[ltrace-commits] 01/03: Fix bugs in fetch backend of powerpc64le
Petr Machata
pmachata-guest at moszumanska.debian.org
Fri Aug 8 21:56:59 UTC 2014
This is an automated email from the git hooks/post-receive script.
pmachata-guest pushed a commit to branch master
in repository ltrace.
commit 35a9677dc9dcb7909ebd28f30200474d7e8b660f
Author: Petr Machata <pmachata at redhat.com>
Date: Fri Aug 8 23:10:21 2014 +0200
Fix bugs in fetch backend of powerpc64le
- One bug was in a function that returned a small structure and whose
first argument was a pointer that pointed to stack. The old code
assumed that meant that the structure was returned by implicit
reference instead of in registers.
- Another was in passing large HFA's (larger than 8 elements) in
arguments, and in returning HFA's.
---
sysdeps/linux-gnu/ppc/fetch.c | 150 ++++++++++++++++++++----------------------
1 file changed, 70 insertions(+), 80 deletions(-)
diff --git a/sysdeps/linux-gnu/ppc/fetch.c b/sysdeps/linux-gnu/ppc/fetch.c
index c9381c3..15dd8b4 100644
--- a/sysdeps/linux-gnu/ppc/fetch.c
+++ b/sysdeps/linux-gnu/ppc/fetch.c
@@ -1,6 +1,6 @@
/*
* This file is part of ltrace.
- * Copyright (C) 2012 Petr Machata, Red Hat Inc.
+ * Copyright (C) 2012, 2014 Petr Machata, Red Hat Inc.
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License as
@@ -57,7 +57,7 @@ struct fetch_context {
arch_addr_t stack_pointer;
int greg;
int freg;
- int ret_struct;
+ bool ret_struct;
union {
gregs32_t r32;
@@ -65,11 +65,29 @@ struct fetch_context {
} regs;
struct fpregs_t fpregs;
int vgreg;
- int struct_size;
- int struct_hfa_size;
- int struct_hfa_count;
};
+static bool
+is_eligible_hfa(struct arg_type_info *info,
+ struct arg_type_info **hfa_infop, size_t *hfa_countp)
+{
+ size_t hfa_count;
+ struct arg_type_info *hfa_info = type_get_hfa_type(info, &hfa_count);
+
+ if (hfa_info != NULL && hfa_count <= 8
+ && (hfa_info->type == ARGTYPE_FLOAT
+ || hfa_info->type == ARGTYPE_DOUBLE)) {
+
+ if (hfa_infop != NULL)
+ *hfa_infop = hfa_info;
+ if (hfa_countp != NULL)
+ *hfa_countp = hfa_count;
+ return true;
+ }
+
+ return false;
+}
+
static int
fetch_context_init(struct process *proc, struct fetch_context *context)
{
@@ -125,31 +143,37 @@ arch_fetch_arg_init(enum tof type, struct process *proc,
}
context->vgreg = context->greg;
- context->struct_size = 0;
- context->struct_hfa_size = 0;
- context->struct_hfa_count = 0;
/* Aggregates or unions of any length, and character strings
* of length longer than 8 bytes, will be returned in a
* storage buffer allocated by the caller. The caller will
* pass the address of this buffer as a hidden first argument
* in r3, causing the first explicit argument to be passed in
- * r4. */
- context->ret_struct = ret_info->type == ARGTYPE_STRUCT;
- if (context->ret_struct) {
+ * r4.
+ */
+
+ context->ret_struct = false;
+
#if _CALL_ELF == 2
- /* if R3 points to stack, parameters will be in R4. */
- uint64_t pstack_end = ptrace(PTRACE_PEEKTEXT, proc->pid,
- proc->stack_pointer, 0);
- if (((arch_addr_t)context->regs.r64[3] > proc->stack_pointer)
- && (context->regs.r64[3] < pstack_end)) {
- context->greg++;
- context->stack_pointer += 8;
- }
+ /* With ELFv2 ABI, aggregates that consist (recursively) only
+ * of members of the same floating-point or vector type, are
+ * passed in a series of floating-point resp. vector
+ * registers. Additionally, when returning any aggregate of
+ * up to 16 bytes, general-purpose registers are used. */
+ if (ret_info->type == ARGTYPE_STRUCT
+ && ! is_eligible_hfa(ret_info, NULL, NULL)
+ && type_sizeof(proc, ret_info) > 16) {
+
+ context->ret_struct = true;
+ context->greg++;
+ context->stack_pointer += 8;
+ }
#else
+ if (ret_info->type == ARGTYPE_STRUCT) {
+ context->ret_struct = true;
context->greg++;
-#endif
}
+#endif
return context;
}
@@ -336,27 +360,27 @@ allocate_hfa(struct fetch_context *ctx, struct process *proc,
if (sz == (size_t)-1)
return -1;
- ctx->struct_hfa_size += sz;
-
/* There are two changes regarding structure return types:
- * * heterogeneous float/vector structs are returned
- * in (multiple) FP/vector registers,
- * instead of via implicit reference.
- * * small structs (up to 16 bytes) are return
- * in one or two GPRs, instead of via implicit reference.
+ * * heterogeneous float/vector structs are returned in
+ * (multiple) FP/vector registers, instead of via implicit
+ * reference.
+ * * small structs (up to 16 bytes) are return in one or two
+ * GPRs, instead of via implicit reference.
*
* Other structures (larger than 16 bytes, not heterogeneous)
* are still returned via implicit reference (i.e. a pointer
* to memory where to return the struct being passed in r3).
- * Of course, whether or not an implicit reference pointer
- * is present will shift the remaining arguments,
- * so you need to get this right for ELFv2 in order
- * to get the arguments correct.
+ * Of course, whether or not an implicit reference pointer is
+ * present will shift the remaining arguments, so you need to
+ * get this right for ELFv2 in order to get the arguments
+ * correct.
+ *
* If an actual parameter is known to correspond to an HFA
* formal parameter, each element is passed in the next
* available floating-point argument register starting at fp1
* until the fp13. The remaining elements of the aggregate are
- * passed on the stack. */
+ * passed on the stack.
+ */
size_t slot_off = 0;
unsigned char *buf = value_reserve(valuep, sz);
@@ -366,26 +390,17 @@ allocate_hfa(struct fetch_context *ctx, struct process *proc,
struct arg_type_info *hfa_info = type_get_simple(hfa_type);
size_t hfa_sz = type_sizeof(proc, hfa_info);
- if (hfa_count > 8)
- ctx->struct_hfa_count += hfa_count;
-
while (hfa_count > 0 && ctx->freg <= 13) {
- int rc;
struct value tmp;
-
value_init(&tmp, proc, NULL, hfa_info, 0);
+ int rc = allocate_float(ctx, proc, hfa_info,
+ &tmp, slot_off, true);
+ if (rc == 0)
+ memcpy(buf, value_get_data(&tmp, NULL), hfa_sz);
+ value_destroy(&tmp);
- /* Hetereogeneous struct - get value on GPR or stack. */
- if (((hfa_type == ARGTYPE_FLOAT
- || hfa_type == ARGTYPE_DOUBLE)
- && hfa_count <= 8))
- rc = allocate_float(ctx, proc, hfa_info, &tmp,
- slot_off, true);
- else
- rc = allocate_gpr(ctx, proc, hfa_info, &tmp,
- slot_off, true);
-
- memcpy(buf, value_get_data(&tmp, NULL), hfa_sz);
+ if (rc < 0)
+ return -1;
slot_off += hfa_sz;
buf += hfa_sz;
@@ -394,17 +409,13 @@ allocate_hfa(struct fetch_context *ctx, struct process *proc,
slot_off = 0;
ctx->vgreg++;
}
-
- value_destroy(&tmp);
- if (rc < 0)
- return -1;
}
if (hfa_count == 0)
return 0;
/* if no remaining FP, GPR corresponding to slot is used
- * Mostly it is in part of r10. */
- if (ctx->struct_hfa_size <= 64 && ctx->vgreg == 10) {
+ * Mostly it is in part of r10. */
+ if (ctx->vgreg == 10) {
while (ctx->vgreg <= 10) {
struct value tmp;
value_init(&tmp, proc, NULL, hfa_info, 0);
@@ -428,11 +439,8 @@ allocate_hfa(struct fetch_context *ctx, struct process *proc,
}
}
- if (hfa_count == 0)
- return 0;
-
/* Remaining values are on stack */
- while (hfa_count) {
+ while (hfa_count > 0) {
struct value tmp;
value_init(&tmp, proc, NULL, hfa_info, 0);
@@ -459,7 +467,7 @@ allocate_argument(struct fetch_context *ctx, struct process *proc,
case ARGTYPE_FLOAT:
case ARGTYPE_DOUBLE:
return allocate_float(ctx, proc, info, valuep,
- 8 - type_sizeof(proc,info), false);
+ 8 - type_sizeof(proc,info), false);
case ARGTYPE_STRUCT:
if (proc->e_machine == EM_PPC) {
@@ -468,13 +476,10 @@ allocate_argument(struct fetch_context *ctx, struct process *proc,
} else {
#if _CALL_ELF == 2
struct arg_type_info *hfa_info;
- size_t hfa_size;
- hfa_info = type_get_hfa_type(info, &hfa_size);
- if (hfa_info != NULL ) {
- size_t sz = type_sizeof(proc, info);
- ctx->struct_size += sz;
+ size_t hfa_count;
+ if (is_eligible_hfa(info, &hfa_info, &hfa_count)) {
return allocate_hfa(ctx, proc, info, valuep,
- hfa_info->type, hfa_size);
+ hfa_info->type, hfa_count);
}
#endif
/* PPC64: Fixed size aggregates and unions passed by
@@ -510,9 +515,6 @@ allocate_argument(struct fetch_context *ctx, struct process *proc,
if (sz == (size_t)-1)
return -1;
- if (ctx->ret_struct)
- ctx->struct_size += sz;
-
size_t slots = (sz + width - 1) / width; /* Round up. */
unsigned char *buf = value_reserve(valuep, slots * width);
if (buf == NULL)
@@ -605,19 +607,7 @@ arch_fetch_retval(struct fetch_context *ctx, enum tof type,
if (fetch_context_init(proc, ctx) < 0)
return -1;
-#if _CALL_ELF == 2
- void *ptr = (void *)(ctx->regs.r64[1]+32);
- uint64_t val = ptrace(PTRACE_PEEKTEXT, proc->pid, ptr, 0);
-
- if (ctx->ret_struct
- && ((ctx->struct_size > 64
- || ctx->struct_hfa_count > 8
- || (ctx->struct_hfa_size == 0 && ctx->struct_size > 56)
- || (ctx->regs.r64[3] == ctx->regs.r64[1]+32)
- || (ctx->regs.r64[3] == val )))) {
-#else
if (ctx->ret_struct) {
-#endif
assert(info->type == ARGTYPE_STRUCT);
uint64_t addr = read_gpr(ctx, proc, 3);
--
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