124 lines
4.2 KiB
Diff
124 lines
4.2 KiB
Diff
From f0416e6a2af1fb1f2b18a4410e679f25c57c5e9f Mon Sep 17 00:00:00 2001
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From: Xi Ruoyao <xry111@xry111.site>
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Date: Thu, 11 Jul 2024 19:43:48 +0800
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Subject: [PATCH 19/20] LoongArch: Add support to annotate tablejump
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This is per the request from the kernel developers. For generating the
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ORC unwind info, the objtool program needs to analysis the control flow
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of a .o file. If a jump table is used, objtool has to correlate the
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jump instruction with the table.
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On x86 (where objtool was initially developed) it's simple: a relocation
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entry natrually correlates them because one single instruction is used
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for table-based jump. But on an RISC machine objtool would have to
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reconstruct the data flow if it must find out the correlation on its
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own.
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So, emit an additional section to store the correlation info as pairs of
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addresses, each pair contains the address of a jump instruction (jr) and
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the address of the jump table. This is very trivial to implement in
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GCC.
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gcc/ChangeLog:
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* config/loongarch/genopts/loongarch.opt.in
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(mannotate-tablejump): New option.
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* config/loongarch/loongarch.opt: Regenerate.
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* config/loongarch/loongarch.md (tablejump<mode>): Emit
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additional correlation info between the jump instruction and the
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jump table, if -mannotate-tablejump.
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* doc/invoke.texi: Document -mannotate-tablejump.
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gcc/testsuite/ChangeLog:
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* gcc.target/loongarch/jump-table-annotate.c: New test.
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Suggested-by: Tiezhu Yang <yangtiezhu@loongson.cn>
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---
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gcc/config/loongarch/genopts/loongarch.opt.in | 4 ++++
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gcc/config/loongarch/loongarch.md | 12 +++++++++++-
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gcc/config/loongarch/loongarch.opt | 4 ++++
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.../gcc.target/loongarch/jump-table-annotate.c | 15 +++++++++++++++
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4 files changed, 34 insertions(+), 1 deletion(-)
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create mode 100644 gcc/testsuite/gcc.target/loongarch/jump-table-annotate.c
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diff --git a/gcc/config/loongarch/genopts/loongarch.opt.in b/gcc/config/loongarch/genopts/loongarch.opt.in
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index d00950cb4..d5bbf01d8 100644
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--- a/gcc/config/loongarch/genopts/loongarch.opt.in
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+++ b/gcc/config/loongarch/genopts/loongarch.opt.in
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@@ -301,3 +301,7 @@ default value is 4.
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; CPUCFG independently, so we use bit flags to specify them.
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TargetVariable
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HOST_WIDE_INT la_isa_evolution = 0
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+
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+mannotate-tablejump
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+Target Mask(ANNOTATE_TABLEJUMP) Save
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+Annotate table jump instruction (jr {reg}) to correlate it with the jump table.
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diff --git a/gcc/config/loongarch/loongarch.md b/gcc/config/loongarch/loongarch.md
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index f70ca85bf..bd0825002 100644
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--- a/gcc/config/loongarch/loongarch.md
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+++ b/gcc/config/loongarch/loongarch.md
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@@ -3496,12 +3496,22 @@
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DONE;
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})
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+(define_mode_attr mode_size [(DI "8") (SI "4")])
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+
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(define_insn "@tablejump<mode>"
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[(set (pc)
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(match_operand:P 0 "register_operand" "e"))
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(use (label_ref (match_operand 1 "" "")))]
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""
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- "jr\t%0"
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+ {
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+ return TARGET_ANNOTATE_TABLEJUMP
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+ ? "1:jr\t%0\n\t"
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+ ".pushsection\t.discard.tablejump_annotate\n\t"
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+ "\t.<mode_size>byte\t1b\n\t"
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+ "\t.<mode_size>byte\t%1\n\t"
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+ ".popsection"
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+ : "jr\t%0";
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+ }
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[(set_attr "type" "jump")
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(set_attr "mode" "none")])
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diff --git a/gcc/config/loongarch/loongarch.opt b/gcc/config/loongarch/loongarch.opt
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index 91cb5236a..6a396b539 100644
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--- a/gcc/config/loongarch/loongarch.opt
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+++ b/gcc/config/loongarch/loongarch.opt
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@@ -310,6 +310,10 @@ default value is 4.
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TargetVariable
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HOST_WIDE_INT la_isa_evolution = 0
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+mannotate-tablejump
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+Target Mask(ANNOTATE_TABLEJUMP) Save
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+Annotate table jump instruction (jr {reg}) to correlate it with the jump table
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+
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mfrecipe
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Target Mask(ISA_FRECIPE) Var(la_isa_evolution)
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Support frecipe.{s/d} and frsqrte.{s/d} instructions.
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diff --git a/gcc/testsuite/gcc.target/loongarch/jump-table-annotate.c b/gcc/testsuite/gcc.target/loongarch/jump-table-annotate.c
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new file mode 100644
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index 000000000..9d58e60e3
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--- /dev/null
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+++ b/gcc/testsuite/gcc.target/loongarch/jump-table-annotate.c
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@@ -0,0 +1,15 @@
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+/* { dg-do compile } */
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+/* { dg-additional-options "-mannotate-tablejump" } */
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+
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+extern void asdf(int);
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+void foo(int x) {
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+ switch (x) {
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+ case 0: asdf(10); break;
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+ case 1: asdf(11); break;
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+ case 2: asdf(12); break;
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+ case 3: asdf(13); break;
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+ case 4: asdf(14); break;
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+ }
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+}
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+
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+/* { dg-final { scan-assembler "\\.discard\\.tablejump_annotate" } } */
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--
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2.43.0
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