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Use frame pointer to walk ARM stack on iOS.

Browse source 
Review URL: http://breakpad.appspot.com/314001

git-svn-id: http://google-breakpad.googlecode.com/svn/trunk@869 4c0a9323-5329-0410-9bdc-e9ce6186880e
This commit is contained in:
qsr@chromium.org 2011-10-17 13:42:35 +00:00
parent 375928a0a6
commit 01596d3bc1
5 changed files with 280 additions and 30 deletions
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9
src/google_breakpad/common/minidump_cpu_arm.h
View file

@ -120,10 +120,11 @@ typedef struct {
* purpose.
*/
enum MDARMRegisterNumbers {
MD_CONTEXT_ARM_REG_FP = 11,
MD_CONTEXT_ARM_REG_SP = 13,
MD_CONTEXT_ARM_REG_LR = 14,
MD_CONTEXT_ARM_REG_PC = 15
MD_CONTEXT_ARM_REG_IOS_FP = 7,
MD_CONTEXT_ARM_REG_FP = 11,
MD_CONTEXT_ARM_REG_SP = 13,
MD_CONTEXT_ARM_REG_LR = 14,
MD_CONTEXT_ARM_REG_PC = 15
};
/* For (MDRawContextARM).context_flags. These values indicate the type of

8
src/processor/stackwalker.cc
View file

@ -44,6 +44,7 @@
#include "google_breakpad/processor/source_line_resolver_interface.h"
#include "google_breakpad/processor/stack_frame.h"
#include "google_breakpad/processor/symbol_supplier.h"
#include "google_breakpad/processor/system_info.h"
#include "processor/linked_ptr.h"
#include "processor/logging.h"
#include "processor/scoped_ptr.h"
@ -187,10 +188,13 @@ Stackwalker* Stackwalker::StackwalkerForCPU(
break;
case MD_CONTEXT_ARM:
int fp_register = -1;
if (system_info->os_short == "ios")
fp_register = MD_CONTEXT_ARM_REG_IOS_FP;
cpu_stackwalker = new StackwalkerARM(system_info,
context->GetContextARM(),
memory, modules, supplier,
resolver);
fp_register, memory, modules,
supplier, resolver);
break;
}

79
src/processor/stackwalker_arm.cc
View file

@ -33,7 +33,6 @@
//
// Author: Mark Mentovai, Ted Mielczarek, Jim Blandy
#include "google_breakpad/processor/call_stack.h"
#include "google_breakpad/processor/memory_region.h"
#include "google_breakpad/processor/source_line_resolver_interface.h"
@ -48,12 +47,13 @@ namespace google_breakpad {
StackwalkerARM::StackwalkerARM(const SystemInfo *system_info,
const MDRawContextARM *context,
int fp_register,
MemoryRegion *memory,
const CodeModules *modules,
SymbolSupplier *supplier,
SourceLineResolverInterface *resolver)
: Stackwalker(system_info, memory, modules, supplier, resolver),
context_(context),
context_(context), fp_register_(fp_register),
context_frame_validity_(StackFrameARM::CONTEXT_VALID_ALL) { }
@ -70,7 +70,7 @@ StackFrame* StackwalkerARM::GetContextFrame() {
frame->context = *context_;
frame->context_validity = context_frame_validity_;
frame->trust = StackFrame::FRAME_TRUST_CONTEXT;
frame->instruction = frame->context.iregs[15];
frame->instruction = frame->context.iregs[MD_CONTEXT_ARM_REG_PC];
return frame;
}
@ -125,8 +125,18 @@ StackFrameARM *StackwalkerARM::GetCallerByCFIFrameInfo(
CFIFrameInfo::RegisterValueMap<u_int32_t>::iterator entry =
caller_registers.find(".ra");
if (entry != caller_registers.end()) {
frame->context_validity |= StackFrameARM::CONTEXT_VALID_PC;
frame->context.iregs[MD_CONTEXT_ARM_REG_PC] = entry->second;
if (fp_register_ == -1) {
frame->context_validity |= StackFrameARM::CONTEXT_VALID_PC;
frame->context.iregs[MD_CONTEXT_ARM_REG_PC] = entry->second;
} else {
// The CFI updated the link register and not the program counter.
// Handle getting the program counter from the link register.
frame->context_validity |= StackFrameARM::CONTEXT_VALID_PC;
frame->context_validity |= StackFrameARM::CONTEXT_VALID_LR;
frame->context.iregs[MD_CONTEXT_ARM_REG_LR] = entry->second;
frame->context.iregs[MD_CONTEXT_ARM_REG_PC] =
last_frame->context.iregs[MD_CONTEXT_ARM_REG_LR];
}
}
}
// If the CFI doesn't recover the SP explicitly, then use .cfa.
@ -154,7 +164,7 @@ StackFrameARM *StackwalkerARM::GetCallerByStackScan(
StackFrameARM *last_frame = static_cast<StackFrameARM *>(frames.back());
u_int32_t last_sp = last_frame->context.iregs[MD_CONTEXT_ARM_REG_SP];
u_int32_t caller_sp, caller_pc;
if (!ScanForReturnAddress(last_sp, &caller_sp, &caller_pc)) {
// No plausible return address was found.
return NULL;
@ -179,6 +189,52 @@ StackFrameARM *StackwalkerARM::GetCallerByStackScan(
return frame;
}
StackFrameARM *StackwalkerARM::GetCallerByFramePointer(
const vector<StackFrame *> &frames) {
StackFrameARM *last_frame = static_cast<StackFrameARM *>(frames.back());
if (!(last_frame->context_validity &
StackFrameARM::RegisterValidFlag(fp_register_))) {
return NULL;
}
u_int32_t last_fp = last_frame->context.iregs[fp_register_];
u_int32_t caller_fp = 0;
if (last_fp && !memory_->GetMemoryAtAddress(last_fp, &caller_fp)) {
BPLOG(ERROR) << "Unable to read caller_fp from last_fp: 0x"
<< std::hex << last_fp;
return NULL;
}
u_int32_t caller_lr = 0;
if (last_fp && !memory_->GetMemoryAtAddress(last_fp + 4, &caller_lr)) {
BPLOG(ERROR) << "Unable to read caller_lr from last_fp + 4: 0x"
<< std::hex << (last_fp + 4);
return NULL;
}
u_int32_t caller_sp = last_fp ? last_fp + 8 :
last_frame->context.iregs[MD_CONTEXT_ARM_REG_SP];
// Create a new stack frame (ownership will be transferred to the caller)
// and fill it in.
StackFrameARM *frame = new StackFrameARM();
frame->trust = StackFrame::FRAME_TRUST_FP;
frame->context = last_frame->context;
frame->context.iregs[fp_register_] = caller_fp;
frame->context.iregs[MD_CONTEXT_ARM_REG_SP] = caller_sp;
frame->context.iregs[MD_CONTEXT_ARM_REG_PC] =
last_frame->context.iregs[MD_CONTEXT_ARM_REG_LR];
frame->context.iregs[MD_CONTEXT_ARM_REG_LR] = caller_lr;
frame->context_validity = StackFrameARM::CONTEXT_VALID_PC |
StackFrameARM::CONTEXT_VALID_LR |
StackFrameARM::RegisterValidFlag(fp_register_) |
StackFrameARM::CONTEXT_VALID_SP;
return frame;
}
StackFrame* StackwalkerARM::GetCallerFrame(const CallStack *stack) {
if (!memory_ || !stack) {
BPLOG(ERROR) << "Can't get caller frame without memory or stack";
@ -196,10 +252,13 @@ StackFrame* StackwalkerARM::GetCallerFrame(const CallStack *stack) {
frame.reset(GetCallerByCFIFrameInfo(frames, cfi_frame_info.get()));
// If CFI failed, or there wasn't CFI available, fall back
// to stack scanning.
if (!frame.get()) {
// to frame pointer, if this is configured.
if (fp_register_ >= 0 && !frame.get())
frame.reset(GetCallerByFramePointer(frames));
// If everuthing failed, fall back to stack scanning.
if (!frame.get())
frame.reset(GetCallerByStackScan(frames));
}
// If nothing worked, tell the caller.
if (!frame.get())
@ -225,7 +284,7 @@ StackFrame* StackwalkerARM::GetCallerFrame(const CallStack *stack) {
// match up with the line that contains the function call. Callers that
// require the exact return address value may access
// frame->context.iregs[MD_CONTEXT_ARM_REG_PC].
frame->instruction = frame->context.iregs[MD_CONTEXT_ARM_REG_PC] - 1;
frame->instruction = frame->context.iregs[MD_CONTEXT_ARM_REG_PC] - 2;
return frame.release();
}

12
src/processor/stackwalker_arm.h
View file

@ -40,7 +40,6 @@
#ifndef PROCESSOR_STACKWALKER_ARM_H__
#define PROCESSOR_STACKWALKER_ARM_H__
#include "google_breakpad/common/breakpad_types.h"
#include "google_breakpad/common/minidump_format.h"
#include "google_breakpad/processor/stackwalker.h"
@ -57,6 +56,7 @@ class StackwalkerARM : public Stackwalker {
// to the base Stackwalker constructor.
StackwalkerARM(const SystemInfo *system_info,
const MDRawContextARM *context,
int fp_register,
MemoryRegion *memory,
const CodeModules *modules,
SymbolSupplier *supplier,
@ -78,8 +78,12 @@ class StackwalkerARM : public Stackwalker {
StackFrameARM *GetCallerByCFIFrameInfo(const vector<StackFrame *> &frames,
CFIFrameInfo *cfi_frame_info);
// Use the frame pointer. The caller takes ownership of the returned frame.
// Return NULL on failure.
StackFrameARM *GetCallerByFramePointer(const vector<StackFrame *> &frames);
// Scan the stack for plausible return addresses. The caller takes ownership
// of the returned frame. Return NULL on failure.
// of the returned frame. Return NULL on failure.
StackFrameARM *GetCallerByStackScan(const vector<StackFrame *> &frames);
// Stores the CPU context corresponding to the youngest stack frame, to
@ -90,6 +94,10 @@ class StackwalkerARM : public Stackwalker {
// CONTEXT_VALID_ALL in real use; it is only changeable for the sake of
// unit tests.
int context_frame_validity_;
// The register to use a as frame pointer. The value is -1 if frame pointer
// cannot be used.
int fp_register_;
};

202
src/processor/stackwalker_arm_unittest.cc
View file

@ -116,7 +116,7 @@ class StackwalkerARMFixture {
for (size_t i = 0; i < sizeof(*raw_context); i++)
reinterpret_cast<u_int8_t *>(raw_context)[i] = (x += 17);
}
SystemInfo system_info;
MDRawContextARM raw_context;
Section stack_section;
@ -136,7 +136,7 @@ TEST_F(SanityCheck, NoResolver) {
// Since we have no call frame information, and all unwinding
// requires call frame information, the stack walk will end after
// the first frame.
StackwalkerARM walker(&system_info, &raw_context, &stack_region, &modules,
StackwalkerARM walker(&system_info, &raw_context, -1, &stack_region, &modules,
NULL, NULL);
// This should succeed even without a resolver or supplier.
ASSERT_TRUE(walker.Walk(&call_stack));
@ -154,7 +154,7 @@ TEST_F(GetContextFrame, Simple) {
// Since we have no call frame information, and all unwinding
// requires call frame information, the stack walk will end after
// the first frame.
StackwalkerARM walker(&system_info, &raw_context, &stack_region, &modules,
StackwalkerARM walker(&system_info, &raw_context, -1, &stack_region, &modules,
&supplier, &resolver);
ASSERT_TRUE(walker.Walk(&call_stack));
frames = call_stack.frames();
@ -201,7 +201,7 @@ TEST_F(GetCallerFrame, ScanWithoutSymbols) {
raw_context.iregs[MD_CONTEXT_ARM_REG_PC] = 0x40005510;
raw_context.iregs[MD_CONTEXT_ARM_REG_SP] = stack_section.start().Value();
StackwalkerARM walker(&system_info, &raw_context, &stack_region, &modules,
StackwalkerARM walker(&system_info, &raw_context, -1, &stack_region, &modules,
&supplier, &resolver);
ASSERT_TRUE(walker.Walk(&call_stack));
frames = call_stack.frames();
@ -264,7 +264,7 @@ TEST_F(GetCallerFrame, ScanWithFunctionSymbols) {
// The calling frame's function.
"FUNC 100 400 10 marsupial\n");
StackwalkerARM walker(&system_info, &raw_context, &stack_region, &modules,
StackwalkerARM walker(&system_info, &raw_context, -1, &stack_region, &modules,
&supplier, &resolver);
ASSERT_TRUE(walker.Walk(&call_stack));
frames = call_stack.frames();
@ -374,8 +374,8 @@ struct CFIFixture: public StackwalkerARMFixture {
RegionFromSection();
raw_context.iregs[MD_CONTEXT_ARM_REG_SP] = stack_section.start().Value();
StackwalkerARM walker(&system_info, &raw_context, &stack_region, &modules,
&supplier, &resolver);
StackwalkerARM walker(&system_info, &raw_context, -1, &stack_region,
&modules, &supplier, &resolver);
walker.SetContextFrameValidity(context_frame_validity);
ASSERT_TRUE(walker.Walk(&call_stack));
frames = call_stack.frames();
@ -417,7 +417,7 @@ struct CFIFixture: public StackwalkerARMFixture {
EXPECT_EQ(expected.iregs[MD_CONTEXT_ARM_REG_PC],
frame1->context.iregs[MD_CONTEXT_ARM_REG_PC]);
EXPECT_EQ(expected.iregs[MD_CONTEXT_ARM_REG_PC],
frame1->instruction + 1);
frame1->instruction + 2);
EXPECT_EQ("epictetus", frame1->function_name);
}
@ -564,9 +564,9 @@ TEST_F(CFI, At4006) {
// move in the wrong direction.
TEST_F(CFI, RejectBackwards) {
raw_context.iregs[MD_CONTEXT_ARM_REG_PC] = 0x40006000;
raw_context.iregs[MD_CONTEXT_ARM_REG_SP] = 0x80000000;
raw_context.iregs[MD_CONTEXT_ARM_REG_SP] = 0x80000000;
raw_context.iregs[MD_CONTEXT_ARM_REG_LR] = 0x40005510;
StackwalkerARM walker(&system_info, &raw_context, &stack_region, &modules,
StackwalkerARM walker(&system_info, &raw_context, -1, &stack_region, &modules,
&supplier, &resolver);
ASSERT_TRUE(walker.Walk(&call_stack));
frames = call_stack.frames();
@ -576,11 +576,189 @@ TEST_F(CFI, RejectBackwards) {
// Check that we reject rules whose expressions' evaluation fails.
TEST_F(CFI, RejectBadExpressions) {
raw_context.iregs[MD_CONTEXT_ARM_REG_PC] = 0x40007000;
raw_context.iregs[MD_CONTEXT_ARM_REG_SP] = 0x80000000;
StackwalkerARM walker(&system_info, &raw_context, &stack_region, &modules,
raw_context.iregs[MD_CONTEXT_ARM_REG_SP] = 0x80000000;
StackwalkerARM walker(&system_info, &raw_context, -1, &stack_region, &modules,
&supplier, &resolver);
ASSERT_TRUE(walker.Walk(&call_stack));
frames = call_stack.frames();
ASSERT_EQ(1U, frames->size());
}
class StackwalkerARMFixtureIOS : public StackwalkerARMFixture {
public:
StackwalkerARMFixtureIOS() {
system_info.os = "iOS";
system_info.os_short = "ios";
}
};
class GetFramesByFramePointer: public StackwalkerARMFixtureIOS, public Test { };
TEST_F(GetFramesByFramePointer, OnlyFramePointer) {
stack_section.start() = 0x80000000;
u_int32_t return_address1 = 0x50000100;
u_int32_t return_address2 = 0x50000900;
Label frame1_sp, frame2_sp;
Label frame1_fp, frame2_fp;
stack_section
// frame 0
.Append(32, 0) // Whatever values on the stack.
.D32(0x0000000D) // junk that's not
.D32(0xF0000000) // a return address.
.Mark(&frame1_fp) // Next fp will point to the next value.
.D32(frame2_fp) // Save current frame pointer.
.D32(return_address2) // Save current link register.
.Mark(&frame1_sp)
// frame 1
.Append(32, 0) // Whatever values on the stack.
.D32(0x0000000D) // junk that's not
.D32(0xF0000000) // a return address.
.Mark(&frame2_fp)
.D32(0)
.D32(0)
.Mark(&frame2_sp)
// frame 2
.Append(32, 0) // Whatever values on the stack.
.D32(0x0000000D) // junk that's not
.D32(0xF0000000); // a return address.
RegionFromSection();
raw_context.iregs[MD_CONTEXT_ARM_REG_PC] = 0x40005510;
raw_context.iregs[MD_CONTEXT_ARM_REG_LR] = return_address1;
raw_context.iregs[MD_CONTEXT_ARM_REG_IOS_FP] = frame1_fp.Value();
raw_context.iregs[MD_CONTEXT_ARM_REG_SP] = stack_section.start().Value();
StackwalkerARM walker(&system_info, &raw_context, MD_CONTEXT_ARM_REG_IOS_FP,
&stack_region, &modules, &supplier, &resolver);
ASSERT_TRUE(walker.Walk(&call_stack));
frames = call_stack.frames();
ASSERT_EQ(3U, frames->size());
StackFrameARM *frame0 = static_cast<StackFrameARM *>(frames->at(0));
EXPECT_EQ(StackFrame::FRAME_TRUST_CONTEXT, frame0->trust);
ASSERT_EQ(StackFrameARM::CONTEXT_VALID_ALL, frame0->context_validity);
EXPECT_EQ(0, memcmp(&raw_context, &frame0->context, sizeof(raw_context)));
StackFrameARM *frame1 = static_cast<StackFrameARM *>(frames->at(1));
EXPECT_EQ(StackFrame::FRAME_TRUST_FP, frame1->trust);
ASSERT_EQ((StackFrameARM::CONTEXT_VALID_PC |
StackFrameARM::CONTEXT_VALID_LR |
StackFrameARM::RegisterValidFlag(MD_CONTEXT_ARM_REG_IOS_FP) |
StackFrameARM::CONTEXT_VALID_SP),
frame1->context_validity);
EXPECT_EQ(return_address1, frame1->context.iregs[MD_CONTEXT_ARM_REG_PC]);
EXPECT_EQ(return_address2, frame1->context.iregs[MD_CONTEXT_ARM_REG_LR]);
EXPECT_EQ(frame1_sp.Value(), frame1->context.iregs[MD_CONTEXT_ARM_REG_SP]);
EXPECT_EQ(frame2_fp.Value(),
frame1->context.iregs[MD_CONTEXT_ARM_REG_IOS_FP]);
StackFrameARM *frame2 = static_cast<StackFrameARM *>(frames->at(2));
EXPECT_EQ(StackFrame::FRAME_TRUST_FP, frame2->trust);
ASSERT_EQ((StackFrameARM::CONTEXT_VALID_PC |
StackFrameARM::CONTEXT_VALID_LR |
StackFrameARM::RegisterValidFlag(MD_CONTEXT_ARM_REG_IOS_FP) |
StackFrameARM::CONTEXT_VALID_SP),
frame2->context_validity);
EXPECT_EQ(return_address2, frame2->context.iregs[MD_CONTEXT_ARM_REG_PC]);
EXPECT_EQ(0, frame2->context.iregs[MD_CONTEXT_ARM_REG_LR]);
EXPECT_EQ(frame2_sp.Value(), frame2->context.iregs[MD_CONTEXT_ARM_REG_SP]);
EXPECT_EQ(0, frame2->context.iregs[MD_CONTEXT_ARM_REG_IOS_FP]);
}
TEST_F(GetFramesByFramePointer, FramePointerAndCFI) {
// Provide the standatd STACK CFI records that is obtained when exmining an
// executable produced by XCode.
SetModuleSymbols(&module1,
// Adding a function in CFI.
"FUNC 4000 1000 10 enchiridion\n"
"STACK CFI INIT 4000 100 .cfa: sp 0 + .ra: lr\n"
"STACK CFI 4001 .cfa: sp 8 + .ra: .cfa -4 + ^"
" r7: .cfa -8 + ^\n"
"STACK CFI 4002 .cfa: r7 8 +\n"
);
stack_section.start() = 0x80000000;
u_int32_t return_address1 = 0x40004010;
u_int32_t return_address2 = 0x50000900;
Label frame1_sp, frame2_sp;
Label frame1_fp, frame2_fp;
stack_section
// frame 0
.Append(32, 0) // Whatever values on the stack.
.D32(0x0000000D) // junk that's not
.D32(0xF0000000) // a return address.
.Mark(&frame1_fp) // Next fp will point to the next value.
.D32(frame2_fp) // Save current frame pointer.
.D32(return_address2) // Save current link register.
.Mark(&frame1_sp)
// frame 1
.Append(32, 0) // Whatever values on the stack.
.D32(0x0000000D) // junk that's not
.D32(0xF0000000) // a return address.
.Mark(&frame2_fp)
.D32(0)
.D32(0)
.Mark(&frame2_sp)
// frame 2
.Append(32, 0) // Whatever values on the stack.
.D32(0x0000000D) // junk that's not
.D32(0xF0000000); // a return address.
RegionFromSection();
raw_context.iregs[MD_CONTEXT_ARM_REG_PC] = 0x50000400;
raw_context.iregs[MD_CONTEXT_ARM_REG_LR] = return_address1;
raw_context.iregs[MD_CONTEXT_ARM_REG_IOS_FP] = frame1_fp.Value();
raw_context.iregs[MD_CONTEXT_ARM_REG_SP] = stack_section.start().Value();
StackwalkerARM walker(&system_info, &raw_context, MD_CONTEXT_ARM_REG_IOS_FP,
&stack_region, &modules, &supplier, &resolver);
ASSERT_TRUE(walker.Walk(&call_stack));
frames = call_stack.frames();
ASSERT_EQ(3U, frames->size());
StackFrameARM *frame0 = static_cast<StackFrameARM *>(frames->at(0));
EXPECT_EQ(StackFrame::FRAME_TRUST_CONTEXT, frame0->trust);
ASSERT_EQ(StackFrameARM::CONTEXT_VALID_ALL, frame0->context_validity);
EXPECT_EQ(0, memcmp(&raw_context, &frame0->context, sizeof(raw_context)));
StackFrameARM *frame1 = static_cast<StackFrameARM *>(frames->at(1));
EXPECT_EQ(StackFrame::FRAME_TRUST_FP, frame1->trust);
ASSERT_EQ((StackFrameARM::CONTEXT_VALID_PC |
StackFrameARM::CONTEXT_VALID_LR |
StackFrameARM::RegisterValidFlag(MD_CONTEXT_ARM_REG_IOS_FP) |
StackFrameARM::CONTEXT_VALID_SP),
frame1->context_validity);
EXPECT_EQ(return_address1, frame1->context.iregs[MD_CONTEXT_ARM_REG_PC]);
EXPECT_EQ(return_address2, frame1->context.iregs[MD_CONTEXT_ARM_REG_LR]);
EXPECT_EQ(frame1_sp.Value(), frame1->context.iregs[MD_CONTEXT_ARM_REG_SP]);
EXPECT_EQ(frame2_fp.Value(),
frame1->context.iregs[MD_CONTEXT_ARM_REG_IOS_FP]);
EXPECT_EQ("enchiridion", frame1->function_name);
EXPECT_EQ(0x40004000U, frame1->function_base);
StackFrameARM *frame2 = static_cast<StackFrameARM *>(frames->at(2));
EXPECT_EQ(StackFrame::FRAME_TRUST_CFI, frame2->trust);
ASSERT_EQ((StackFrameARM::CONTEXT_VALID_PC |
StackFrameARM::CONTEXT_VALID_LR |
StackFrameARM::RegisterValidFlag(MD_CONTEXT_ARM_REG_IOS_FP) |
StackFrameARM::CONTEXT_VALID_SP),
frame2->context_validity);
EXPECT_EQ(return_address2, frame2->context.iregs[MD_CONTEXT_ARM_REG_PC]);
EXPECT_EQ(0, frame2->context.iregs[MD_CONTEXT_ARM_REG_LR]);
EXPECT_EQ(frame2_sp.Value(), frame2->context.iregs[MD_CONTEXT_ARM_REG_SP]);
EXPECT_EQ(0, frame2->context.iregs[MD_CONTEXT_ARM_REG_IOS_FP]);
}