[PATCH 09/48] perf dwarf-regs: Add get_dwarf_regnum()

From: Namhyung Kim
Date: Wed Oct 11 2023 - 23:52:18 EST


The get_dwarf_regnum() returns a DWARF register number from a register
name string according to the psABI. Also add two pseudo encodings of
DWARF_REG_PC which is a register that are used by PC-relative addressing
and DWARF_REG_FB which is a frame base register. They need to be
handled in a special way.

Cc: Masami Hiramatsu <mhiramat@xxxxxxxxxx>
Signed-off-by: Namhyung Kim <namhyung@xxxxxxxxxx>
---
tools/perf/arch/x86/util/dwarf-regs.c | 38 +++++++++++++++++++++++++++
tools/perf/util/dwarf-regs.c | 33 +++++++++++++++++++++++
tools/perf/util/include/dwarf-regs.h | 11 ++++++++
3 files changed, 82 insertions(+)

diff --git a/tools/perf/arch/x86/util/dwarf-regs.c b/tools/perf/arch/x86/util/dwarf-regs.c
index 530934805710..79835b897cae 100644
--- a/tools/perf/arch/x86/util/dwarf-regs.c
+++ b/tools/perf/arch/x86/util/dwarf-regs.c
@@ -113,3 +113,41 @@ int regs_query_register_offset(const char *name)
return roff->offset;
return -EINVAL;
}
+
+struct dwarf_regs_idx {
+ const char *name;
+ int idx;
+};
+
+static const struct dwarf_regs_idx x86_regidx_table[] = {
+ { "rax", 0 }, { "eax", 0 }, { "ax", 0 }, { "al", 0 },
+ { "rdx", 1 }, { "edx", 1 }, { "dx", 1 }, { "dl", 1 },
+ { "rcx", 2 }, { "ecx", 2 }, { "cx", 2 }, { "cl", 2 },
+ { "rbx", 3 }, { "edx", 3 }, { "bx", 3 }, { "bl", 3 },
+ { "rsi", 4 }, { "esi", 4 }, { "si", 4 }, { "sil", 4 },
+ { "rdi", 5 }, { "edi", 5 }, { "di", 5 }, { "dil", 5 },
+ { "rbp", 6 }, { "ebp", 6 }, { "bp", 6 }, { "bpl", 6 },
+ { "rsp", 7 }, { "esp", 7 }, { "sp", 7 }, { "spl", 7 },
+ { "r8", 8 }, { "r8d", 8 }, { "r8w", 8 }, { "r8b", 8 },
+ { "r9", 9 }, { "r9d", 9 }, { "r9w", 9 }, { "r9b", 9 },
+ { "r10", 10 }, { "r10d", 10 }, { "r10w", 10 }, { "r10b", 10 },
+ { "r11", 11 }, { "r11d", 11 }, { "r11w", 11 }, { "r11b", 11 },
+ { "r12", 12 }, { "r12d", 12 }, { "r12w", 12 }, { "r12b", 12 },
+ { "r13", 13 }, { "r13d", 13 }, { "r13w", 13 }, { "r13b", 13 },
+ { "r14", 14 }, { "r14d", 14 }, { "r14w", 14 }, { "r14b", 14 },
+ { "r15", 15 }, { "r15d", 15 }, { "r15w", 15 }, { "r15b", 15 },
+ { "rip", DWARF_REG_PC },
+};
+
+int get_arch_regnum(const char *name)
+{
+ unsigned int i;
+
+ if (*name != '%')
+ return -1;
+
+ for (i = 0; i < ARRAY_SIZE(x86_regidx_table); i++)
+ if (!strcmp(x86_regidx_table[i].name, name + 1))
+ return x86_regidx_table[i].idx;
+ return -1;
+}
diff --git a/tools/perf/util/dwarf-regs.c b/tools/perf/util/dwarf-regs.c
index 69cfaa5953bf..28d786c7df55 100644
--- a/tools/perf/util/dwarf-regs.c
+++ b/tools/perf/util/dwarf-regs.c
@@ -5,6 +5,8 @@
* Written by: Masami Hiramatsu <mhiramat@xxxxxxxxxx>
*/

+#include <stdlib.h>
+#include <string.h>
#include <debug.h>
#include <dwarf-regs.h>
#include <elf.h>
@@ -68,3 +70,34 @@ const char *get_dwarf_regstr(unsigned int n, unsigned int machine)
}
return NULL;
}
+
+__weak int get_arch_regnum(const char *name __maybe_unused)
+{
+ return -1;
+}
+
+/* Return DWARF register number from architecture register name */
+int get_dwarf_regnum(const char *name, unsigned int machine)
+{
+ char *regname = strdup(name);
+ int reg = -1;
+ char *p;
+
+ if (regname == NULL)
+ return -1;
+
+ /* For convenience, remove trailing characters */
+ p = strpbrk(regname, " ,)");
+ if (p)
+ *p = '\0';
+
+ switch (machine) {
+ case EM_NONE: /* Generic arch - use host arch */
+ reg = get_arch_regnum(regname);
+ break;
+ default:
+ pr_err("ELF MACHINE %x is not supported.\n", machine);
+ }
+ free(regname);
+ return reg;
+}
diff --git a/tools/perf/util/include/dwarf-regs.h b/tools/perf/util/include/dwarf-regs.h
index 7d99a084e82d..b515f694f55e 100644
--- a/tools/perf/util/include/dwarf-regs.h
+++ b/tools/perf/util/include/dwarf-regs.h
@@ -2,6 +2,9 @@
#ifndef _PERF_DWARF_REGS_H_
#define _PERF_DWARF_REGS_H_

+#define DWARF_REG_PC 0xd3af9c /* random number */
+#define DWARF_REG_FB 0xd3affb /* random number */
+
#ifdef HAVE_DWARF_SUPPORT
const char *get_arch_regstr(unsigned int n);
/*
@@ -10,6 +13,14 @@ const char *get_arch_regstr(unsigned int n);
* machine: ELF machine signature (EM_*)
*/
const char *get_dwarf_regstr(unsigned int n, unsigned int machine);
+
+int get_arch_regnum(const char *name);
+/*
+ * get_dwarf_regnum - Returns DWARF regnum from register name
+ * name: architecture register name
+ * machine: ELF machine signature (EM_*)
+ */
+int get_dwarf_regnum(const char *name, unsigned int machine);
#endif

#ifdef HAVE_ARCH_REGS_QUERY_REGISTER_OFFSET
--
2.42.0.655.g421f12c284-goog