[nasm:nasm-2.15.xx] dwarf: don't emit a dummy .debug_loc section

[nasm-bot for H. Peter Anvin (Intel)]

Commit-ID:  eb571a3ac387a721d52fdab448da7c8768bdaa18
Gitweb:     http://repo.or.cz/w/nasm.git?a=commitdiff;h=eb571a3ac387a721d52fdab448da7c8768bdaa18
Author:     H. Peter Anvin (Intel) <hpa at zytor.com>
AuthorDate: Fri, 26 Jun 2020 15:22:26 -0700
Committer:  H. Peter Anvin (Intel) <hpa at zytor.com>
CommitDate: Fri, 26 Jun 2020 15:22:26 -0700

dwarf: don't emit a dummy .debug_loc section

It seems DWARF parsers get really snippy about a section which only
contains an end token. Instead, leave unused sections empty. Already
did that with .debug_frame, do it with .debug_loc too.

Signed-off-by: H. Peter Anvin (Intel) <hpa at zytor.com>


---
 output/outelf.c | 30 ++++++++++++++++--------------
 1 file changed, 16 insertions(+), 14 deletions(-)

diff --git a/output/outelf.c b/output/outelf.c
index 8af0f120..911a8529 100644
--- a/output/outelf.c
+++ b/output/outelf.c
@@ -3438,29 +3438,31 @@ static void dwarf_generate(void)
     saa_rnbytes(plinesrel, pbuf, saalen);
     saa_free(plinesrel);
 
-    /* build frame section */
+    /* build .debug_frame section */
     if (0) {
-        /* This only applies if there is at least one frame defined */
         framelen = 4;
         framebuf = pbuf = nasm_malloc(framelen);
         WRITELONG(pbuf,framelen-4); /* initial length */
     } else {
+        /* Leave .debug_frame empty if not used! */
         framelen = 0;
     }
 
-    /* build loc section */
-    loclen = 16;
-    locbuf = pbuf = nasm_malloc(loclen);
-    if (is_elf32()) {
-        WRITELONG(pbuf,0);  /* null  beginning offset */
-        WRITELONG(pbuf,0);  /* null  ending offset */
-    } else if (is_elfx32()) {
-        WRITELONG(pbuf,0);  /* null  beginning offset */
-        WRITELONG(pbuf,0);  /* null  ending offset */
+    /* build .debug_loc section */
+    if (0) {
+        loclen = 16;
+        locbuf = pbuf = nasm_malloc(loclen);
+        if (is_elf32() || is_elfx32()) {
+            WRITELONG(pbuf,0);  /* null  beginning offset */
+            WRITELONG(pbuf,0);  /* null  ending offset */
+        } else {
+            nasm_assert(is_elf64());
+            WRITEDLONG(pbuf,0);  /* null  beginning offset */
+            WRITEDLONG(pbuf,0);  /* null  ending offset */
+        }
     } else {
-        nasm_assert(is_elf64());
-        WRITEDLONG(pbuf,0);  /* null  beginning offset */
-        WRITEDLONG(pbuf,0);  /* null  ending offset */
+        /* Leave .debug_frame empty if not used! */
+        loclen = 0;
     }
 }