From 51e34acab11aaa0077c14f432fd9cc6dbfb5a512 Mon Sep 17 00:00:00 2001
From: George Koehler <kernigh@gmail.com>
Date: Thu, 24 Oct 2019 14:08:52 -0400
Subject: [PATCH] Add a syntax to declare functions in a top table

Use the new syntax in the mips, pdp, powerpc tables to declare
functions before calling them.  These declarations prevent compiler
warnings about implicitly declaring functions.  They also provide
prototypes of the function parameters.

Also fix a warning in the powerpc table: use `bsearch(...) != NULL` to
avoid converting the pointer from bsearch() to an int.

The syntax for topgen is a block `{...}` among the parameters in the
top table.  It looks like the syntax of LLgen, but topgen doesn't
allow nested blocks, so declarations like `struct whatever {...};`
don't work.  The token OPEN_BRACKET that begins a declaration_block
doesn't conflict with the LETTER that begins a parameter_line or the
'%' that begins a separator.

Because a block writes a #line command to gen.h, a parameter line now
also writes a #line command to gen.h, so it doesn't get a wrong line
number from a previous block.
---
 mach/mips/top/table    |  4 ++++
 mach/pdp/top/table     |  7 +++++++
 mach/powerpc/top/table |  9 ++++++++-
 util/topgen/topgen.g   | 39 ++++++++++++++++++++++++++++++++++-----
 4 files changed, 53 insertions(+), 6 deletions(-)

diff --git a/mach/mips/top/table b/mach/mips/top/table
index c0037f54d..f77447316 100644
--- a/mach/mips/top/table
+++ b/mach/mips/top/table
@@ -4,6 +4,10 @@
 MAXOP 5;
 LABEL_STARTER '.';
 
+{
+int plus(const char *, const char *, const char *);
+}
+
 %%;
 
 X, Y, Z                      { TRUE };
diff --git a/mach/pdp/top/table b/mach/pdp/top/table
index 7de05c47c..eab213b6a 100644
--- a/mach/pdp/top/table
+++ b/mach/pdp/top/table
@@ -6,6 +6,13 @@ MAXOP		2;
 LABEL_STARTER	'I';
 OPC_TERMINATOR	' ';
 
+{
+int no_side_effects(char *);
+int is_register(char *);
+int is_scratchreg(char *);
+int carry_dead(char *);
+}
+
 %%;
 
 /* useful addressing modes: */
diff --git a/mach/powerpc/top/table b/mach/powerpc/top/table
index 196cae128..6b4a8b73f 100644
--- a/mach/powerpc/top/table
+++ b/mach/powerpc/top/table
@@ -4,6 +4,13 @@
 MAXOP 5;
 LABEL_STARTER '.';
 
+{
+int not_using_sp(const char *);
+int positive(const char *);
+int lift(const char *);
+int plus(const char *, const char *, const char *);
+}
+
 %%;
 
 L1, L2, L3, L4, L5  { not_using_sp(VAL) };
@@ -160,7 +167,7 @@ static int liftcmp(const void *a, const void *b) {
 int lift(const char *s) {
 	return bsearch(&s, liftables,
 	    sizeof(liftables) / sizeof(liftables[0]),
-	    sizeof(liftables[0]), liftcmp);
+	    sizeof(liftables[0]), liftcmp) != NULL;
 }
 
 
diff --git a/util/topgen/topgen.g b/util/topgen/topgen.g
index 1d0284d63..516f020ca 100644
--- a/util/topgen/topgen.g
+++ b/util/topgen/topgen.g
@@ -41,14 +41,14 @@ extern void error(char *s, char* s1);
 
 optim_description
 	{ struct symtab *p; } :
-	SPACE* parameter_line*
+	SPACE* parameters
 			{   p = findident("MAXOP",LOOKING,&deftable);
 			    if (p == 0) maxoperand = 2;	/* default */
 			    else maxoperand = p->s_num;
 			}
 	separator SPACE* mode_definitions
-	separator SPACE* patterns		
-	separator 
+	separator SPACE* patterns
+	separator
 			{   register int c;
 			    fprintf(genc, linedir, lineno, inpfile);
 			    while ((c = getc(input)) != EOF) {
@@ -57,17 +57,25 @@ optim_description
 			}
 ;
 
+parameters :
+	[ parameter_line | declaration_block ]*
+;
+
 parameter_line
-	{ struct symtab *p;} :
+	{ struct symtab *p;
+	  int lin;
+	} :
 	identifier
 			{   p = findident(idbuf,ENTERING,&deftable);}
 	SPACE
+			{   lin = lineno;}
 	value
 			{   p->s_num = atoi(buf);}
 			/* This action in fact only needed for MAXOP */
 	LINE_TERMINATOR
 	SPACE*
-			{   fprintf(genh,"#define %s %s\n",p->s_name,buf);}
+			{   fprintf(genh, linedir, lin, inpfile);
+			    fprintf(genh,"#define %s %s\n",p->s_name,buf);}
 ;
 
 value
@@ -89,6 +97,27 @@ value
 			{   *p1 = '\0';}
 ;
 
+declaration_block :
+	OPEN_BRACKET
+			{   fprintf(genh, linedir, lineno, inpfile);}
+	[
+	    [   LINE_TERMINATOR
+	    |   OPERAND_SEPARATOR
+	    |	PATTERN_SEPARATOR
+	    |	INSTRUCTION_SEPARATOR
+	    |   SPACE
+	    |	LETTER
+	    |	DIGIT
+	    |	OTHER
+	    |	'%'
+	    ]
+			{   putc(dot.t_attrib, genh);}
+	]*
+	CLOSE_BRACKET
+	SPACE*
+			{   putc('\n', genh);}
+;
+
 mode_definitions
 	{ int lin; } :
 			{   fputs("tok_chk(varno) {\n\tint r;\n", genc);