svn commit: r238593 - vendor/illumos/dist/tools/ctf/cvt

[Martin Matuska]

Author: mm
Date: Wed Jul 18 10:58:30 2012
New Revision: 238593
URL: http://svn.freebsd.org/changeset/base/238593

Log:
  Update vendor-sys/illumos/dist to illumos-gate 13752:9f5f6c52ba19
  (non-zfs part)
  
  Obtained from:	ssh://anonhg@hg.illumos.org/illumos-gate

Modified:
  vendor/illumos/dist/tools/ctf/cvt/dwarf.c

Modified: vendor/illumos/dist/tools/ctf/cvt/dwarf.c
==============================================================================
--- vendor/illumos/dist/tools/ctf/cvt/dwarf.c	Wed Jul 18 10:58:07 2012	(r238592)
+++ vendor/illumos/dist/tools/ctf/cvt/dwarf.c	Wed Jul 18 10:58:30 2012	(r238593)
@@ -22,6 +22,10 @@
  * Copyright 2007 Sun Microsystems, Inc.  All rights reserved.
  * Use is subject to license terms.
  */
+/*
+ * Copyright 2012 Jason King.  All rights reserved.
+ * Use is subject to license terms.
+ */
 
 /*
  * DWARF to tdata conversion
@@ -360,6 +364,37 @@ die_attr_form(dwarf_t *dw, Dwarf_Attribu
 	return (0);
 }
 
+/*
+ * the following functions lookup the value of an attribute in a DIE:
+ *
+ * die_signed
+ * die_unsigned
+ * die_bool
+ * die_string
+ *
+ * They all take the same parameters (with the exception of valp which is
+ * a pointer to the type of the attribute we are looking up):
+ *
+ * dw - the dwarf object to look in
+ * die - the DIE we're interested in
+ * name - the name of the attribute to lookup
+ * valp - pointer to where the value of the attribute is placed
+ * req - if the value is required (0 / non-zero)
+ *
+ * If the attribute is not found, one of the following happens:
+ * - program terminates (req is non-zero)
+ * - function returns 0
+ *
+ * If the value is found, and in a form (class) we can handle, the function
+ * returns 1.
+ *
+ * Currently, we can only handle attribute values that are stored as
+ * constants (immediate value).  If an attribute has a form we cannot
+ * handle (for example VLAs may store the dimensions of the array
+ * as a DWARF expression that can compute it at runtime by reading
+ * values off the stack or other locations in memory), it is treated
+ * the same as if the attribute does not exist.
+ */
 static int
 die_signed(dwarf_t *dw, Dwarf_Die die, Dwarf_Half name, Dwarf_Signed *valp,
     int req)
@@ -371,6 +406,9 @@ die_signed(dwarf_t *dw, Dwarf_Die die, D
 		return (0); /* die_attr will terminate for us if necessary */
 
 	if (dwarf_formsdata(attr, &val, &dw->dw_err) != DW_DLV_OK) {
+		if (req == 0)
+			return (0);
+
 		terminate("die %llu: failed to get signed (form 0x%x)\n",
 		    die_off(dw, die), die_attr_form(dw, attr));
 	}
@@ -392,6 +430,9 @@ die_unsigned(dwarf_t *dw, Dwarf_Die die,
 		return (0); /* die_attr will terminate for us if necessary */
 
 	if (dwarf_formudata(attr, &val, &dw->dw_err) != DW_DLV_OK) {
+		if (req == 0)
+			return (0);
+
 		terminate("die %llu: failed to get unsigned (form 0x%x)\n",
 		    die_off(dw, die), die_attr_form(dw, attr));
 	}
@@ -412,6 +453,9 @@ die_bool(dwarf_t *dw, Dwarf_Die die, Dwa
 		return (0); /* die_attr will terminate for us if necessary */
 
 	if (dwarf_formflag(attr, &val, &dw->dw_err) != DW_DLV_OK) {
+		if (req == 0)
+			return (0);
+
 		terminate("die %llu: failed to get bool (form 0x%x)\n",
 		    die_off(dw, die), die_attr_form(dw, attr));
 	}
@@ -432,6 +476,9 @@ die_string(dwarf_t *dw, Dwarf_Die die, D
 		return (0); /* die_attr will terminate for us if necessary */
 
 	if (dwarf_formstring(attr, &str, &dw->dw_err) != DW_DLV_OK) {
+		if (req == 0)
+			return (0);
+
 		terminate("die %llu: failed to get string (form 0x%x)\n",
 		    die_off(dw, die), die_attr_form(dw, attr));
 	}
@@ -1791,6 +1838,27 @@ die_resolve(dwarf_t *dw)
 	} while (dw->dw_nunres != 0);
 }
 
+/*
+ * Any object containing at least one allocatable section of non-0 size is
+ * taken to be a file which should contain DWARF type information
+ */
+static boolean_t
+should_have_dwarf(Elf *elf)
+{
+	Elf_Scn *scn = NULL;
+
+	while ((scn = elf_nextscn(elf, scn)) != NULL) {
+		GElf_Shdr shdr;
+		gelf_getshdr(scn, &shdr);
+
+		if ((shdr.sh_flags & SHF_ALLOC) &&
+		    (shdr.sh_size != 0))
+			return (B_TRUE);
+	}
+
+	return (B_FALSE);
+}
+
 /*ARGSUSED*/
 int
 dw_read(tdata_t *td, Elf *elf, const char *filename)
@@ -1814,8 +1882,12 @@ dw_read(tdata_t *td, Elf *elf, const cha
 
 	if ((rc = dwarf_elf_init(elf, DW_DLC_READ, NULL, NULL, &dw.dw_dw,
 	    &dw.dw_err)) == DW_DLV_NO_ENTRY) {
-		errno = ENOENT;
-		return (-1);
+		if (should_have_dwarf(elf)) {
+			errno = ENOENT;
+			return (-1);
+		} else {
+			return (0);
+		}
 	} else if (rc != DW_DLV_OK) {
 		if (dwarf_errno(dw.dw_err) == DW_DLE_DEBUG_INFO_NULL) {
 			/*
@@ -1834,10 +1906,18 @@ dw_read(tdata_t *td, Elf *elf, const cha
 		terminate("file does not contain valid DWARF data: %s\n",
 		    dwarf_errmsg(dw.dw_err));
 
+	/*
+	 * Some compilers emit no DWARF for empty files, others emit an empty
+	 * compilation unit.
+	 */
 	if ((cu = die_sibling(&dw, NULL)) == NULL ||
-	    (child = die_child(&dw, cu)) == NULL)
+	    ((child = die_child(&dw, cu)) == NULL) &&
+	    should_have_dwarf(elf)) {
 		terminate("file does not contain dwarf type data "
 		    "(try compiling with -g)\n");
+	} else if (child == NULL) {
+		return (0);
+	}
 
 	dw.dw_maxoff = nxthdr - 1;