[as] Add testcase to document that it reorders '.file' directives [#20]

This relates to commit bd12880 "Deal with
.file and .loc directives".

test/as/debug/directive-file-1-sum.c

@@ -0,0 +1,5 @@
+inline __attribute__((always_inline))
+int sum(int a, int b)
+{
+  return a + b;
+}

test/as/debug/directive-file-1.c

@@ -0,0 +1,6 @@
+#include "directive-file-1-sum.c"
+
+int f(int a, int b)
+{
+  return sum(a, b);
+}

test/as/debug/directive-file-1.o.golden

@@ -0,0 +1,49 @@
+//     $ [nvptx-none-gcc] directive-file-1.c -o directive-file-1.s -S -g
+//     $ [nvptx-none-as] directive-file-1.s -o directive-file-1.o.golden
+// BEGIN PREAMBLE
+.version 3.1
+.target sm_30
+.address_size 64
+// END PREAMBLE
+// BEGIN GLOBAL FUNCTION DECL: f
+.visible .func (.param .u32 %value_out) f (.param .u32 %in_ar0, .param .u32 %in_ar1);
+.file 1 "directive-file-1-sum.c"
+.file 2 "directive-file-1.c"
+// BEGIN GLOBAL FUNCTION DEF: f
+.visible .func (.param .u32 %value_out) f (.param .u32 %in_ar0, .param .u32 %in_ar1)
+{
+.reg .u32 %value;
+.reg .u32 %ar0;
+ld.param.u32 %ar0,[%in_ar0];
+.reg .u32 %ar1;
+ld.param.u32 %ar1,[%in_ar1];
+.local .align 16 .b8 %frame_ar[24];
+.reg .u64 %frame;
+cvta.local.u64 %frame,%frame_ar;
+.reg .u32 %r22;
+.reg .u32 %r23;
+.reg .u32 %r24;
+.reg .u32 %r25;
+.reg .u32 %r26;
+.reg .u32 %r27;
+.reg .u32 %r28;
+.reg .u32 %r29;
+mov.u32 %r24,%ar0;
+st.u32 [%frame+16],%r24;
+mov.u32 %r25,%ar1;
+st.u32 [%frame+20],%r25;
+ld.u32 %r26,[%frame+16];
+st.u32 [%frame],%r26;
+ld.u32 %r27,[%frame+20];
+st.u32 [%frame+4],%r27;
+.loc 1 4 12
+ld.u32 %r28,[%frame];
+ld.u32 %r29,[%frame+4];
+add.u32 %r22,%r28,%r29;
+.loc 2 5 10
+mov.u32 %r23,%r22;
+.loc 2 6 1
+mov.u32 %value,%r23;
+st.param.u32 [%value_out],%value;
+ret;
+}

test/as/debug/directive-file-1.s

@@ -0,0 +1,54 @@
+//     $ [nvptx-none-gcc] directive-file-1.c -o directive-file-1.s -S -g
+//     $ [nvptx-none-as] directive-file-1.s -o directive-file-1.o.golden
+
+
+// BEGIN PREAMBLE
+	.version	3.1
+	.target	sm_30
+	.address_size 64
+// END PREAMBLE
+
+
+// BEGIN GLOBAL FUNCTION DECL: f
+.visible .func (.param.u32 %value_out) f (.param.u32 %in_ar0, .param.u32 %in_ar1);
+
+// BEGIN GLOBAL FUNCTION DEF: f
+.visible .func (.param.u32 %value_out) f (.param.u32 %in_ar0, .param.u32 %in_ar1)
+{
+	.reg.u32 %value;
+	.reg.u32 %ar0;
+	ld.param.u32 %ar0, [%in_ar0];
+	.reg.u32 %ar1;
+	ld.param.u32 %ar1, [%in_ar1];
+	.local .align 16 .b8 %frame_ar[24];
+	.reg.u64 %frame;
+	cvta.local.u64 %frame, %frame_ar;
+	.reg.u32 %r22;
+	.reg.u32 %r23;
+	.reg.u32 %r24;
+	.reg.u32 %r25;
+	.reg.u32 %r26;
+	.reg.u32 %r27;
+	.reg.u32 %r28;
+	.reg.u32 %r29;
+		mov.u32	%r24, %ar0;
+		st.u32	[%frame+16], %r24;
+		mov.u32	%r25, %ar1;
+		st.u32	[%frame+20], %r25;
+		ld.u32	%r26, [%frame+16];
+		st.u32	[%frame], %r26;
+		ld.u32	%r27, [%frame+20];
+		st.u32	[%frame+4], %r27;
+	.file 1 "directive-file-1-sum.c"
+	.loc 1 4 12
+		ld.u32	%r28, [%frame];
+		ld.u32	%r29, [%frame+4];
+		add.u32	%r22, %r28, %r29;
+	.file 2 "directive-file-1.c"
+	.loc 2 5 10
+		mov.u32	%r23, %r22;
+	.loc 2 6 1
+		mov.u32	%value, %r23;
+	st.param.u32	[%value_out], %value;
+	ret;
+}

test/as/debug/directive-file-1.test

@@ -0,0 +1,9 @@
+<https://github.com/MentorEmbedded/nvptx-tools/issues/20> 'nvptx-as reorders ".file" directives'
+
+In the file produced by GCC, expect 'nvptx-none-as' to reorder '.file' directives:
+RUN: %target_as_cmd --no-verify %S/directive-file-1.s -o %t
+RUN: cmp %S/directive-file-1.o.golden %t
+
+... but expect further 'nvptx-none-as' runs to be idempotent:
+RUN: %target_as_cmd --no-verify %S/directive-file-1.o.golden -o %t
+RUN: cmp %S/directive-file-1.o.golden %t