summaryrefslogtreecommitdiffstats
path: root/tools/profiler/lul/LulMain.cpp
diff options
context:
space:
mode:
Diffstat (limited to 'tools/profiler/lul/LulMain.cpp')
-rw-r--r--tools/profiler/lul/LulMain.cpp1963
1 files changed, 1963 insertions, 0 deletions
diff --git a/tools/profiler/lul/LulMain.cpp b/tools/profiler/lul/LulMain.cpp
new file mode 100644
index 000000000..2e78f03ec
--- /dev/null
+++ b/tools/profiler/lul/LulMain.cpp
@@ -0,0 +1,1963 @@
+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim: set ts=8 sts=2 et sw=2 tw=80: */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "LulMain.h"
+
+#include <string.h>
+#include <stdlib.h>
+#include <stdio.h>
+
+#include <algorithm> // std::sort
+#include <string>
+
+#include "mozilla/Assertions.h"
+#include "mozilla/ArrayUtils.h"
+#include "mozilla/CheckedInt.h"
+#include "mozilla/DebugOnly.h"
+#include "mozilla/MemoryChecking.h"
+#include "mozilla/Sprintf.h"
+
+#include "LulCommonExt.h"
+#include "LulElfExt.h"
+
+#include "LulMainInt.h"
+
+#include "platform-linux-lul.h" // for gettid()
+
+// Set this to 1 for verbose logging
+#define DEBUG_MAIN 0
+
+namespace lul {
+
+using std::string;
+using std::vector;
+using std::pair;
+using mozilla::CheckedInt;
+using mozilla::DebugOnly;
+
+
+// WARNING WARNING WARNING WARNING WARNING WARNING WARNING WARNING
+//
+// Some functions in this file are marked RUNS IN NO-MALLOC CONTEXT.
+// Any such function -- and, hence, the transitive closure of those
+// reachable from it -- must not do any dynamic memory allocation.
+// Doing so risks deadlock. There is exactly one root function for
+// the transitive closure: Lul::Unwind.
+//
+// WARNING WARNING WARNING WARNING WARNING WARNING WARNING WARNING
+
+
+////////////////////////////////////////////////////////////////
+// RuleSet //
+////////////////////////////////////////////////////////////////
+
+static const char*
+NameOf_DW_REG(int16_t aReg)
+{
+ switch (aReg) {
+ case DW_REG_CFA: return "cfa";
+#if defined(LUL_ARCH_x64) || defined(LUL_ARCH_x86)
+ case DW_REG_INTEL_XBP: return "xbp";
+ case DW_REG_INTEL_XSP: return "xsp";
+ case DW_REG_INTEL_XIP: return "xip";
+#elif defined(LUL_ARCH_arm)
+ case DW_REG_ARM_R7: return "r7";
+ case DW_REG_ARM_R11: return "r11";
+ case DW_REG_ARM_R12: return "r12";
+ case DW_REG_ARM_R13: return "r13";
+ case DW_REG_ARM_R14: return "r14";
+ case DW_REG_ARM_R15: return "r15";
+#else
+# error "Unsupported arch"
+#endif
+ default: return "???";
+ }
+}
+
+string
+LExpr::ShowRule(const char* aNewReg) const
+{
+ char buf[64];
+ string res = string(aNewReg) + "=";
+ switch (mHow) {
+ case UNKNOWN:
+ res += "Unknown";
+ break;
+ case NODEREF:
+ SprintfLiteral(buf, "%s+%d",
+ NameOf_DW_REG(mReg), (int)mOffset);
+ res += buf;
+ break;
+ case DEREF:
+ SprintfLiteral(buf, "*(%s+%d)",
+ NameOf_DW_REG(mReg), (int)mOffset);
+ res += buf;
+ break;
+ case PFXEXPR:
+ SprintfLiteral(buf, "PfxExpr-at-%d", (int)mOffset);
+ res += buf;
+ break;
+ default:
+ res += "???";
+ break;
+ }
+ return res;
+}
+
+void
+RuleSet::Print(void(*aLog)(const char*)) const
+{
+ char buf[96];
+ SprintfLiteral(buf, "[%llx .. %llx]: let ",
+ (unsigned long long int)mAddr,
+ (unsigned long long int)(mAddr + mLen - 1));
+ string res = string(buf);
+ res += mCfaExpr.ShowRule("cfa");
+ res += " in";
+ // For each reg we care about, print the recovery expression.
+#if defined(LUL_ARCH_x64) || defined(LUL_ARCH_x86)
+ res += mXipExpr.ShowRule(" RA");
+ res += mXspExpr.ShowRule(" SP");
+ res += mXbpExpr.ShowRule(" BP");
+#elif defined(LUL_ARCH_arm)
+ res += mR15expr.ShowRule(" R15");
+ res += mR7expr .ShowRule(" R7" );
+ res += mR11expr.ShowRule(" R11");
+ res += mR12expr.ShowRule(" R12");
+ res += mR13expr.ShowRule(" R13");
+ res += mR14expr.ShowRule(" R14");
+#else
+# error "Unsupported arch"
+#endif
+ aLog(res.c_str());
+}
+
+LExpr*
+RuleSet::ExprForRegno(DW_REG_NUMBER aRegno) {
+ switch (aRegno) {
+ case DW_REG_CFA: return &mCfaExpr;
+# if defined(LUL_ARCH_x64) || defined(LUL_ARCH_x86)
+ case DW_REG_INTEL_XIP: return &mXipExpr;
+ case DW_REG_INTEL_XSP: return &mXspExpr;
+ case DW_REG_INTEL_XBP: return &mXbpExpr;
+# elif defined(LUL_ARCH_arm)
+ case DW_REG_ARM_R15: return &mR15expr;
+ case DW_REG_ARM_R14: return &mR14expr;
+ case DW_REG_ARM_R13: return &mR13expr;
+ case DW_REG_ARM_R12: return &mR12expr;
+ case DW_REG_ARM_R11: return &mR11expr;
+ case DW_REG_ARM_R7: return &mR7expr;
+# else
+# error "Unknown arch"
+# endif
+ default: return nullptr;
+ }
+}
+
+RuleSet::RuleSet()
+{
+ mAddr = 0;
+ mLen = 0;
+ // The only other fields are of type LExpr and those are initialised
+ // by LExpr::LExpr().
+}
+
+
+////////////////////////////////////////////////////////////////
+// SecMap //
+////////////////////////////////////////////////////////////////
+
+// See header file LulMainInt.h for comments about invariants.
+
+SecMap::SecMap(void(*aLog)(const char*))
+ : mSummaryMinAddr(1)
+ , mSummaryMaxAddr(0)
+ , mUsable(true)
+ , mLog(aLog)
+{}
+
+SecMap::~SecMap() {
+ mRuleSets.clear();
+}
+
+// RUNS IN NO-MALLOC CONTEXT
+RuleSet*
+SecMap::FindRuleSet(uintptr_t ia) {
+ // Binary search mRuleSets to find one that brackets |ia|.
+ // lo and hi need to be signed, else the loop termination tests
+ // don't work properly. Note that this works correctly even when
+ // mRuleSets.size() == 0.
+
+ // Can't do this until the array has been sorted and preened.
+ MOZ_ASSERT(mUsable);
+
+ long int lo = 0;
+ long int hi = (long int)mRuleSets.size() - 1;
+ while (true) {
+ // current unsearched space is from lo to hi, inclusive.
+ if (lo > hi) {
+ // not found
+ return nullptr;
+ }
+ long int mid = lo + ((hi - lo) / 2);
+ RuleSet* mid_ruleSet = &mRuleSets[mid];
+ uintptr_t mid_minAddr = mid_ruleSet->mAddr;
+ uintptr_t mid_maxAddr = mid_minAddr + mid_ruleSet->mLen - 1;
+ if (ia < mid_minAddr) { hi = mid-1; continue; }
+ if (ia > mid_maxAddr) { lo = mid+1; continue; }
+ MOZ_ASSERT(mid_minAddr <= ia && ia <= mid_maxAddr);
+ return mid_ruleSet;
+ }
+ // NOTREACHED
+}
+
+// Add a RuleSet to the collection. The rule is copied in. Calling
+// this makes the map non-searchable.
+void
+SecMap::AddRuleSet(const RuleSet* rs) {
+ mUsable = false;
+ mRuleSets.push_back(*rs);
+}
+
+// Add a PfxInstr to the vector of such instrs, and return the index
+// in the vector. Calling this makes the map non-searchable.
+uint32_t
+SecMap::AddPfxInstr(PfxInstr pfxi) {
+ mUsable = false;
+ mPfxInstrs.push_back(pfxi);
+ return mPfxInstrs.size() - 1;
+}
+
+
+static bool
+CmpRuleSetsByAddrLE(const RuleSet& rs1, const RuleSet& rs2) {
+ return rs1.mAddr < rs2.mAddr;
+}
+
+// Prepare the map for searching. Completely remove any which don't
+// fall inside the specified range [start, +len).
+void
+SecMap::PrepareRuleSets(uintptr_t aStart, size_t aLen)
+{
+ if (mRuleSets.empty()) {
+ return;
+ }
+
+ MOZ_ASSERT(aLen > 0);
+ if (aLen == 0) {
+ // This should never happen.
+ mRuleSets.clear();
+ return;
+ }
+
+ // Sort by start addresses.
+ std::sort(mRuleSets.begin(), mRuleSets.end(), CmpRuleSetsByAddrLE);
+
+ // Detect any entry not completely contained within [start, +len).
+ // Set its length to zero, so that the next pass will remove it.
+ for (size_t i = 0; i < mRuleSets.size(); ++i) {
+ RuleSet* rs = &mRuleSets[i];
+ if (rs->mLen > 0 &&
+ (rs->mAddr < aStart || rs->mAddr + rs->mLen > aStart + aLen)) {
+ rs->mLen = 0;
+ }
+ }
+
+ // Iteratively truncate any overlaps and remove any zero length
+ // entries that might result, or that may have been present
+ // initially. Unless the input is seriously screwy, this is
+ // expected to iterate only once.
+ while (true) {
+ size_t i;
+ size_t n = mRuleSets.size();
+ size_t nZeroLen = 0;
+
+ if (n == 0) {
+ break;
+ }
+
+ for (i = 1; i < n; ++i) {
+ RuleSet* prev = &mRuleSets[i-1];
+ RuleSet* here = &mRuleSets[i];
+ MOZ_ASSERT(prev->mAddr <= here->mAddr);
+ if (prev->mAddr + prev->mLen > here->mAddr) {
+ prev->mLen = here->mAddr - prev->mAddr;
+ }
+ if (prev->mLen == 0)
+ nZeroLen++;
+ }
+
+ if (mRuleSets[n-1].mLen == 0) {
+ nZeroLen++;
+ }
+
+ // At this point, the entries are in-order and non-overlapping.
+ // If none of them are zero-length, we are done.
+ if (nZeroLen == 0) {
+ break;
+ }
+
+ // Slide back the entries to remove the zero length ones.
+ size_t j = 0; // The write-point.
+ for (i = 0; i < n; ++i) {
+ if (mRuleSets[i].mLen == 0) {
+ continue;
+ }
+ if (j != i) mRuleSets[j] = mRuleSets[i];
+ ++j;
+ }
+ MOZ_ASSERT(i == n);
+ MOZ_ASSERT(nZeroLen <= n);
+ MOZ_ASSERT(j == n - nZeroLen);
+ while (nZeroLen > 0) {
+ mRuleSets.pop_back();
+ nZeroLen--;
+ }
+
+ MOZ_ASSERT(mRuleSets.size() == j);
+ }
+
+ size_t n = mRuleSets.size();
+
+#ifdef DEBUG
+ // Do a final check on the rules: their address ranges must be
+ // ascending, non overlapping, non zero sized.
+ if (n > 0) {
+ MOZ_ASSERT(mRuleSets[0].mLen > 0);
+ for (size_t i = 1; i < n; ++i) {
+ RuleSet* prev = &mRuleSets[i-1];
+ RuleSet* here = &mRuleSets[i];
+ MOZ_ASSERT(prev->mAddr < here->mAddr);
+ MOZ_ASSERT(here->mLen > 0);
+ MOZ_ASSERT(prev->mAddr + prev->mLen <= here->mAddr);
+ }
+ }
+#endif
+
+ // Set the summary min and max address values.
+ if (n == 0) {
+ // Use the values defined in comments in the class declaration.
+ mSummaryMinAddr = 1;
+ mSummaryMaxAddr = 0;
+ } else {
+ mSummaryMinAddr = mRuleSets[0].mAddr;
+ mSummaryMaxAddr = mRuleSets[n-1].mAddr + mRuleSets[n-1].mLen - 1;
+ }
+ char buf[150];
+ SprintfLiteral(buf,
+ "PrepareRuleSets: %d entries, smin/smax 0x%llx, 0x%llx\n",
+ (int)n, (unsigned long long int)mSummaryMinAddr,
+ (unsigned long long int)mSummaryMaxAddr);
+ buf[sizeof(buf)-1] = 0;
+ mLog(buf);
+
+ // Is now usable for binary search.
+ mUsable = true;
+
+ if (0) {
+ mLog("\nRulesets after preening\n");
+ for (size_t i = 0; i < mRuleSets.size(); ++i) {
+ mRuleSets[i].Print(mLog);
+ mLog("\n");
+ }
+ mLog("\n");
+ }
+}
+
+bool SecMap::IsEmpty() {
+ return mRuleSets.empty();
+}
+
+
+////////////////////////////////////////////////////////////////
+// SegArray //
+////////////////////////////////////////////////////////////////
+
+// A SegArray holds a set of address ranges that together exactly
+// cover an address range, with no overlaps or holes. Each range has
+// an associated value, which in this case has been specialised to be
+// a simple boolean. The representation is kept to minimal canonical
+// form in which adjacent ranges with the same associated value are
+// merged together. Each range is represented by a |struct Seg|.
+//
+// SegArrays are used to keep track of which parts of the address
+// space are known to contain instructions.
+class SegArray {
+
+ public:
+ void add(uintptr_t lo, uintptr_t hi, bool val) {
+ if (lo > hi) {
+ return;
+ }
+ split_at(lo);
+ if (hi < UINTPTR_MAX) {
+ split_at(hi+1);
+ }
+ std::vector<Seg>::size_type iLo, iHi, i;
+ iLo = find(lo);
+ iHi = find(hi);
+ for (i = iLo; i <= iHi; ++i) {
+ mSegs[i].val = val;
+ }
+ preen();
+ }
+
+ // RUNS IN NO-MALLOC CONTEXT
+ bool getBoundingCodeSegment(/*OUT*/uintptr_t* rx_min,
+ /*OUT*/uintptr_t* rx_max, uintptr_t addr) {
+ std::vector<Seg>::size_type i = find(addr);
+ if (!mSegs[i].val) {
+ return false;
+ }
+ *rx_min = mSegs[i].lo;
+ *rx_max = mSegs[i].hi;
+ return true;
+ }
+
+ SegArray() {
+ Seg s(0, UINTPTR_MAX, false);
+ mSegs.push_back(s);
+ }
+
+ private:
+ struct Seg {
+ Seg(uintptr_t lo, uintptr_t hi, bool val) : lo(lo), hi(hi), val(val) {}
+ uintptr_t lo;
+ uintptr_t hi;
+ bool val;
+ };
+
+ void preen() {
+ for (std::vector<Seg>::iterator iter = mSegs.begin();
+ iter < mSegs.end()-1;
+ ++iter) {
+ if (iter[0].val != iter[1].val) {
+ continue;
+ }
+ iter[0].hi = iter[1].hi;
+ mSegs.erase(iter+1);
+ // Back up one, so as not to miss an opportunity to merge
+ // with the entry after this one.
+ --iter;
+ }
+ }
+
+ // RUNS IN NO-MALLOC CONTEXT
+ std::vector<Seg>::size_type find(uintptr_t a) {
+ long int lo = 0;
+ long int hi = (long int)mSegs.size();
+ while (true) {
+ // The unsearched space is lo .. hi inclusive.
+ if (lo > hi) {
+ // Not found. This can't happen.
+ return (std::vector<Seg>::size_type)(-1);
+ }
+ long int mid = lo + ((hi - lo) / 2);
+ uintptr_t mid_lo = mSegs[mid].lo;
+ uintptr_t mid_hi = mSegs[mid].hi;
+ if (a < mid_lo) { hi = mid-1; continue; }
+ if (a > mid_hi) { lo = mid+1; continue; }
+ return (std::vector<Seg>::size_type)mid;
+ }
+ }
+
+ void split_at(uintptr_t a) {
+ std::vector<Seg>::size_type i = find(a);
+ if (mSegs[i].lo == a) {
+ return;
+ }
+ mSegs.insert( mSegs.begin()+i+1, mSegs[i] );
+ mSegs[i].hi = a-1;
+ mSegs[i+1].lo = a;
+ }
+
+ void show() {
+ printf("<< %d entries:\n", (int)mSegs.size());
+ for (std::vector<Seg>::iterator iter = mSegs.begin();
+ iter < mSegs.end();
+ ++iter) {
+ printf(" %016llx %016llx %s\n",
+ (unsigned long long int)(*iter).lo,
+ (unsigned long long int)(*iter).hi,
+ (*iter).val ? "true" : "false");
+ }
+ printf(">>\n");
+ }
+
+ std::vector<Seg> mSegs;
+};
+
+
+////////////////////////////////////////////////////////////////
+// PriMap //
+////////////////////////////////////////////////////////////////
+
+class PriMap {
+ public:
+ explicit PriMap(void (*aLog)(const char*))
+ : mLog(aLog)
+ {}
+
+ ~PriMap() {
+ for (std::vector<SecMap*>::iterator iter = mSecMaps.begin();
+ iter != mSecMaps.end();
+ ++iter) {
+ delete *iter;
+ }
+ mSecMaps.clear();
+ }
+
+ // RUNS IN NO-MALLOC CONTEXT
+ pair<const RuleSet*, const vector<PfxInstr>*>
+ Lookup(uintptr_t ia)
+ {
+ SecMap* sm = FindSecMap(ia);
+ return pair<const RuleSet*, const vector<PfxInstr>*>
+ (sm ? sm->FindRuleSet(ia) : nullptr,
+ sm ? sm->GetPfxInstrs() : nullptr);
+ }
+
+ // Add a secondary map. No overlaps allowed w.r.t. existing
+ // secondary maps.
+ void AddSecMap(SecMap* aSecMap) {
+ // We can't add an empty SecMap to the PriMap. But that's OK
+ // since we'd never be able to find anything in it anyway.
+ if (aSecMap->IsEmpty()) {
+ return;
+ }
+
+ // Iterate through the SecMaps and find the right place for this
+ // one. At the same time, ensure that the in-order
+ // non-overlapping invariant is preserved (and, generally, holds).
+ // FIXME: this gives a cost that is O(N^2) in the total number of
+ // shared objects in the system. ToDo: better.
+ MOZ_ASSERT(aSecMap->mSummaryMinAddr <= aSecMap->mSummaryMaxAddr);
+
+ size_t num_secMaps = mSecMaps.size();
+ uintptr_t i;
+ for (i = 0; i < num_secMaps; ++i) {
+ SecMap* sm_i = mSecMaps[i];
+ MOZ_ASSERT(sm_i->mSummaryMinAddr <= sm_i->mSummaryMaxAddr);
+ if (aSecMap->mSummaryMinAddr < sm_i->mSummaryMaxAddr) {
+ // |aSecMap| needs to be inserted immediately before mSecMaps[i].
+ break;
+ }
+ }
+ MOZ_ASSERT(i <= num_secMaps);
+ if (i == num_secMaps) {
+ // It goes at the end.
+ mSecMaps.push_back(aSecMap);
+ } else {
+ std::vector<SecMap*>::iterator iter = mSecMaps.begin() + i;
+ mSecMaps.insert(iter, aSecMap);
+ }
+ char buf[100];
+ SprintfLiteral(buf, "AddSecMap: now have %d SecMaps\n",
+ (int)mSecMaps.size());
+ buf[sizeof(buf)-1] = 0;
+ mLog(buf);
+ }
+
+ // Remove and delete any SecMaps in the mapping, that intersect
+ // with the specified address range.
+ void RemoveSecMapsInRange(uintptr_t avma_min, uintptr_t avma_max) {
+ MOZ_ASSERT(avma_min <= avma_max);
+ size_t num_secMaps = mSecMaps.size();
+ if (num_secMaps > 0) {
+ intptr_t i;
+ // Iterate from end to start over the vector, so as to ensure
+ // that the special case where |avma_min| and |avma_max| denote
+ // the entire address space, can be completed in time proportional
+ // to the number of elements in the map.
+ for (i = (intptr_t)num_secMaps-1; i >= 0; i--) {
+ SecMap* sm_i = mSecMaps[i];
+ if (sm_i->mSummaryMaxAddr < avma_min ||
+ avma_max < sm_i->mSummaryMinAddr) {
+ // There's no overlap. Move on.
+ continue;
+ }
+ // We need to remove mSecMaps[i] and slide all those above it
+ // downwards to cover the hole.
+ mSecMaps.erase(mSecMaps.begin() + i);
+ delete sm_i;
+ }
+ }
+ }
+
+ // Return the number of currently contained SecMaps.
+ size_t CountSecMaps() {
+ return mSecMaps.size();
+ }
+
+ // Assess heuristically whether the given address is an instruction
+ // immediately following a call instruction.
+ // RUNS IN NO-MALLOC CONTEXT
+ bool MaybeIsReturnPoint(TaggedUWord aInstrAddr, SegArray* aSegArray) {
+ if (!aInstrAddr.Valid()) {
+ return false;
+ }
+
+ uintptr_t ia = aInstrAddr.Value();
+
+ // Assume that nobody would be crazy enough to put code in the
+ // first or last page.
+ if (ia < 4096 || ((uintptr_t)(-ia)) < 4096) {
+ return false;
+ }
+
+ // See if it falls inside a known r-x mapped area. Poking around
+ // outside such places risks segfaulting.
+ uintptr_t insns_min, insns_max;
+ bool b = aSegArray->getBoundingCodeSegment(&insns_min, &insns_max, ia);
+ if (!b) {
+ // no code (that we know about) at this address
+ return false;
+ }
+
+ // |ia| falls within an r-x range. So we can
+ // safely poke around in [insns_min, insns_max].
+
+#if defined(LUL_ARCH_x64) || defined(LUL_ARCH_x86)
+ // Is the previous instruction recognisably a CALL? This is
+ // common for the 32- and 64-bit versions, except for the
+ // simm32(%rip) case, which is 64-bit only.
+ //
+ // For all other cases, the 64 bit versions are either identical
+ // to the 32 bit versions, or have an optional extra leading REX.W
+ // byte (0x41). Since the extra 0x41 is optional we have to
+ // ignore it, with the convenient result that the same matching
+ // logic works for both 32- and 64-bit cases.
+
+ uint8_t* p = (uint8_t*)ia;
+# if defined(LUL_ARCH_x64)
+ // CALL simm32(%rip) == FF15 simm32
+ if (ia - 6 >= insns_min && p[-6] == 0xFF && p[-5] == 0x15) {
+ return true;
+ }
+# endif
+ // CALL rel32 == E8 rel32 (both 32- and 64-bit)
+ if (ia - 5 >= insns_min && p[-5] == 0xE8) {
+ return true;
+ }
+ // CALL *%eax .. CALL *%edi == FFD0 .. FFD7 (32-bit)
+ // CALL *%rax .. CALL *%rdi == FFD0 .. FFD7 (64-bit)
+ // CALL *%r8 .. CALL *%r15 == 41FFD0 .. 41FFD7 (64-bit)
+ if (ia - 2 >= insns_min &&
+ p[-2] == 0xFF && p[-1] >= 0xD0 && p[-1] <= 0xD7) {
+ return true;
+ }
+ // Almost all of the remaining cases that occur in practice are
+ // of the form CALL *simm8(reg) or CALL *simm32(reg).
+ //
+ // 64 bit cases:
+ //
+ // call *simm8(%rax) FF50 simm8
+ // call *simm8(%rcx) FF51 simm8
+ // call *simm8(%rdx) FF52 simm8
+ // call *simm8(%rbx) FF53 simm8
+ // call *simm8(%rsp) FF5424 simm8
+ // call *simm8(%rbp) FF55 simm8
+ // call *simm8(%rsi) FF56 simm8
+ // call *simm8(%rdi) FF57 simm8
+ //
+ // call *simm8(%r8) 41FF50 simm8
+ // call *simm8(%r9) 41FF51 simm8
+ // call *simm8(%r10) 41FF52 simm8
+ // call *simm8(%r11) 41FF53 simm8
+ // call *simm8(%r12) 41FF5424 simm8
+ // call *simm8(%r13) 41FF55 simm8
+ // call *simm8(%r14) 41FF56 simm8
+ // call *simm8(%r15) 41FF57 simm8
+ //
+ // call *simm32(%rax) FF90 simm32
+ // call *simm32(%rcx) FF91 simm32
+ // call *simm32(%rdx) FF92 simm32
+ // call *simm32(%rbx) FF93 simm32
+ // call *simm32(%rsp) FF9424 simm32
+ // call *simm32(%rbp) FF95 simm32
+ // call *simm32(%rsi) FF96 simm32
+ // call *simm32(%rdi) FF97 simm32
+ //
+ // call *simm32(%r8) 41FF90 simm32
+ // call *simm32(%r9) 41FF91 simm32
+ // call *simm32(%r10) 41FF92 simm32
+ // call *simm32(%r11) 41FF93 simm32
+ // call *simm32(%r12) 41FF9424 simm32
+ // call *simm32(%r13) 41FF95 simm32
+ // call *simm32(%r14) 41FF96 simm32
+ // call *simm32(%r15) 41FF97 simm32
+ //
+ // 32 bit cases:
+ //
+ // call *simm8(%eax) FF50 simm8
+ // call *simm8(%ecx) FF51 simm8
+ // call *simm8(%edx) FF52 simm8
+ // call *simm8(%ebx) FF53 simm8
+ // call *simm8(%esp) FF5424 simm8
+ // call *simm8(%ebp) FF55 simm8
+ // call *simm8(%esi) FF56 simm8
+ // call *simm8(%edi) FF57 simm8
+ //
+ // call *simm32(%eax) FF90 simm32
+ // call *simm32(%ecx) FF91 simm32
+ // call *simm32(%edx) FF92 simm32
+ // call *simm32(%ebx) FF93 simm32
+ // call *simm32(%esp) FF9424 simm32
+ // call *simm32(%ebp) FF95 simm32
+ // call *simm32(%esi) FF96 simm32
+ // call *simm32(%edi) FF97 simm32
+ if (ia - 3 >= insns_min &&
+ p[-3] == 0xFF &&
+ (p[-2] >= 0x50 && p[-2] <= 0x57 && p[-2] != 0x54)) {
+ // imm8 case, not including %esp/%rsp
+ return true;
+ }
+ if (ia - 4 >= insns_min &&
+ p[-4] == 0xFF && p[-3] == 0x54 && p[-2] == 0x24) {
+ // imm8 case for %esp/%rsp
+ return true;
+ }
+ if (ia - 6 >= insns_min &&
+ p[-6] == 0xFF &&
+ (p[-5] >= 0x90 && p[-5] <= 0x97 && p[-5] != 0x94)) {
+ // imm32 case, not including %esp/%rsp
+ return true;
+ }
+ if (ia - 7 >= insns_min &&
+ p[-7] == 0xFF && p[-6] == 0x94 && p[-5] == 0x24) {
+ // imm32 case for %esp/%rsp
+ return true;
+ }
+
+#elif defined(LUL_ARCH_arm)
+ if (ia & 1) {
+ uint16_t w0 = 0, w1 = 0;
+ // The return address has its lowest bit set, indicating a return
+ // to Thumb code.
+ ia &= ~(uintptr_t)1;
+ if (ia - 2 >= insns_min && ia - 1 <= insns_max) {
+ w1 = *(uint16_t*)(ia - 2);
+ }
+ if (ia - 4 >= insns_min && ia - 1 <= insns_max) {
+ w0 = *(uint16_t*)(ia - 4);
+ }
+ // Is it a 32-bit Thumb call insn?
+ // BL simm26 (Encoding T1)
+ if ((w0 & 0xF800) == 0xF000 && (w1 & 0xC000) == 0xC000) {
+ return true;
+ }
+ // BLX simm26 (Encoding T2)
+ if ((w0 & 0xF800) == 0xF000 && (w1 & 0xC000) == 0xC000) {
+ return true;
+ }
+ // Other possible cases:
+ // (BLX Rm, Encoding T1).
+ // BLX Rm (encoding T1, 16 bit, inspect w1 and ignore w0.)
+ // 0100 0111 1 Rm 000
+ } else {
+ // Returning to ARM code.
+ uint32_t a0 = 0;
+ if ((ia & 3) == 0 && ia - 4 >= insns_min && ia - 1 <= insns_max) {
+ a0 = *(uint32_t*)(ia - 4);
+ }
+ // Leading E forces unconditional only -- fix. It could be
+ // anything except F, which is the deprecated NV code.
+ // BL simm26 (Encoding A1)
+ if ((a0 & 0xFF000000) == 0xEB000000) {
+ return true;
+ }
+ // Other possible cases:
+ // BLX simm26 (Encoding A2)
+ //if ((a0 & 0xFE000000) == 0xFA000000)
+ // return true;
+ // BLX (register) (A1): BLX <c> <Rm>
+ // cond 0001 0010 1111 1111 1111 0011 Rm
+ // again, cond can be anything except NV (0xF)
+ }
+
+#else
+# error "Unsupported arch"
+#endif
+
+ // Not an insn we recognise.
+ return false;
+ }
+
+ private:
+ // RUNS IN NO-MALLOC CONTEXT
+ SecMap* FindSecMap(uintptr_t ia) {
+ // Binary search mSecMaps to find one that brackets |ia|.
+ // lo and hi need to be signed, else the loop termination tests
+ // don't work properly.
+ long int lo = 0;
+ long int hi = (long int)mSecMaps.size() - 1;
+ while (true) {
+ // current unsearched space is from lo to hi, inclusive.
+ if (lo > hi) {
+ // not found
+ return nullptr;
+ }
+ long int mid = lo + ((hi - lo) / 2);
+ SecMap* mid_secMap = mSecMaps[mid];
+ uintptr_t mid_minAddr = mid_secMap->mSummaryMinAddr;
+ uintptr_t mid_maxAddr = mid_secMap->mSummaryMaxAddr;
+ if (ia < mid_minAddr) { hi = mid-1; continue; }
+ if (ia > mid_maxAddr) { lo = mid+1; continue; }
+ MOZ_ASSERT(mid_minAddr <= ia && ia <= mid_maxAddr);
+ return mid_secMap;
+ }
+ // NOTREACHED
+ }
+
+ private:
+ // sorted array of per-object ranges, non overlapping, non empty
+ std::vector<SecMap*> mSecMaps;
+
+ // a logging sink, for debugging.
+ void (*mLog)(const char*);
+};
+
+
+////////////////////////////////////////////////////////////////
+// LUL //
+////////////////////////////////////////////////////////////////
+
+#define LUL_LOG(_str) \
+ do { \
+ char buf[200]; \
+ SprintfLiteral(buf, \
+ "LUL: pid %d tid %d lul-obj %p: %s", \
+ getpid(), gettid(), this, (_str)); \
+ buf[sizeof(buf)-1] = 0; \
+ mLog(buf); \
+ } while (0)
+
+LUL::LUL(void (*aLog)(const char*))
+ : mLog(aLog)
+ , mAdminMode(true)
+ , mAdminThreadId(gettid())
+ , mPriMap(new PriMap(aLog))
+ , mSegArray(new SegArray())
+ , mUSU(new UniqueStringUniverse())
+{
+ LUL_LOG("LUL::LUL: Created object");
+}
+
+
+LUL::~LUL()
+{
+ LUL_LOG("LUL::~LUL: Destroyed object");
+ delete mPriMap;
+ delete mSegArray;
+ mLog = nullptr;
+ delete mUSU;
+}
+
+
+void
+LUL::MaybeShowStats()
+{
+ // This is racey in the sense that it can't guarantee that
+ // n_new == n_new_Context + n_new_CFI + n_new_Scanned
+ // if it should happen that mStats is updated by some other thread
+ // in between computation of n_new and n_new_{Context,CFI,Scanned}.
+ // But it's just stats printing, so we don't really care.
+ uint32_t n_new = mStats - mStatsPrevious;
+ if (n_new >= 5000) {
+ uint32_t n_new_Context = mStats.mContext - mStatsPrevious.mContext;
+ uint32_t n_new_CFI = mStats.mCFI - mStatsPrevious.mCFI;
+ uint32_t n_new_Scanned = mStats.mScanned - mStatsPrevious.mScanned;
+ mStatsPrevious = mStats;
+ char buf[200];
+ SprintfLiteral(buf,
+ "LUL frame stats: TOTAL %5u"
+ " CTX %4u CFI %4u SCAN %4u",
+ n_new, n_new_Context, n_new_CFI, n_new_Scanned);
+ buf[sizeof(buf)-1] = 0;
+ mLog(buf);
+ }
+}
+
+
+void
+LUL::EnableUnwinding()
+{
+ LUL_LOG("LUL::EnableUnwinding");
+ // Don't assert for Admin mode here. That is, tolerate a call here
+ // if we are already in Unwinding mode.
+ MOZ_ASSERT(gettid() == mAdminThreadId);
+
+ mAdminMode = false;
+}
+
+
+void
+LUL::NotifyAfterMap(uintptr_t aRXavma, size_t aSize,
+ const char* aFileName, const void* aMappedImage)
+{
+ MOZ_ASSERT(mAdminMode);
+ MOZ_ASSERT(gettid() == mAdminThreadId);
+
+ mLog(":\n");
+ char buf[200];
+ SprintfLiteral(buf, "NotifyMap %llx %llu %s\n",
+ (unsigned long long int)aRXavma, (unsigned long long int)aSize,
+ aFileName);
+ buf[sizeof(buf)-1] = 0;
+ mLog(buf);
+
+ // Ignore obviously-stupid notifications.
+ if (aSize > 0) {
+
+ // Here's a new mapping, for this object.
+ SecMap* smap = new SecMap(mLog);
+
+ // Read CFI or EXIDX unwind data into |smap|.
+ if (!aMappedImage) {
+ (void)lul::ReadSymbolData(
+ string(aFileName), std::vector<string>(), smap,
+ (void*)aRXavma, aSize, mUSU, mLog);
+ } else {
+ (void)lul::ReadSymbolDataInternal(
+ (const uint8_t*)aMappedImage,
+ string(aFileName), std::vector<string>(), smap,
+ (void*)aRXavma, aSize, mUSU, mLog);
+ }
+
+ mLog("NotifyMap .. preparing entries\n");
+
+ smap->PrepareRuleSets(aRXavma, aSize);
+
+ SprintfLiteral(buf,
+ "NotifyMap got %lld entries\n", (long long int)smap->Size());
+ buf[sizeof(buf)-1] = 0;
+ mLog(buf);
+
+ // Add it to the primary map (the top level set of mapped objects).
+ mPriMap->AddSecMap(smap);
+
+ // Tell the segment array about the mapping, so that the stack
+ // scan and __kernel_syscall mechanisms know where valid code is.
+ mSegArray->add(aRXavma, aRXavma + aSize - 1, true);
+ }
+}
+
+
+void
+LUL::NotifyExecutableArea(uintptr_t aRXavma, size_t aSize)
+{
+ MOZ_ASSERT(mAdminMode);
+ MOZ_ASSERT(gettid() == mAdminThreadId);
+
+ mLog(":\n");
+ char buf[200];
+ SprintfLiteral(buf, "NotifyExecutableArea %llx %llu\n",
+ (unsigned long long int)aRXavma, (unsigned long long int)aSize);
+ buf[sizeof(buf)-1] = 0;
+ mLog(buf);
+
+ // Ignore obviously-stupid notifications.
+ if (aSize > 0) {
+ // Tell the segment array about the mapping, so that the stack
+ // scan and __kernel_syscall mechanisms know where valid code is.
+ mSegArray->add(aRXavma, aRXavma + aSize - 1, true);
+ }
+}
+
+
+void
+LUL::NotifyBeforeUnmap(uintptr_t aRXavmaMin, uintptr_t aRXavmaMax)
+{
+ MOZ_ASSERT(mAdminMode);
+ MOZ_ASSERT(gettid() == mAdminThreadId);
+
+ mLog(":\n");
+ char buf[100];
+ SprintfLiteral(buf, "NotifyUnmap %016llx-%016llx\n",
+ (unsigned long long int)aRXavmaMin,
+ (unsigned long long int)aRXavmaMax);
+ buf[sizeof(buf)-1] = 0;
+ mLog(buf);
+
+ MOZ_ASSERT(aRXavmaMin <= aRXavmaMax);
+
+ // Remove from the primary map, any secondary maps that intersect
+ // with the address range. Also delete the secondary maps.
+ mPriMap->RemoveSecMapsInRange(aRXavmaMin, aRXavmaMax);
+
+ // Tell the segment array that the address range no longer
+ // contains valid code.
+ mSegArray->add(aRXavmaMin, aRXavmaMax, false);
+
+ SprintfLiteral(buf, "NotifyUnmap: now have %d SecMaps\n",
+ (int)mPriMap->CountSecMaps());
+ buf[sizeof(buf)-1] = 0;
+ mLog(buf);
+}
+
+
+size_t
+LUL::CountMappings()
+{
+ MOZ_ASSERT(mAdminMode);
+ MOZ_ASSERT(gettid() == mAdminThreadId);
+
+ return mPriMap->CountSecMaps();
+}
+
+
+// RUNS IN NO-MALLOC CONTEXT
+static
+TaggedUWord DerefTUW(TaggedUWord aAddr, const StackImage* aStackImg)
+{
+ if (!aAddr.Valid()) {
+ return TaggedUWord();
+ }
+
+ // Lower limit check. |aAddr.Value()| is the lowest requested address
+ // and |aStackImg->mStartAvma| is the lowest address we actually have,
+ // so the comparison is straightforward.
+ if (aAddr.Value() < aStackImg->mStartAvma) {
+ return TaggedUWord();
+ }
+
+ // Upper limit check. We must compute the highest requested address
+ // and the highest address we actually have, but being careful to
+ // avoid overflow. In particular if |aAddr| is 0xFFF...FFF or the
+ // 3/7 values below that, then we will get overflow. See bug #1245477.
+ typedef CheckedInt<uintptr_t> CheckedUWord;
+ CheckedUWord highest_requested_plus_one
+ = CheckedUWord(aAddr.Value()) + CheckedUWord(sizeof(uintptr_t));
+ CheckedUWord highest_available_plus_one
+ = CheckedUWord(aStackImg->mStartAvma) + CheckedUWord(aStackImg->mLen);
+ if (!highest_requested_plus_one.isValid() // overflow?
+ || !highest_available_plus_one.isValid() // overflow?
+ || (highest_requested_plus_one.value()
+ > highest_available_plus_one.value())) { // in range?
+ return TaggedUWord();
+ }
+
+ return TaggedUWord(*(uintptr_t*)(aStackImg->mContents + aAddr.Value()
+ - aStackImg->mStartAvma));
+}
+
+// RUNS IN NO-MALLOC CONTEXT
+static
+TaggedUWord EvaluateReg(int16_t aReg, const UnwindRegs* aOldRegs,
+ TaggedUWord aCFA)
+{
+ switch (aReg) {
+ case DW_REG_CFA: return aCFA;
+#if defined(LUL_ARCH_x64) || defined(LUL_ARCH_x86)
+ case DW_REG_INTEL_XBP: return aOldRegs->xbp;
+ case DW_REG_INTEL_XSP: return aOldRegs->xsp;
+ case DW_REG_INTEL_XIP: return aOldRegs->xip;
+#elif defined(LUL_ARCH_arm)
+ case DW_REG_ARM_R7: return aOldRegs->r7;
+ case DW_REG_ARM_R11: return aOldRegs->r11;
+ case DW_REG_ARM_R12: return aOldRegs->r12;
+ case DW_REG_ARM_R13: return aOldRegs->r13;
+ case DW_REG_ARM_R14: return aOldRegs->r14;
+ case DW_REG_ARM_R15: return aOldRegs->r15;
+#else
+# error "Unsupported arch"
+#endif
+ default: MOZ_ASSERT(0); return TaggedUWord();
+ }
+}
+
+// RUNS IN NO-MALLOC CONTEXT
+// See prototype for comment.
+TaggedUWord EvaluatePfxExpr(int32_t start,
+ const UnwindRegs* aOldRegs,
+ TaggedUWord aCFA, const StackImage* aStackImg,
+ const vector<PfxInstr>& aPfxInstrs)
+{
+ // A small evaluation stack, and a stack pointer, which points to
+ // the highest numbered in-use element.
+ const int N_STACK = 10;
+ TaggedUWord stack[N_STACK];
+ int stackPointer = -1;
+ for (int i = 0; i < N_STACK; i++)
+ stack[i] = TaggedUWord();
+
+# define PUSH(_tuw) \
+ do { \
+ if (stackPointer >= N_STACK-1) goto fail; /* overflow */ \
+ stack[++stackPointer] = (_tuw); \
+ } while (0)
+
+# define POP(_lval) \
+ do { \
+ if (stackPointer < 0) goto fail; /* underflow */ \
+ _lval = stack[stackPointer--]; \
+ } while (0)
+
+ // Cursor in the instruction sequence.
+ size_t curr = start + 1;
+
+ // Check the start point is sane.
+ size_t nInstrs = aPfxInstrs.size();
+ if (start < 0 || (size_t)start >= nInstrs)
+ goto fail;
+
+ {
+ // The instruction sequence must start with PX_Start. If not,
+ // something is seriously wrong.
+ PfxInstr first = aPfxInstrs[start];
+ if (first.mOpcode != PX_Start)
+ goto fail;
+
+ // Push the CFA on the stack to start with (or not), as required by
+ // the original DW_OP_*expression* CFI.
+ if (first.mOperand != 0)
+ PUSH(aCFA);
+ }
+
+ while (true) {
+ if (curr >= nInstrs)
+ goto fail; // ran off the end of the sequence
+
+ PfxInstr pfxi = aPfxInstrs[curr++];
+ if (pfxi.mOpcode == PX_End)
+ break; // we're done
+
+ switch (pfxi.mOpcode) {
+ case PX_Start:
+ // This should appear only at the start of the sequence.
+ goto fail;
+ case PX_End:
+ // We just took care of that, so we shouldn't see it again.
+ MOZ_ASSERT(0);
+ goto fail;
+ case PX_SImm32:
+ PUSH(TaggedUWord((intptr_t)pfxi.mOperand));
+ break;
+ case PX_DwReg: {
+ DW_REG_NUMBER reg = (DW_REG_NUMBER)pfxi.mOperand;
+ MOZ_ASSERT(reg != DW_REG_CFA);
+ PUSH(EvaluateReg(reg, aOldRegs, aCFA));
+ break;
+ }
+ case PX_Deref: {
+ TaggedUWord addr;
+ POP(addr);
+ PUSH(DerefTUW(addr, aStackImg));
+ break;
+ }
+ case PX_Add: {
+ TaggedUWord x, y;
+ POP(x); POP(y); PUSH(y + x);
+ break;
+ }
+ case PX_Sub: {
+ TaggedUWord x, y;
+ POP(x); POP(y); PUSH(y - x);
+ break;
+ }
+ case PX_And: {
+ TaggedUWord x, y;
+ POP(x); POP(y); PUSH(y & x);
+ break;
+ }
+ case PX_Or: {
+ TaggedUWord x, y;
+ POP(x); POP(y); PUSH(y | x);
+ break;
+ }
+ case PX_CmpGES: {
+ TaggedUWord x, y;
+ POP(x); POP(y); PUSH(y.CmpGEs(x));
+ break;
+ }
+ case PX_Shl: {
+ TaggedUWord x, y;
+ POP(x); POP(y); PUSH(y << x);
+ break;
+ }
+ default:
+ MOZ_ASSERT(0);
+ goto fail;
+ }
+ } // while (true)
+
+ // Evaluation finished. The top value on the stack is the result.
+ if (stackPointer >= 0) {
+ return stack[stackPointer];
+ }
+ // Else fall through
+
+ fail:
+ return TaggedUWord();
+
+# undef PUSH
+# undef POP
+}
+
+// RUNS IN NO-MALLOC CONTEXT
+TaggedUWord LExpr::EvaluateExpr(const UnwindRegs* aOldRegs,
+ TaggedUWord aCFA, const StackImage* aStackImg,
+ const vector<PfxInstr>* aPfxInstrs) const
+{
+ switch (mHow) {
+ case UNKNOWN:
+ return TaggedUWord();
+ case NODEREF: {
+ TaggedUWord tuw = EvaluateReg(mReg, aOldRegs, aCFA);
+ tuw = tuw + TaggedUWord((intptr_t)mOffset);
+ return tuw;
+ }
+ case DEREF: {
+ TaggedUWord tuw = EvaluateReg(mReg, aOldRegs, aCFA);
+ tuw = tuw + TaggedUWord((intptr_t)mOffset);
+ return DerefTUW(tuw, aStackImg);
+ }
+ case PFXEXPR: {
+ MOZ_ASSERT(aPfxInstrs);
+ if (!aPfxInstrs) {
+ return TaggedUWord();
+ }
+ return EvaluatePfxExpr(mOffset, aOldRegs, aCFA, aStackImg, *aPfxInstrs);
+ }
+ default:
+ MOZ_ASSERT(0);
+ return TaggedUWord();
+ }
+}
+
+// RUNS IN NO-MALLOC CONTEXT
+static
+void UseRuleSet(/*MOD*/UnwindRegs* aRegs,
+ const StackImage* aStackImg, const RuleSet* aRS,
+ const vector<PfxInstr>* aPfxInstrs)
+{
+ // Take a copy of regs, since we'll need to refer to the old values
+ // whilst computing the new ones.
+ UnwindRegs old_regs = *aRegs;
+
+ // Mark all the current register values as invalid, so that the
+ // caller can see, on our return, which ones have been computed
+ // anew. If we don't even manage to compute a new PC value, then
+ // the caller will have to abandon the unwind.
+ // FIXME: Create and use instead: aRegs->SetAllInvalid();
+#if defined(LUL_ARCH_x64) || defined(LUL_ARCH_x86)
+ aRegs->xbp = TaggedUWord();
+ aRegs->xsp = TaggedUWord();
+ aRegs->xip = TaggedUWord();
+#elif defined(LUL_ARCH_arm)
+ aRegs->r7 = TaggedUWord();
+ aRegs->r11 = TaggedUWord();
+ aRegs->r12 = TaggedUWord();
+ aRegs->r13 = TaggedUWord();
+ aRegs->r14 = TaggedUWord();
+ aRegs->r15 = TaggedUWord();
+#else
+# error "Unsupported arch"
+#endif
+
+ // This is generally useful.
+ const TaggedUWord inval = TaggedUWord();
+
+ // First, compute the CFA.
+ TaggedUWord cfa
+ = aRS->mCfaExpr.EvaluateExpr(&old_regs,
+ inval/*old cfa*/, aStackImg, aPfxInstrs);
+
+ // If we didn't manage to compute the CFA, well .. that's ungood,
+ // but keep going anyway. It'll be OK provided none of the register
+ // value rules mention the CFA. In any case, compute the new values
+ // for each register that we're tracking.
+
+#if defined(LUL_ARCH_x64) || defined(LUL_ARCH_x86)
+ aRegs->xbp
+ = aRS->mXbpExpr.EvaluateExpr(&old_regs, cfa, aStackImg, aPfxInstrs);
+ aRegs->xsp
+ = aRS->mXspExpr.EvaluateExpr(&old_regs, cfa, aStackImg, aPfxInstrs);
+ aRegs->xip
+ = aRS->mXipExpr.EvaluateExpr(&old_regs, cfa, aStackImg, aPfxInstrs);
+#elif defined(LUL_ARCH_arm)
+ aRegs->r7
+ = aRS->mR7expr .EvaluateExpr(&old_regs, cfa, aStackImg, aPfxInstrs);
+ aRegs->r11
+ = aRS->mR11expr.EvaluateExpr(&old_regs, cfa, aStackImg, aPfxInstrs);
+ aRegs->r12
+ = aRS->mR12expr.EvaluateExpr(&old_regs, cfa, aStackImg, aPfxInstrs);
+ aRegs->r13
+ = aRS->mR13expr.EvaluateExpr(&old_regs, cfa, aStackImg, aPfxInstrs);
+ aRegs->r14
+ = aRS->mR14expr.EvaluateExpr(&old_regs, cfa, aStackImg, aPfxInstrs);
+ aRegs->r15
+ = aRS->mR15expr.EvaluateExpr(&old_regs, cfa, aStackImg, aPfxInstrs);
+#else
+# error "Unsupported arch"
+#endif
+
+ // We're done. Any regs for which we didn't manage to compute a
+ // new value will now be marked as invalid.
+}
+
+// RUNS IN NO-MALLOC CONTEXT
+void
+LUL::Unwind(/*OUT*/uintptr_t* aFramePCs,
+ /*OUT*/uintptr_t* aFrameSPs,
+ /*OUT*/size_t* aFramesUsed,
+ /*OUT*/size_t* aScannedFramesAcquired,
+ size_t aFramesAvail,
+ size_t aScannedFramesAllowed,
+ UnwindRegs* aStartRegs, StackImage* aStackImg)
+{
+ MOZ_ASSERT(!mAdminMode);
+
+ /////////////////////////////////////////////////////////
+ // BEGIN UNWIND
+
+ *aFramesUsed = 0;
+
+ UnwindRegs regs = *aStartRegs;
+ TaggedUWord last_valid_sp = TaggedUWord();
+
+ // Stack-scan control
+ unsigned int n_scanned_frames = 0; // # s-s frames recovered so far
+ static const int NUM_SCANNED_WORDS = 50; // max allowed scan length
+
+ while (true) {
+
+ if (DEBUG_MAIN) {
+ char buf[300];
+ mLog("\n");
+#if defined(LUL_ARCH_x64) || defined(LUL_ARCH_x86)
+ SprintfLiteral(buf,
+ "LoopTop: rip %d/%llx rsp %d/%llx rbp %d/%llx\n",
+ (int)regs.xip.Valid(), (unsigned long long int)regs.xip.Value(),
+ (int)regs.xsp.Valid(), (unsigned long long int)regs.xsp.Value(),
+ (int)regs.xbp.Valid(), (unsigned long long int)regs.xbp.Value());
+ buf[sizeof(buf)-1] = 0;
+ mLog(buf);
+#elif defined(LUL_ARCH_arm)
+ SprintfLiteral(buf,
+ "LoopTop: r15 %d/%llx r7 %d/%llx r11 %d/%llx"
+ " r12 %d/%llx r13 %d/%llx r14 %d/%llx\n",
+ (int)regs.r15.Valid(), (unsigned long long int)regs.r15.Value(),
+ (int)regs.r7.Valid(), (unsigned long long int)regs.r7.Value(),
+ (int)regs.r11.Valid(), (unsigned long long int)regs.r11.Value(),
+ (int)regs.r12.Valid(), (unsigned long long int)regs.r12.Value(),
+ (int)regs.r13.Valid(), (unsigned long long int)regs.r13.Value(),
+ (int)regs.r14.Valid(), (unsigned long long int)regs.r14.Value());
+ buf[sizeof(buf)-1] = 0;
+ mLog(buf);
+#else
+# error "Unsupported arch"
+#endif
+ }
+
+#if defined(LUL_ARCH_x64) || defined(LUL_ARCH_x86)
+ TaggedUWord ia = regs.xip;
+ TaggedUWord sp = regs.xsp;
+#elif defined(LUL_ARCH_arm)
+ TaggedUWord ia = (*aFramesUsed == 0 ? regs.r15 : regs.r14);
+ TaggedUWord sp = regs.r13;
+#else
+# error "Unsupported arch"
+#endif
+
+ if (*aFramesUsed >= aFramesAvail) {
+ break;
+ }
+
+ // If we don't have a valid value for the PC, give up.
+ if (!ia.Valid()) {
+ break;
+ }
+
+ // If this is the innermost frame, record the SP value, which
+ // presumably is valid. If this isn't the innermost frame, and we
+ // have a valid SP value, check that its SP value isn't less that
+ // the one we've seen so far, so as to catch potential SP value
+ // cycles.
+ if (*aFramesUsed == 0) {
+ last_valid_sp = sp;
+ } else {
+ MOZ_ASSERT(last_valid_sp.Valid());
+ if (sp.Valid()) {
+ if (sp.Value() < last_valid_sp.Value()) {
+ // Hmm, SP going in the wrong direction. Let's stop.
+ break;
+ }
+ // Remember where we got to.
+ last_valid_sp = sp;
+ }
+ }
+
+ // For the innermost frame, the IA value is what we need. For all
+ // other frames, it's actually the return address, so back up one
+ // byte so as to get it into the calling instruction.
+ aFramePCs[*aFramesUsed] = ia.Value() - (*aFramesUsed == 0 ? 0 : 1);
+ aFrameSPs[*aFramesUsed] = sp.Valid() ? sp.Value() : 0;
+ (*aFramesUsed)++;
+
+ // Find the RuleSet for the current IA, if any. This will also
+ // query the backing (secondary) maps if it isn't found in the
+ // thread-local cache.
+
+ // If this isn't the innermost frame, back up into the calling insn.
+ if (*aFramesUsed > 1) {
+ ia = ia + TaggedUWord((uintptr_t)(-1));
+ }
+
+ pair<const RuleSet*, const vector<PfxInstr>*> ruleset_and_pfxinstrs
+ = mPriMap->Lookup(ia.Value());
+ const RuleSet* ruleset = ruleset_and_pfxinstrs.first;
+ const vector<PfxInstr>* pfxinstrs = ruleset_and_pfxinstrs.second;
+
+ if (DEBUG_MAIN) {
+ char buf[100];
+ SprintfLiteral(buf, "ruleset for 0x%llx = %p\n",
+ (unsigned long long int)ia.Value(), ruleset);
+ buf[sizeof(buf)-1] = 0;
+ mLog(buf);
+ }
+
+ /////////////////////////////////////////////
+ ////
+ // On 32 bit x86-linux, syscalls are often done via the VDSO
+ // function __kernel_vsyscall, which doesn't have a corresponding
+ // object that we can read debuginfo from. That effectively kills
+ // off all stack traces for threads blocked in syscalls. Hence
+ // special-case by looking at the code surrounding the program
+ // counter.
+ //
+ // 0xf7757420 <__kernel_vsyscall+0>: push %ecx
+ // 0xf7757421 <__kernel_vsyscall+1>: push %edx
+ // 0xf7757422 <__kernel_vsyscall+2>: push %ebp
+ // 0xf7757423 <__kernel_vsyscall+3>: mov %esp,%ebp
+ // 0xf7757425 <__kernel_vsyscall+5>: sysenter
+ // 0xf7757427 <__kernel_vsyscall+7>: nop
+ // 0xf7757428 <__kernel_vsyscall+8>: nop
+ // 0xf7757429 <__kernel_vsyscall+9>: nop
+ // 0xf775742a <__kernel_vsyscall+10>: nop
+ // 0xf775742b <__kernel_vsyscall+11>: nop
+ // 0xf775742c <__kernel_vsyscall+12>: nop
+ // 0xf775742d <__kernel_vsyscall+13>: nop
+ // 0xf775742e <__kernel_vsyscall+14>: int $0x80
+ // 0xf7757430 <__kernel_vsyscall+16>: pop %ebp
+ // 0xf7757431 <__kernel_vsyscall+17>: pop %edx
+ // 0xf7757432 <__kernel_vsyscall+18>: pop %ecx
+ // 0xf7757433 <__kernel_vsyscall+19>: ret
+ //
+ // In cases where the sampled thread is blocked in a syscall, its
+ // program counter will point at "pop %ebp". Hence we look for
+ // the sequence "int $0x80; pop %ebp; pop %edx; pop %ecx; ret", and
+ // the corresponding register-recovery actions are:
+ // new_ebp = *(old_esp + 0)
+ // new eip = *(old_esp + 12)
+ // new_esp = old_esp + 16
+ //
+ // It may also be the case that the program counter points two
+ // nops before the "int $0x80", viz, is __kernel_vsyscall+12, in
+ // the case where the syscall has been restarted but the thread
+ // hasn't been rescheduled. The code below doesn't handle that;
+ // it could easily be made to.
+ //
+#if defined(LUL_PLAT_x86_android) || defined(LUL_PLAT_x86_linux)
+ if (!ruleset && *aFramesUsed == 1 && ia.Valid() && sp.Valid()) {
+ uintptr_t insns_min, insns_max;
+ uintptr_t eip = ia.Value();
+ bool b = mSegArray->getBoundingCodeSegment(&insns_min, &insns_max, eip);
+ if (b && eip - 2 >= insns_min && eip + 3 <= insns_max) {
+ uint8_t* eipC = (uint8_t*)eip;
+ if (eipC[-2] == 0xCD && eipC[-1] == 0x80 && eipC[0] == 0x5D &&
+ eipC[1] == 0x5A && eipC[2] == 0x59 && eipC[3] == 0xC3) {
+ TaggedUWord sp_plus_0 = sp;
+ TaggedUWord sp_plus_12 = sp;
+ TaggedUWord sp_plus_16 = sp;
+ sp_plus_12 = sp_plus_12 + TaggedUWord(12);
+ sp_plus_16 = sp_plus_16 + TaggedUWord(16);
+ TaggedUWord new_ebp = DerefTUW(sp_plus_0, aStackImg);
+ TaggedUWord new_eip = DerefTUW(sp_plus_12, aStackImg);
+ TaggedUWord new_esp = sp_plus_16;
+ if (new_ebp.Valid() && new_eip.Valid() && new_esp.Valid()) {
+ regs.xbp = new_ebp;
+ regs.xip = new_eip;
+ regs.xsp = new_esp;
+ continue;
+ }
+ }
+ }
+ }
+#endif
+ ////
+ /////////////////////////////////////////////
+
+ // So, do we have a ruleset for this address? If so, use it now.
+ if (ruleset) {
+
+ if (DEBUG_MAIN) {
+ ruleset->Print(mLog); mLog("\n");
+ }
+ // Use the RuleSet to compute the registers for the previous
+ // frame. |regs| is modified in-place.
+ UseRuleSet(&regs, aStackImg, ruleset, pfxinstrs);
+
+ } else {
+
+ // There's no RuleSet for the specified address, so see if
+ // it's possible to get anywhere by stack-scanning.
+
+ // Use stack scanning frugally.
+ if (n_scanned_frames++ >= aScannedFramesAllowed) {
+ break;
+ }
+
+ // We can't scan the stack without a valid, aligned stack pointer.
+ if (!sp.IsAligned()) {
+ break;
+ }
+
+ bool scan_succeeded = false;
+ for (int i = 0; i < NUM_SCANNED_WORDS; ++i) {
+ TaggedUWord aWord = DerefTUW(sp, aStackImg);
+ // aWord is something we fished off the stack. It should be
+ // valid, unless we overran the stack bounds.
+ if (!aWord.Valid()) {
+ break;
+ }
+
+ // Now, does aWord point inside a text section and immediately
+ // after something that looks like a call instruction?
+ if (mPriMap->MaybeIsReturnPoint(aWord, mSegArray)) {
+ // Yes it does. Update the unwound registers heuristically,
+ // using the same schemes as Breakpad does.
+ scan_succeeded = true;
+ (*aScannedFramesAcquired)++;
+
+#if defined(LUL_ARCH_x64) || defined(LUL_ARCH_x86)
+ // The same logic applies for the 32- and 64-bit cases.
+ // Register names of the form xsp etc refer to (eg) esp in
+ // the 32-bit case and rsp in the 64-bit case.
+# if defined(LUL_ARCH_x64)
+ const int wordSize = 8;
+# else
+ const int wordSize = 4;
+# endif
+ // The return address -- at XSP -- will have been pushed by
+ // the CALL instruction. So the caller's XSP value
+ // immediately before and after that CALL instruction is the
+ // word above XSP.
+ regs.xsp = sp + TaggedUWord(wordSize);
+
+ // aWord points at the return point, so back up one byte
+ // to put it in the calling instruction.
+ regs.xip = aWord + TaggedUWord((uintptr_t)(-1));
+
+ // Computing a new value from the frame pointer is more tricky.
+ if (regs.xbp.Valid() &&
+ sp.Valid() && regs.xbp.Value() == sp.Value() - wordSize) {
+ // One possibility is that the callee begins with the standard
+ // preamble "push %xbp; mov %xsp, %xbp". In which case, the
+ // (1) caller's XBP value will be at the word below XSP, and
+ // (2) the current (callee's) XBP will point at that word:
+ regs.xbp = DerefTUW(regs.xbp, aStackImg);
+ } else if (regs.xbp.Valid() &&
+ sp.Valid() && regs.xbp.Value() >= sp.Value() + wordSize) {
+ // If that didn't work out, maybe the callee didn't change
+ // XBP, so it still holds the caller's value. For that to
+ // be plausible, XBP will need to have a value at least
+ // higher than XSP since that holds the purported return
+ // address. In which case do nothing, since XBP already
+ // holds the "right" value.
+ } else {
+ // Mark XBP as invalid, so that subsequent unwind iterations
+ // don't assume it holds valid data.
+ regs.xbp = TaggedUWord();
+ }
+
+ // Move on to the next word up the stack
+ sp = sp + TaggedUWord(wordSize);
+
+#elif defined(LUL_ARCH_arm)
+ // Set all registers to be undefined, except for SP(R13) and
+ // PC(R15).
+
+ // aWord points either at the return point, if returning to
+ // ARM code, or one insn past the return point if returning
+ // to Thumb code. In both cases, aWord-2 is guaranteed to
+ // fall within the calling instruction.
+ regs.r15 = aWord + TaggedUWord((uintptr_t)(-2));
+
+ // Make SP be the word above the location where the return
+ // address was found.
+ regs.r13 = sp + TaggedUWord(4);
+
+ // All other regs are undefined.
+ regs.r7 = regs.r11 = regs.r12 = regs.r14 = TaggedUWord();
+
+ // Move on to the next word up the stack
+ sp = sp + TaggedUWord(4);
+
+#else
+# error "Unknown plat"
+#endif
+
+ break;
+ }
+
+ } // for (int i = 0; i < NUM_SCANNED_WORDS; i++)
+
+ // We tried to make progress by scanning the stack, but failed.
+ // So give up -- fall out of the top level unwind loop.
+ if (!scan_succeeded) {
+ break;
+ }
+ }
+
+ } // top level unwind loop
+
+ // END UNWIND
+ /////////////////////////////////////////////////////////
+}
+
+
+////////////////////////////////////////////////////////////////
+// LUL Unit Testing //
+////////////////////////////////////////////////////////////////
+
+static const int LUL_UNIT_TEST_STACK_SIZE = 16384;
+
+// This function is innermost in the test call sequence. It uses LUL
+// to unwind, and compares the result with the sequence specified in
+// the director string. These need to agree in order for the test to
+// pass. In order not to screw up the results, this function needs
+// to have a not-very big stack frame, since we're only presenting
+// the innermost LUL_UNIT_TEST_STACK_SIZE bytes of stack to LUL, and
+// that chunk unavoidably includes the frame for this function.
+//
+// This function must not be inlined into its callers. Doing so will
+// cause the expected-vs-actual backtrace consistency checking to
+// fail. Prints summary results to |aLUL|'s logging sink and also
+// returns a boolean indicating whether or not the test passed.
+static __attribute__((noinline))
+bool GetAndCheckStackTrace(LUL* aLUL, const char* dstring)
+{
+ // Get hold of the current unwind-start registers.
+ UnwindRegs startRegs;
+ memset(&startRegs, 0, sizeof(startRegs));
+#if defined(LUL_PLAT_x64_linux)
+ volatile uintptr_t block[3];
+ MOZ_ASSERT(sizeof(block) == 24);
+ __asm__ __volatile__(
+ "leaq 0(%%rip), %%r15" "\n\t"
+ "movq %%r15, 0(%0)" "\n\t"
+ "movq %%rsp, 8(%0)" "\n\t"
+ "movq %%rbp, 16(%0)" "\n"
+ : : "r"(&block[0]) : "memory", "r15"
+ );
+ startRegs.xip = TaggedUWord(block[0]);
+ startRegs.xsp = TaggedUWord(block[1]);
+ startRegs.xbp = TaggedUWord(block[2]);
+ const uintptr_t REDZONE_SIZE = 128;
+ uintptr_t start = block[1] - REDZONE_SIZE;
+#elif defined(LUL_PLAT_x86_linux) || defined(LUL_PLAT_x86_android)
+ volatile uintptr_t block[3];
+ MOZ_ASSERT(sizeof(block) == 12);
+ __asm__ __volatile__(
+ ".byte 0xE8,0x00,0x00,0x00,0x00"/*call next insn*/ "\n\t"
+ "popl %%edi" "\n\t"
+ "movl %%edi, 0(%0)" "\n\t"
+ "movl %%esp, 4(%0)" "\n\t"
+ "movl %%ebp, 8(%0)" "\n"
+ : : "r"(&block[0]) : "memory", "edi"
+ );
+ startRegs.xip = TaggedUWord(block[0]);
+ startRegs.xsp = TaggedUWord(block[1]);
+ startRegs.xbp = TaggedUWord(block[2]);
+ const uintptr_t REDZONE_SIZE = 0;
+ uintptr_t start = block[1] - REDZONE_SIZE;
+#elif defined(LUL_PLAT_arm_android)
+ volatile uintptr_t block[6];
+ MOZ_ASSERT(sizeof(block) == 24);
+ __asm__ __volatile__(
+ "mov r0, r15" "\n\t"
+ "str r0, [%0, #0]" "\n\t"
+ "str r14, [%0, #4]" "\n\t"
+ "str r13, [%0, #8]" "\n\t"
+ "str r12, [%0, #12]" "\n\t"
+ "str r11, [%0, #16]" "\n\t"
+ "str r7, [%0, #20]" "\n"
+ : : "r"(&block[0]) : "memory", "r0"
+ );
+ startRegs.r15 = TaggedUWord(block[0]);
+ startRegs.r14 = TaggedUWord(block[1]);
+ startRegs.r13 = TaggedUWord(block[2]);
+ startRegs.r12 = TaggedUWord(block[3]);
+ startRegs.r11 = TaggedUWord(block[4]);
+ startRegs.r7 = TaggedUWord(block[5]);
+ const uintptr_t REDZONE_SIZE = 0;
+ uintptr_t start = block[1] - REDZONE_SIZE;
+#else
+# error "Unsupported platform"
+#endif
+
+ // Get hold of the innermost LUL_UNIT_TEST_STACK_SIZE bytes of the
+ // stack.
+ uintptr_t end = start + LUL_UNIT_TEST_STACK_SIZE;
+ uintptr_t ws = sizeof(void*);
+ start &= ~(ws-1);
+ end &= ~(ws-1);
+ uintptr_t nToCopy = end - start;
+ if (nToCopy > lul::N_STACK_BYTES) {
+ nToCopy = lul::N_STACK_BYTES;
+ }
+ MOZ_ASSERT(nToCopy <= lul::N_STACK_BYTES);
+ StackImage* stackImg = new StackImage();
+ stackImg->mLen = nToCopy;
+ stackImg->mStartAvma = start;
+ if (nToCopy > 0) {
+ MOZ_MAKE_MEM_DEFINED((void*)start, nToCopy);
+ memcpy(&stackImg->mContents[0], (void*)start, nToCopy);
+ }
+
+ // Unwind it.
+ const int MAX_TEST_FRAMES = 64;
+ uintptr_t framePCs[MAX_TEST_FRAMES];
+ uintptr_t frameSPs[MAX_TEST_FRAMES];
+ size_t framesAvail = mozilla::ArrayLength(framePCs);
+ size_t framesUsed = 0;
+ size_t scannedFramesAllowed = 0;
+ size_t scannedFramesAcquired = 0;
+ aLUL->Unwind( &framePCs[0], &frameSPs[0],
+ &framesUsed, &scannedFramesAcquired,
+ framesAvail, scannedFramesAllowed,
+ &startRegs, stackImg );
+
+ delete stackImg;
+
+ //if (0) {
+ // // Show what we have.
+ // fprintf(stderr, "Got %d frames:\n", (int)framesUsed);
+ // for (size_t i = 0; i < framesUsed; i++) {
+ // fprintf(stderr, " [%2d] SP %p PC %p\n",
+ // (int)i, (void*)frameSPs[i], (void*)framePCs[i]);
+ // }
+ // fprintf(stderr, "\n");
+ //}
+
+ // Check to see if there's a consistent binding between digits in
+ // the director string ('1' .. '8') and the PC values acquired by
+ // the unwind. If there isn't, the unwinding has failed somehow.
+ uintptr_t binding[8]; // binding for '1' .. binding for '8'
+ memset((void*)binding, 0, sizeof(binding));
+
+ // The general plan is to work backwards along the director string
+ // and forwards along the framePCs array. Doing so corresponds to
+ // working outwards from the innermost frame of the recursive test set.
+ const char* cursor = dstring;
+
+ // Find the end. This leaves |cursor| two bytes past the first
+ // character we want to look at -- see comment below.
+ while (*cursor) cursor++;
+
+ // Counts the number of consistent frames.
+ size_t nConsistent = 0;
+
+ // Iterate back to the start of the director string. The starting
+ // points are a bit complex. We can't use framePCs[0] because that
+ // contains the PC in this frame (above). We can't use framePCs[1]
+ // because that will contain the PC at return point in the recursive
+ // test group (TestFn[1-8]) for their call "out" to this function,
+ // GetAndCheckStackTrace. Although LUL will compute a correct
+ // return address, that will not be the same return address as for a
+ // recursive call out of the the function to another function in the
+ // group. Hence we can only start consistency checking at
+ // framePCs[2].
+ //
+ // To be consistent, then, we must ignore the last element in the
+ // director string as that corresponds to framePCs[1]. Hence the
+ // start points are: framePCs[2] and the director string 2 bytes
+ // before the terminating zero.
+ //
+ // Also as a result of this, the number of consistent frames counted
+ // will always be one less than the length of the director string
+ // (not including its terminating zero).
+ size_t frameIx;
+ for (cursor = cursor-2, frameIx = 2;
+ cursor >= dstring && frameIx < framesUsed;
+ cursor--, frameIx++) {
+ char c = *cursor;
+ uintptr_t pc = framePCs[frameIx];
+ // If this doesn't hold, the director string is ill-formed.
+ MOZ_ASSERT(c >= '1' && c <= '8');
+ int n = ((int)c) - ((int)'1');
+ if (binding[n] == 0) {
+ // There's no binding for |c| yet, so install |pc| and carry on.
+ binding[n] = pc;
+ nConsistent++;
+ continue;
+ }
+ // There's a pre-existing binding for |c|. Check it's consistent.
+ if (binding[n] != pc) {
+ // Not consistent. Give up now.
+ break;
+ }
+ // Consistent. Keep going.
+ nConsistent++;
+ }
+
+ // So, did we succeed?
+ bool passed = nConsistent+1 == strlen(dstring);
+
+ // Show the results.
+ char buf[200];
+ SprintfLiteral(buf, "LULUnitTest: dstring = %s\n", dstring);
+ buf[sizeof(buf)-1] = 0;
+ aLUL->mLog(buf);
+ SprintfLiteral(buf,
+ "LULUnitTest: %d consistent, %d in dstring: %s\n",
+ (int)nConsistent, (int)strlen(dstring),
+ passed ? "PASS" : "FAIL");
+ buf[sizeof(buf)-1] = 0;
+ aLUL->mLog(buf);
+
+ return passed;
+}
+
+
+// Macro magic to create a set of 8 mutually recursive functions with
+// varying frame sizes. These will recurse amongst themselves as
+// specified by |strP|, the directory string, and call
+// GetAndCheckStackTrace when the string becomes empty, passing it the
+// original value of the string. This checks the result, printing
+// results on |aLUL|'s logging sink, and also returns a boolean
+// indicating whether or not the results are acceptable (correct).
+
+#define DECL_TEST_FN(NAME) \
+ bool NAME(LUL* aLUL, const char* strPorig, const char* strP);
+
+#define GEN_TEST_FN(NAME, FRAMESIZE) \
+ bool NAME(LUL* aLUL, const char* strPorig, const char* strP) { \
+ volatile char space[FRAMESIZE]; \
+ memset((char*)&space[0], 0, sizeof(space)); \
+ if (*strP == '\0') { \
+ /* We've come to the end of the director string. */ \
+ /* Take a stack snapshot. */ \
+ return GetAndCheckStackTrace(aLUL, strPorig); \
+ } else { \
+ /* Recurse onwards. This is a bit subtle. The obvious */ \
+ /* thing to do here is call onwards directly, from within the */ \
+ /* arms of the case statement. That gives a problem in that */ \
+ /* there will be multiple return points inside each function when */ \
+ /* unwinding, so it will be difficult to check for consistency */ \
+ /* against the director string. Instead, we make an indirect */ \
+ /* call, so as to guarantee that there is only one call site */ \
+ /* within each function. This does assume that the compiler */ \
+ /* won't transform it back to the simple direct-call form. */ \
+ /* To discourage it from doing so, the call is bracketed with */ \
+ /* __asm__ __volatile__ sections so as to make it not-movable. */ \
+ bool (*nextFn)(LUL*, const char*, const char*) = NULL; \
+ switch (*strP) { \
+ case '1': nextFn = TestFn1; break; \
+ case '2': nextFn = TestFn2; break; \
+ case '3': nextFn = TestFn3; break; \
+ case '4': nextFn = TestFn4; break; \
+ case '5': nextFn = TestFn5; break; \
+ case '6': nextFn = TestFn6; break; \
+ case '7': nextFn = TestFn7; break; \
+ case '8': nextFn = TestFn8; break; \
+ default: nextFn = TestFn8; break; \
+ } \
+ __asm__ __volatile__("":::"cc","memory"); \
+ bool passed = nextFn(aLUL, strPorig, strP+1); \
+ __asm__ __volatile__("":::"cc","memory"); \
+ return passed; \
+ } \
+ }
+
+// The test functions are mutually recursive, so it is necessary to
+// declare them before defining them.
+DECL_TEST_FN(TestFn1)
+DECL_TEST_FN(TestFn2)
+DECL_TEST_FN(TestFn3)
+DECL_TEST_FN(TestFn4)
+DECL_TEST_FN(TestFn5)
+DECL_TEST_FN(TestFn6)
+DECL_TEST_FN(TestFn7)
+DECL_TEST_FN(TestFn8)
+
+GEN_TEST_FN(TestFn1, 123)
+GEN_TEST_FN(TestFn2, 456)
+GEN_TEST_FN(TestFn3, 789)
+GEN_TEST_FN(TestFn4, 23)
+GEN_TEST_FN(TestFn5, 47)
+GEN_TEST_FN(TestFn6, 117)
+GEN_TEST_FN(TestFn7, 1)
+GEN_TEST_FN(TestFn8, 99)
+
+
+// This starts the test sequence going. Call here to generate a
+// sequence of calls as directed by the string |dstring|. The call
+// sequence will, from its innermost frame, finish by calling
+// GetAndCheckStackTrace() and passing it |dstring|.
+// GetAndCheckStackTrace() will unwind the stack, check consistency
+// of those results against |dstring|, and print a pass/fail message
+// to aLUL's logging sink. It also updates the counters in *aNTests
+// and aNTestsPassed.
+__attribute__((noinline)) void
+TestUnw(/*OUT*/int* aNTests, /*OUT*/int*aNTestsPassed,
+ LUL* aLUL, const char* dstring)
+{
+ // Ensure that the stack has at least this much space on it. This
+ // makes it safe to saw off the top LUL_UNIT_TEST_STACK_SIZE bytes
+ // and hand it to LUL. Safe in the sense that no segfault can
+ // happen because the stack is at least this big. This is all
+ // somewhat dubious in the sense that a sufficiently clever compiler
+ // (clang, for one) can figure out that space[] is unused and delete
+ // it from the frame. Hence the somewhat elaborate hoop jumping to
+ // fill it up before the call and to at least appear to use the
+ // value afterwards.
+ int i;
+ volatile char space[LUL_UNIT_TEST_STACK_SIZE];
+ for (i = 0; i < LUL_UNIT_TEST_STACK_SIZE; i++) {
+ space[i] = (char)(i & 0x7F);
+ }
+
+ // Really run the test.
+ bool passed = TestFn1(aLUL, dstring, dstring);
+
+ // Appear to use space[], by visiting the value to compute some kind
+ // of checksum, and then (apparently) using the checksum.
+ int sum = 0;
+ for (i = 0; i < LUL_UNIT_TEST_STACK_SIZE; i++) {
+ // If this doesn't fool LLVM, I don't know what will.
+ sum += space[i] - 3*i;
+ }
+ __asm__ __volatile__("" : : "r"(sum));
+
+ // Update the counters.
+ (*aNTests)++;
+ if (passed) {
+ (*aNTestsPassed)++;
+ }
+}
+
+
+void
+RunLulUnitTests(/*OUT*/int* aNTests, /*OUT*/int*aNTestsPassed, LUL* aLUL)
+{
+ aLUL->mLog(":\n");
+ aLUL->mLog("LULUnitTest: BEGIN\n");
+ *aNTests = *aNTestsPassed = 0;
+ TestUnw(aNTests, aNTestsPassed, aLUL, "11111111");
+ TestUnw(aNTests, aNTestsPassed, aLUL, "11222211");
+ TestUnw(aNTests, aNTestsPassed, aLUL, "111222333");
+ TestUnw(aNTests, aNTestsPassed, aLUL, "1212121231212331212121212121212");
+ TestUnw(aNTests, aNTestsPassed, aLUL, "31415827271828325332173258");
+ TestUnw(aNTests, aNTestsPassed, aLUL,
+ "123456781122334455667788777777777777777777777");
+ aLUL->mLog("LULUnitTest: END\n");
+ aLUL->mLog(":\n");
+}
+
+
+} // namespace lul