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.
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@ -1,3 +1,10 @@
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2015-01-20 Andrew Burgess <andrew.burgess@embecosm.com>
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* ldlang.c (print_assignment): Only evaluate the expression for a
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PROVIDE'd assignment when the destination is being defined.
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Display a special message for PROVIDE'd symbols that are not being
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provided.
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2015-01-20 Alan Modra <amodra@gmail.com>
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* emulparams/elf64ppc.sh (BSS_PLT): Don't define.
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12
ld/ldlang.c
12
ld/ldlang.c
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@ -3983,7 +3983,12 @@ print_assignment (lang_assignment_statement_type *assignment,
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osec = output_section->bfd_section;
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if (osec == NULL)
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osec = bfd_abs_section_ptr;
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exp_fold_tree (tree, osec, &print_dot);
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if (assignment->exp->type.node_class != etree_provide)
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exp_fold_tree (tree, osec, &print_dot);
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else
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expld.result.valid_p = FALSE;
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if (expld.result.valid_p)
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{
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bfd_vma value;
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@ -4021,7 +4026,10 @@ print_assignment (lang_assignment_statement_type *assignment,
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}
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else
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{
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minfo ("*undef* ");
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if (assignment->exp->type.node_class == etree_provide)
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minfo ("[!provide]");
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else
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minfo ("*undef* ");
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#ifdef BFD64
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minfo (" ");
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#endif
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@ -1,3 +1,15 @@
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2015-01-20 Andrew Burgess <andrew.burgess@embecosm.com>
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* ld-scripts/provide-4.d: New file.
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* ld-scripts/provide-4-map.d: New file.
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* ld-scripts/provide-4.t: New file.
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* ld-scripts/provide-5.d: New file.
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* ld-scripts/provide-5.s: New file.
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* ld-scripts/provide-5-map.d: New file.
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* ld-scripts/provide-5.t: New file.
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* ld-scripts/provide.exp: Run the provide-4.d and provide-5.d
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tests.
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2015-01-20 Andrew Burgess <andrew.burgess@embecosm.com>
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* ld-scripts/overlay-size.d: Add 'map' option.
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@ -0,0 +1,13 @@
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#...
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Linker script and memory map
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#...
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\[!provide\] PROVIDE \(foo, 0x1\)
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\[!provide\] PROVIDE \(bar, 0x2\)
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0x0+3 PROVIDE \(baz, 0x3\)
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#...
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0x0+2000 foo
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\[!provide\] PROVIDE \(loc1, ALIGN \(\., 0x10\)\)
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0x0+2010 PROVIDE \(loc2, ALIGN \(\., 0x10\)\)
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\[!provide\] PROVIDE \(loc3, \(loc1 \+ 0x20\)\)
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0x0+2030 loc4 = \(loc2 \+ 0x20\)
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#...
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@ -0,0 +1,9 @@
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#source: provide-2.s
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#ld: -T provide-4.t
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#PROG: nm
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#map: provide-4-map.d
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#...
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0+3 A baz
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0+2000 D foo
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0+2010 D loc2
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0+2030 A loc4
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@ -0,0 +1,16 @@
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SECTIONS
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{
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PROVIDE (foo = 1);
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PROVIDE (bar = 2);
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PROVIDE (baz = 3);
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.data 0x2000 :
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{
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*(.data)
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PROVIDE (loc1 = ALIGN (., 0x10));
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PROVIDE (loc2 = ALIGN (., 0x10));
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}
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PROVIDE (loc3 = loc1 + 0x20);
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loc4 = loc2 + 0x20;
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}
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@ -0,0 +1,6 @@
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#...
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Linker script and memory map
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#...
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0x0+10 foo = 0x10
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\[!provide\] PROVIDE \(foo, bar\)
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#...
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@ -0,0 +1,6 @@
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#source: provide-5.s
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#ld: -T provide-5.t
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#PROG: nm
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#map: provide-5-map.d
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#...
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0+10 A foo
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@ -0,0 +1,4 @@
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.data
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.global baz
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baz:
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.word 0
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@ -0,0 +1,10 @@
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SECTIONS
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{
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foo = 0x10;
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PROVIDE (foo = bar);
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.data 0x1000 :
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{
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*(.data)
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}
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}
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@ -40,5 +40,7 @@ run_dump_test provide-1
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run_dump_test provide-2
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setup_xfail *-*-*
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run_dump_test provide-3
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run_dump_test provide-4
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run_dump_test provide-5
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set LDFLAGS "$saved_LDFLAGS"
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