::NextRawToken(void)
 					mToken = TK_SIZEOF;
 				else if (!strcmp(tkident, "typedef"))
 					mToken = TK_TYPEDEF;
+				else if (!strcmp(tkident, "static"))
+					mToken = TK_STATIC;
+				else if (!strcmp(tkident, "extern"))
+					mToken = TK_EXTERN;
 				else if (!strcmp(tkident, "__asm"))
 					mToken = TK_ASM;
 				else
diff --git a/oscar64/Scanner.h b/oscar64/Scanner.h
index 1096749..dacb53b 100644
--- a/oscar64/Scanner.h
+++ b/oscar64/Scanner.h
@@ -38,6 +38,8 @@ enum Token
 	TK_UNION,
 	TK_ENUM,
 	TK_SIZEOF,
+	TK_STATIC,
+	TK_EXTERN,
 
 	TK_ASM,