Create a source file a.c with the following content:
void b();
#pragma CODE_SECTION(a, ".a")
void a() {volatile int a = 0; b();}
#pragma CODE_SECTION(b, ".b")
void b() {volatile int b = 0; a();}
void c_int00(int x)
{
switch (x)
{
case 3: case 7: case 11: case 17: case 19:
case 23: case 29: case 31: case 37: case 41:
case 47: case 53: case 59: case 61: case 67:
case 71: case 73: case 79: case 83: case 89:
case 101: case 103: case 109: case 113: case 127:
case 131: case 137: case 139: case 149: case 151:
a(); break;
case 307: case 311: case 317: case 331: case 337:
case 347: case 349: case 353: case 359: case 367:
case 373: case 379: case 383: case 389: case 397:
case 401: case 409: case 419: case 421: case 431:
case 433: case 439: case 449: case 457: case 461:
case 463: case 467: case 479: case 487: case 491:
b(); break;
}
}
Create a linker command file a.cmd with the following content:
MEMORY
{
RAM: o = 0x80000000 l = 0x10000
DDR: o = 0xc0000000 l = 0x10000
}
SECTIONS
{
.a: load >> RAM
.switch: load >> DDR
.b: load >> DDR
.text: load >> DDR
}
Invoke the C6000 compiler version 7.3.1 as follows:
cl6x -mv6400+ --symdebug:none -o a.c -z -ma.map a.cmd
Now, the map file produced looks as follows:
output attributes/
section page origin length input sections
-------- ---- ---------- ---------- ----------------
.a 0 80000000 00000040
80000000 00000020 a.obj (.a)
80000020 00000010 a.obj ($Tramp$S$$_b)
80000030 00000010 --HOLE-- [fill = 0]
.text 0 c0000000 00000580
c0000000 00000560 a.obj (.text)
c0000560 00000010 a.obj ($Tramp$S$$_a)
c0000570 00000010 --HOLE-- [fill = 0]
.b 0 c0000580 00000040
c0000580 00000020 a.obj (.b)
c00005a0 00000010 a.obj ($Tramp$S$$_a)
c00005b0 00000010 --HOLE-- [fill = 0]
.switch 0 c00005b0 0000002c
c00005b0 0000002c a.obj (.switch:_c_int00)
It can be seen that section .b overlaps section .switch. This behavior is wrong for the linker, whose manual says that output sections do not overlap.
Moreover, the OFD dump of the produced a.out file shows:
id name load addr run addr size align alloc
-- ---- --------- -------- ---- ----- -----
1 $build.attributes 0x00000000 0x00000000 0x27 1 N
2 .a 0x80000000 0x80000000 0x40 32 Y
3 .switch 0xc00005b0 0xc00005b0 0x2c 4 Y
4 .b 0xc0000580 0xc0000580 0x40 32 Y
5 .text 0xc0000000 0xc0000000 0x580 32 Y
The section .switch precedes the section .b. A program loader that processes section sequentially would load section .switch first, and then section.b. As a result section .b would destroy the first 16 bytes of section .switch.
The above indeeds happens when the file a.out is loaded onto a target or simulator memory via Code Composer Stdio.
This bug appears in cgtools 7.3.1. It did not manifest in earlier tools, because the trampolines generates were 32 bytes long.
In addition, the bug appears only when the automatic section split operator '>>' is used in the command file. The regular operator '>' or '=' produces a correct output file.
The problem is that the RTSC/XDC tools generate linker command files that use the '>>' operator, and the described bug manifests itself.
