[binutils-gdb/binutils-2_25-branch] ld: Don't evaluate unneeded PROVIDE expressions.
Alan Modra
amodra@sourceware.org
Wed Feb 11 12:54:00 GMT 2015
https://sourceware.org/git/gitweb.cgi?p=binutils-gdb.git;h=9320edc3f859dbe66c7786058ab89833b0fce346
commit 9320edc3f859dbe66c7786058ab89833b0fce346
Author: Andrew Burgess <andrew.burgess@embecosm.com>
Date: Wed Jan 7 10:51:35 2015 +0000
ld: Don't evaluate unneeded PROVIDE expressions.
When creating a linker mapfile (using -Map=MAPFILE), we previously would
always try to evaluate the expression from a PROVIDE statement.
However, this is not always safe, consider:
PROVIDE (foo = 0x10);
PROVIDE (bar = foo);
In this example, if neither 'foo' or 'bar' is needed, then while
generating the linker mapfile evaluating the expression for 'foo' is
harmless (just the value 0x10). However, evaluating the expression for
'bar' requires the symbol 'foo', which is undefined. This used to cause
a fatal error.
This patch changes the behaviour, so that when the destination of the
PROVIDE is not defined (that is the PROVIDE is not going to provide
anything) the expression is not evaluated, and instead a special string
is displayed to indicate that the linker is discarding the PROVIDE
statement.
This change not only fixes the spurious undefined symbol error, but also
means that a user can now tell if a PROVIDE statement has provided
anything by inspecting the linker mapfile, something that could not be
done before.
ld/ChangeLog:
* ldlang.c (print_assignment): Only evaluate the expression for a
PROVIDE'd assignment when the destination is being defined.
Display a special message for PROVIDE'd symbols that are not being
provided.
ld/testsuite/ChangeLog:
* ld-scripts/provide-4.d: New file.
* ld-scripts/provide-4-map.d: New file.
* ld-scripts/provide-4.t: New file.
* ld-scripts/provide-5.d: New file.
* ld-scripts/provide-5.s: New file.
* ld-scripts/provide-5-map.d: New file.
* ld-scripts/provide-5.t: New file.
* ld-scripts/provide.exp: Run the provide-4.d and provide-5.d
tests.
Diff:
---
ld/ChangeLog | 6 ++++++
ld/ldlang.c | 12 ++++++++++--
ld/testsuite/ChangeLog | 11 +++++++++++
ld/testsuite/ld-scripts/provide-4-map.d | 13 +++++++++++++
ld/testsuite/ld-scripts/provide-4.d | 9 +++++++++
ld/testsuite/ld-scripts/provide-4.t | 16 ++++++++++++++++
ld/testsuite/ld-scripts/provide-5-map.d | 6 ++++++
ld/testsuite/ld-scripts/provide-5.d | 6 ++++++
ld/testsuite/ld-scripts/provide-5.s | 4 ++++
ld/testsuite/ld-scripts/provide-5.t | 10 ++++++++++
ld/testsuite/ld-scripts/provide.exp | 2 ++
11 files changed, 93 insertions(+), 2 deletions(-)
diff --git a/ld/ChangeLog b/ld/ChangeLog
index 594fc28..1f34f5e 100644
--- a/ld/ChangeLog
+++ b/ld/ChangeLog
@@ -1,6 +1,12 @@
2015-02-11 Alan Modra <amodra@gmail.com>
Apply from master.
+ 2015-01-20 Andrew Burgess <andrew.burgess@embecosm.com>
+ * ldlang.c (print_assignment): Only evaluate the expression for a
+ PROVIDE'd assignment when the destination is being defined.
+ Display a special message for PROVIDE'd symbols that are not being
+ provided.
+
2015-01-19 Alan Modra <amodra@gmail.com>
PR 17165
* ldlang.c (lang_process): Run lang_common before lang_gc_sections.
diff --git a/ld/ldlang.c b/ld/ldlang.c
index dc787b0..2433acf 100644
--- a/ld/ldlang.c
+++ b/ld/ldlang.c
@@ -3983,7 +3983,12 @@ print_assignment (lang_assignment_statement_type *assignment,
osec = output_section->bfd_section;
if (osec == NULL)
osec = bfd_abs_section_ptr;
- exp_fold_tree (tree, osec, &print_dot);
+
+ if (assignment->exp->type.node_class != etree_provide)
+ exp_fold_tree (tree, osec, &print_dot);
+ else
+ expld.result.valid_p = FALSE;
+
if (expld.result.valid_p)
{
bfd_vma value;
@@ -4021,7 +4026,10 @@ print_assignment (lang_assignment_statement_type *assignment,
}
else
{
- minfo ("*undef* ");
+ if (assignment->exp->type.node_class == etree_provide)
+ minfo ("[!provide]");
+ else
+ minfo ("*undef* ");
#ifdef BFD64
minfo (" ");
#endif
diff --git a/ld/testsuite/ChangeLog b/ld/testsuite/ChangeLog
index d7dfad8..0b97c82 100644
--- a/ld/testsuite/ChangeLog
+++ b/ld/testsuite/ChangeLog
@@ -2,6 +2,17 @@
Apply from master.
2015-01-20 Andrew Burgess <andrew.burgess@embecosm.com>
+ * ld-scripts/provide-4.d: New file.
+ * ld-scripts/provide-4-map.d: New file.
+ * ld-scripts/provide-4.t: New file.
+ * ld-scripts/provide-5.d: New file.
+ * ld-scripts/provide-5.s: New file.
+ * ld-scripts/provide-5-map.d: New file.
+ * ld-scripts/provide-5.t: New file.
+ * ld-scripts/provide.exp: Run the provide-4.d and provide-5.d
+ tests.
+
+ 2015-01-20 Andrew Burgess <andrew.burgess@embecosm.com>
* ld-scripts/overlay-size.d: Add 'map' option.
* ld-scripts/overlay-size.exp: Remove manual check of mapfile.
* lib/ld-lib.exp (run_dump_test): Add support for new 'map'
diff --git a/ld/testsuite/ld-scripts/provide-4-map.d b/ld/testsuite/ld-scripts/provide-4-map.d
new file mode 100644
index 0000000..d8e4a28
--- /dev/null
+++ b/ld/testsuite/ld-scripts/provide-4-map.d
@@ -0,0 +1,13 @@
+#...
+Linker script and memory map
+#...
+ \[!provide\] PROVIDE \(foo, 0x1\)
+ \[!provide\] PROVIDE \(bar, 0x2\)
+ 0x0+3 PROVIDE \(baz, 0x3\)
+#...
+ 0x0+2000 foo
+ \[!provide\] PROVIDE \(loc1, ALIGN \(\., 0x10\)\)
+ 0x0+2010 PROVIDE \(loc2, ALIGN \(\., 0x10\)\)
+ \[!provide\] PROVIDE \(loc3, \(loc1 \+ 0x20\)\)
+ 0x0+2030 loc4 = \(loc2 \+ 0x20\)
+#...
diff --git a/ld/testsuite/ld-scripts/provide-4.d b/ld/testsuite/ld-scripts/provide-4.d
new file mode 100644
index 0000000..a7d37e3
--- /dev/null
+++ b/ld/testsuite/ld-scripts/provide-4.d
@@ -0,0 +1,9 @@
+#source: provide-2.s
+#ld: -T provide-4.t
+#PROG: nm
+#map: provide-4-map.d
+#...
+0+3 A baz
+0+2000 D foo
+0+2010 D loc2
+0+2030 A loc4
diff --git a/ld/testsuite/ld-scripts/provide-4.t b/ld/testsuite/ld-scripts/provide-4.t
new file mode 100644
index 0000000..424c238
--- /dev/null
+++ b/ld/testsuite/ld-scripts/provide-4.t
@@ -0,0 +1,16 @@
+SECTIONS
+{
+ PROVIDE (foo = 1);
+ PROVIDE (bar = 2);
+ PROVIDE (baz = 3);
+ .data 0x2000 :
+ {
+ *(.data)
+
+ PROVIDE (loc1 = ALIGN (., 0x10));
+ PROVIDE (loc2 = ALIGN (., 0x10));
+ }
+
+ PROVIDE (loc3 = loc1 + 0x20);
+ loc4 = loc2 + 0x20;
+}
diff --git a/ld/testsuite/ld-scripts/provide-5-map.d b/ld/testsuite/ld-scripts/provide-5-map.d
new file mode 100644
index 0000000..2271dfd
--- /dev/null
+++ b/ld/testsuite/ld-scripts/provide-5-map.d
@@ -0,0 +1,6 @@
+#...
+Linker script and memory map
+#...
+ 0x0+10 foo = 0x10
+ \[!provide\] PROVIDE \(foo, bar\)
+#...
diff --git a/ld/testsuite/ld-scripts/provide-5.d b/ld/testsuite/ld-scripts/provide-5.d
new file mode 100644
index 0000000..1b14fa6
--- /dev/null
+++ b/ld/testsuite/ld-scripts/provide-5.d
@@ -0,0 +1,6 @@
+#source: provide-5.s
+#ld: -T provide-5.t
+#PROG: nm
+#map: provide-5-map.d
+#...
+0+10 A foo
diff --git a/ld/testsuite/ld-scripts/provide-5.s b/ld/testsuite/ld-scripts/provide-5.s
new file mode 100644
index 0000000..1d05efd
--- /dev/null
+++ b/ld/testsuite/ld-scripts/provide-5.s
@@ -0,0 +1,4 @@
+ .data
+ .global baz
+baz:
+ .word 0
diff --git a/ld/testsuite/ld-scripts/provide-5.t b/ld/testsuite/ld-scripts/provide-5.t
new file mode 100644
index 0000000..eda741e
--- /dev/null
+++ b/ld/testsuite/ld-scripts/provide-5.t
@@ -0,0 +1,10 @@
+SECTIONS
+{
+ foo = 0x10;
+ PROVIDE (foo = bar);
+
+ .data 0x1000 :
+ {
+ *(.data)
+ }
+}
diff --git a/ld/testsuite/ld-scripts/provide.exp b/ld/testsuite/ld-scripts/provide.exp
index a6d3514..83b5c0f 100644
--- a/ld/testsuite/ld-scripts/provide.exp
+++ b/ld/testsuite/ld-scripts/provide.exp
@@ -40,5 +40,7 @@ run_dump_test provide-1
run_dump_test provide-2
setup_xfail *-*-*
run_dump_test provide-3
+run_dump_test provide-4
+run_dump_test provide-5
set LDFLAGS "$saved_LDFLAGS"
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