hare

commit 3d39248bb3adb5421a787c1549c467e3635057af
parent e952359b927844a2176aeffb9d82adad69ba647b
Author: Mykyta Holubakha <hilobakho@gmail.com>
Date:   Sun, 25 Apr 2021 15:42:54 +0300

rt: add functions to walk stack frames

Co-authored-by: Drew DeVault <sir@cmpwn.com>
Signed-off-by: Mykyta Holubakha <hilobakho@gmail.com>
Signed-off-by: Drew DeVault <sir@cmpwn.com>

Diffstat:
A
rt/+aarch64/backtrace.ha
 | 
19
+++++++++++++++++++
A
rt/+aarch64/getfp.s
 | 
5
+++++
A
rt/+x86_64/backtrace.ha
 | 
20
++++++++++++++++++++
A
rt/+x86_64/getfp.s
 | 
5
+++++
M
scripts/gen-stdlib
 | 
7
+++++++
M
stdlib.mk
 | 
14
++++++++++++++

6 files changed, 70 insertions(+), 0 deletions(-)
diff --git a/rt/+aarch64/backtrace.ha b/rt/+aarch64/backtrace.ha
@@ -0,0 +1,19 @@
+fn getfp() **void;
+
+// Details for a stack frame. Contents are architecture-specific.
+export type frame = struct {
+	fp: nullable *frame,
+	lr: nullable *void,
+};
+
+// Returns the caller's stack frame. Call [[nextframe]] to walk the stack.
+export fn backtrace() frame = *(getfp(): *frame);
+
+// Returns the frame above the current frame, if any.
+export fn nextframe(fp: *frame) (frame | void) = {
+	return match (fp.fp) {
+		null => void,
+		fp: *frame => *fp,
+	};
+};
+
diff --git a/rt/+aarch64/getfp.s b/rt/+aarch64/getfp.s
@@ -0,0 +1,5 @@
+.global rt.getfp
+.type rt.getfp,@function
+rt.getfp:
+	mov x0, x29
+	ret
diff --git a/rt/+x86_64/backtrace.ha b/rt/+x86_64/backtrace.ha
@@ -0,0 +1,20 @@
+fn getfp() **void;
+
+// Details for a stack frame. Contents are architecture-specific.
+export type frame = struct {
+	addr: *void
+};
+
+// Returns the current stack frame. See [[nextframe]] to walk the stack.
+export fn backtrace() frame = frame {
+	addr = getfp()
+};
+
+// Returns the frame above the current frame, if any.
+export fn nextframe(sframe: frame) (frame | void) = {
+	let addr = sframe.addr: *nullable *void;
+	return match (*addr) {
+		null => void,
+		a: *void => frame { addr = a }
+	};
+};
diff --git a/rt/+x86_64/getfp.s b/rt/+x86_64/getfp.s
@@ -0,0 +1,5 @@
+.global rt.getfp
+.type rt.getfp,@function
+rt.getfp:
+	mov (%rbp),%rax
+	ret
diff --git a/scripts/gen-stdlib b/scripts/gen-stdlib
@@ -29,6 +29,7 @@ gensrcs_rt() {
 		'$(PLATFORM)/stat.ha' \
 		'$(PLATFORM)/socket.ha' \
 		'$(ARCH)/jmp.ha' \
+		'$(ARCH)/backtrace.ha' \
 		ensure.ha \
 		jmp.ha \
 		malloc.ha \
@@ -66,6 +67,7 @@ ${stdlib}_asm=\$($cache)/rt/syscall.o \\
 	\$($cache)/rt/setjmp.o \\
 	\$($cache)/rt/longjmp.o \\
 	\$($cache)/rt/restore.o \\
+	\$($cache)/rt/getfp.o \\
 	\$($cache)/rt/start.o
 
 \$($cache)/rt/syscall.o: \$(STDLIB)/rt/\$(PLATFORM)/syscall\$(ARCH).s
@@ -88,6 +90,11 @@ ${stdlib}_asm=\$($cache)/rt/syscall.o \\
 	@mkdir -p \$($cache)/rt
 	@\$(AS) -o \$@ \$<
 
+\$($cache)/rt/getfp.o: \$(STDLIB)/rt/\$(ARCH)/getfp.s
+	@printf 'AS \t\$@\n'
+	@mkdir -p \$($cache)/rt
+	@\$(AS) -o \$@ \$<
+
 \$($cache)/rt/rt.a: \$($cache)/rt/rt.o \$(${stdlib}_asm)
 	@printf 'AR\t\$@\n'
 	@\$(AR) -csr \$@ \$($cache)/rt/rt.o \$(${stdlib}_asm)
diff --git a/stdlib.mk b/stdlib.mk
@@ -16,6 +16,7 @@ stdlib_rt_srcs= \
 	$(STDLIB)/rt/$(PLATFORM)/stat.ha \
 	$(STDLIB)/rt/$(PLATFORM)/socket.ha \
 	$(STDLIB)/rt/$(ARCH)/jmp.ha \
+	$(STDLIB)/rt/$(ARCH)/backtrace.ha \
 	$(STDLIB)/rt/ensure.ha \
 	$(STDLIB)/rt/jmp.ha \
 	$(STDLIB)/rt/malloc.ha \
@@ -40,6 +41,7 @@ stdlib_asm=$(HARECACHE)/rt/syscall.o \
 	$(HARECACHE)/rt/setjmp.o \
 	$(HARECACHE)/rt/longjmp.o \
 	$(HARECACHE)/rt/restore.o \
+	$(HARECACHE)/rt/getfp.o \
 	$(HARECACHE)/rt/start.o
 
 $(HARECACHE)/rt/syscall.o: $(STDLIB)/rt/$(PLATFORM)/syscall$(ARCH).s
@@ -62,6 +64,11 @@ $(HARECACHE)/rt/restore.o: $(STDLIB)/rt/$(ARCH)/restore.s
 	@mkdir -p $(HARECACHE)/rt
 	@$(AS) -o $@ $<
 
+$(HARECACHE)/rt/getfp.o: $(STDLIB)/rt/$(ARCH)/getfp.s
+	@printf 'AS \t$@\n'
+	@mkdir -p $(HARECACHE)/rt
+	@$(AS) -o $@ $<
+
 $(HARECACHE)/rt/rt.a: $(HARECACHE)/rt/rt.o $(stdlib_asm)
 	@printf 'AR\t$@\n'
 	@$(AR) -csr $@ $(HARECACHE)/rt/rt.o $(stdlib_asm)
@@ -905,6 +912,7 @@ testlib_rt_srcs= \
 	$(STDLIB)/rt/$(PLATFORM)/stat.ha \
 	$(STDLIB)/rt/$(PLATFORM)/socket.ha \
 	$(STDLIB)/rt/$(ARCH)/jmp.ha \
+	$(STDLIB)/rt/$(ARCH)/backtrace.ha \
 	$(STDLIB)/rt/ensure.ha \
 	$(STDLIB)/rt/jmp.ha \
 	$(STDLIB)/rt/malloc.ha \
@@ -933,6 +941,7 @@ testlib_asm=$(TESTCACHE)/rt/syscall.o \
 	$(TESTCACHE)/rt/setjmp.o \
 	$(TESTCACHE)/rt/longjmp.o \
 	$(TESTCACHE)/rt/restore.o \
+	$(TESTCACHE)/rt/getfp.o \
 	$(TESTCACHE)/rt/start.o
 
 $(TESTCACHE)/rt/syscall.o: $(STDLIB)/rt/$(PLATFORM)/syscall$(ARCH).s
@@ -955,6 +964,11 @@ $(TESTCACHE)/rt/restore.o: $(STDLIB)/rt/$(ARCH)/restore.s
 	@mkdir -p $(TESTCACHE)/rt
 	@$(AS) -o $@ $<
 
+$(TESTCACHE)/rt/getfp.o: $(STDLIB)/rt/$(ARCH)/getfp.s
+	@printf 'AS \t$@\n'
+	@mkdir -p $(TESTCACHE)/rt
+	@$(AS) -o $@ $<
+
 $(TESTCACHE)/rt/rt.a: $(TESTCACHE)/rt/rt.o $(testlib_asm)
 	@printf 'AR\t$@\n'
 	@$(AR) -csr $@ $(TESTCACHE)/rt/rt.o $(testlib_asm)