Adding upstream version 124.0.1.upstream/124.0.1

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 553 insertions, 0 deletions

diff --git a/mozglue/baseprofiler/lul/LulDwarfSummariser.cpp b/mozglue/baseprofiler/lul/LulDwarfSummariser.cpp
new file mode 100644
index 0000000000..ff0f212f6c
--- /dev/null
+++ b/mozglue/baseprofiler/lul/LulDwarfSummariser.cpp
@@ -0,0 +1,553 @@
+/* -*- 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 "LulDwarfSummariser.h"
+
+#include "mozilla/Assertions.h"
+#include "mozilla/Sprintf.h"
+
+#include "LulDwarfExt.h"
+
+// Set this to 1 for verbose logging
+#define DEBUG_SUMMARISER 0
+
+namespace lul {
+
+// Do |s64|'s lowest 32 bits sign extend back to |s64| itself?
+static inline bool fitsIn32Bits(int64 s64) {
+  return s64 == ((s64 & 0xffffffff) ^ 0x80000000) - 0x80000000;
+}
+
+// Check a LExpr prefix expression, starting at pfxInstrs[start] up to
+// the next PX_End instruction, to ensure that:
+// * It only mentions registers that are tracked on this target
+// * The start point is sane
+// If the expression is ok, return NULL.  Else return a pointer
+// a const char* holding a bit of text describing the problem.
+static const char* checkPfxExpr(const vector<PfxInstr>* pfxInstrs,
+                                int64_t start) {
+  size_t nInstrs = pfxInstrs->size();
+  if (start < 0 || start >= (ssize_t)nInstrs) {
+    return "bogus start point";
+  }
+  size_t i;
+  for (i = start; i < nInstrs; i++) {
+    PfxInstr pxi = (*pfxInstrs)[i];
+    if (pxi.mOpcode == PX_End) break;
+    if (pxi.mOpcode == PX_DwReg &&
+        !registerIsTracked((DW_REG_NUMBER)pxi.mOperand)) {
+      return "uses untracked reg";
+    }
+  }
+  return nullptr;  // success
+}
+
+Summariser::Summariser(SecMap* aSecMap, uintptr_t aTextBias,
+                       void (*aLog)(const char*))
+    : mSecMap(aSecMap), mTextBias(aTextBias), mLog(aLog) {
+  mCurrAddr = 0;
+  mMax1Addr = 0;  // Gives an empty range.
+
+  // Initialise the running RuleSet to "haven't got a clue" status.
+  new (&mCurrRules) RuleSet();
+}
+
+void Summariser::Entry(uintptr_t aAddress, uintptr_t aLength) {
+  aAddress += mTextBias;
+  if (DEBUG_SUMMARISER) {
+    char buf[100];
+    SprintfLiteral(buf, "LUL Entry(%llx, %llu)\n",
+                   (unsigned long long int)aAddress,
+                   (unsigned long long int)aLength);
+    mLog(buf);
+  }
+  // This throws away any previous summary, that is, assumes
+  // that the previous summary, if any, has been properly finished
+  // by a call to End().
+  mCurrAddr = aAddress;
+  mMax1Addr = aAddress + aLength;
+  new (&mCurrRules) RuleSet();
+}
+
+void Summariser::Rule(uintptr_t aAddress, int aNewReg, LExprHow how,
+                      int16_t oldReg, int64_t offset) {
+  aAddress += mTextBias;
+  if (DEBUG_SUMMARISER) {
+    char buf[100];
+    if (how == NODEREF || how == DEREF) {
+      bool deref = how == DEREF;
+      SprintfLiteral(buf, "LUL  0x%llx  old-r%d = %sr%d + %lld%s\n",
+                     (unsigned long long int)aAddress, aNewReg,
+                     deref ? "*(" : "", (int)oldReg, (long long int)offset,
+                     deref ? ")" : "");
+    } else if (how == PFXEXPR) {
+      SprintfLiteral(buf, "LUL  0x%llx  old-r%d = pfx-expr-at %lld\n",
+                     (unsigned long long int)aAddress, aNewReg,
+                     (long long int)offset);
+    } else {
+      SprintfLiteral(buf, "LUL  0x%llx  old-r%d = (invalid LExpr!)\n",
+                     (unsigned long long int)aAddress, aNewReg);
+    }
+    mLog(buf);
+  }
+
+  if (mCurrAddr < aAddress) {
+    // Flush the existing summary first.
+    mCurrRules.mAddr = mCurrAddr;
+    mCurrRules.mLen = aAddress - mCurrAddr;
+    mSecMap->AddRuleSet(&mCurrRules);
+    if (DEBUG_SUMMARISER) {
+      mLog("LUL  ");
+      mCurrRules.Print(mLog);
+      mLog("\n");
+    }
+    mCurrAddr = aAddress;
+  }
+
+  // If for some reason summarisation fails, either or both of these
+  // become non-null and point at constant text describing the
+  // problem.  Using two rather than just one avoids complications of
+  // having to concatenate two strings to produce a complete error message.
+  const char* reason1 = nullptr;
+  const char* reason2 = nullptr;
+
+  // |offset| needs to be a 32 bit value that sign extends to 64 bits
+  // on a 64 bit target.  We will need to incorporate |offset| into
+  // any LExpr made here.  So we may as well check it right now.
+  if (!fitsIn32Bits(offset)) {
+    reason1 = "offset not in signed 32-bit range";
+    goto cant_summarise;
+  }
+
+  // FIXME: factor out common parts of the arch-dependent summarisers.
+
+#if defined(GP_ARCH_arm)
+
+  // ----------------- arm ----------------- //
+
+  // Now, can we add the rule to our summary?  This depends on whether
+  // the registers and the overall expression are representable.  This
+  // is the heart of the summarisation process.
+  switch (aNewReg) {
+    case DW_REG_CFA:
+      // This is a rule that defines the CFA.  The only forms we
+      // choose to represent are: r7/11/12/13 + offset.  The offset
+      // must fit into 32 bits since 'uintptr_t' is 32 bit on ARM,
+      // hence there is no need to check it for overflow.
+      if (how != NODEREF) {
+        reason1 = "rule for DW_REG_CFA: invalid |how|";
+        goto cant_summarise;
+      }
+      switch (oldReg) {
+        case DW_REG_ARM_R7:
+        case DW_REG_ARM_R11:
+        case DW_REG_ARM_R12:
+        case DW_REG_ARM_R13:
+          break;
+        default:
+          reason1 = "rule for DW_REG_CFA: invalid |oldReg|";
+          goto cant_summarise;
+      }
+      mCurrRules.mCfaExpr = LExpr(how, oldReg, offset);
+      break;
+
+    case DW_REG_ARM_R7:
+    case DW_REG_ARM_R11:
+    case DW_REG_ARM_R12:
+    case DW_REG_ARM_R13:
+    case DW_REG_ARM_R14:
+    case DW_REG_ARM_R15: {
+      // This is a new rule for R7, R11, R12, R13 (SP), R14 (LR) or
+      // R15 (the return address).
+      switch (how) {
+        case NODEREF:
+        case DEREF:
+          // Check the old register is one we're tracking.
+          if (!registerIsTracked((DW_REG_NUMBER)oldReg) &&
+              oldReg != DW_REG_CFA) {
+            reason1 = "rule for R7/11/12/13/14/15: uses untracked reg";
+            goto cant_summarise;
+          }
+          break;
+        case PFXEXPR: {
+          // Check that the prefix expression only mentions tracked registers.
+          const vector<PfxInstr>* pfxInstrs = mSecMap->GetPfxInstrs();
+          reason2 = checkPfxExpr(pfxInstrs, offset);
+          if (reason2) {
+            reason1 = "rule for R7/11/12/13/14/15: ";
+            goto cant_summarise;
+          }
+          break;
+        }
+        default:
+          goto cant_summarise;
+      }
+      LExpr expr = LExpr(how, oldReg, offset);
+      switch (aNewReg) {
+        case DW_REG_ARM_R7:
+          mCurrRules.mR7expr = expr;
+          break;
+        case DW_REG_ARM_R11:
+          mCurrRules.mR11expr = expr;
+          break;
+        case DW_REG_ARM_R12:
+          mCurrRules.mR12expr = expr;
+          break;
+        case DW_REG_ARM_R13:
+          mCurrRules.mR13expr = expr;
+          break;
+        case DW_REG_ARM_R14:
+          mCurrRules.mR14expr = expr;
+          break;
+        case DW_REG_ARM_R15:
+          mCurrRules.mR15expr = expr;
+          break;
+        default:
+          MOZ_ASSERT(0);
+      }
+      break;
+    }
+
+    default:
+      // Leave |reason1| and |reason2| unset here.  This program point
+      // is reached so often that it causes a flood of "Can't
+      // summarise" messages.  In any case, we don't really care about
+      // the fact that this summary would produce a new value for a
+      // register that we're not tracking.  We do on the other hand
+      // care if the summary's expression *uses* a register that we're
+      // not tracking.  But in that case one of the above failures
+      // should tell us which.
+      goto cant_summarise;
+  }
+
+  // Mark callee-saved registers (r4 .. r11) as unchanged, if there is
+  // no other information about them.  FIXME: do this just once, at
+  // the point where the ruleset is committed.
+  if (mCurrRules.mR7expr.mHow == UNKNOWN) {
+    mCurrRules.mR7expr = LExpr(NODEREF, DW_REG_ARM_R7, 0);
+  }
+  if (mCurrRules.mR11expr.mHow == UNKNOWN) {
+    mCurrRules.mR11expr = LExpr(NODEREF, DW_REG_ARM_R11, 0);
+  }
+  if (mCurrRules.mR12expr.mHow == UNKNOWN) {
+    mCurrRules.mR12expr = LExpr(NODEREF, DW_REG_ARM_R12, 0);
+  }
+
+  // The old r13 (SP) value before the call is always the same as the
+  // CFA.
+  mCurrRules.mR13expr = LExpr(NODEREF, DW_REG_CFA, 0);
+
+  // If there's no information about R15 (the return address), say
+  // it's a copy of R14 (the link register).
+  if (mCurrRules.mR15expr.mHow == UNKNOWN) {
+    mCurrRules.mR15expr = LExpr(NODEREF, DW_REG_ARM_R14, 0);
+  }
+
+#elif defined(GP_ARCH_arm64)
+
+  // ----------------- arm64 ----------------- //
+
+  switch (aNewReg) {
+    case DW_REG_CFA:
+      if (how != NODEREF) {
+        reason1 = "rule for DW_REG_CFA: invalid |how|";
+        goto cant_summarise;
+      }
+      switch (oldReg) {
+        case DW_REG_AARCH64_X29:
+        case DW_REG_AARCH64_SP:
+          break;
+        default:
+          reason1 = "rule for DW_REG_CFA: invalid |oldReg|";
+          goto cant_summarise;
+      }
+      mCurrRules.mCfaExpr = LExpr(how, oldReg, offset);
+      break;
+
+    case DW_REG_AARCH64_X29:
+    case DW_REG_AARCH64_X30:
+    case DW_REG_AARCH64_SP: {
+      switch (how) {
+        case NODEREF:
+        case DEREF:
+          // Check the old register is one we're tracking.
+          if (!registerIsTracked((DW_REG_NUMBER)oldReg) &&
+              oldReg != DW_REG_CFA) {
+            reason1 = "rule for X29/X30/SP: uses untracked reg";
+            goto cant_summarise;
+          }
+          break;
+        case PFXEXPR: {
+          // Check that the prefix expression only mentions tracked registers.
+          const vector<PfxInstr>* pfxInstrs = mSecMap->GetPfxInstrs();
+          reason2 = checkPfxExpr(pfxInstrs, offset);
+          if (reason2) {
+            reason1 = "rule for X29/X30/SP: ";
+            goto cant_summarise;
+          }
+          break;
+        }
+        default:
+          goto cant_summarise;
+      }
+      LExpr expr = LExpr(how, oldReg, offset);
+      switch (aNewReg) {
+        case DW_REG_AARCH64_X29:
+          mCurrRules.mX29expr = expr;
+          break;
+        case DW_REG_AARCH64_X30:
+          mCurrRules.mX30expr = expr;
+          break;
+        case DW_REG_AARCH64_SP:
+          mCurrRules.mSPexpr = expr;
+          break;
+        default:
+          MOZ_ASSERT(0);
+      }
+      break;
+    }
+    default:
+      // Leave |reason1| and |reason2| unset here, for the reasons explained
+      // in the analogous point
+      goto cant_summarise;
+  }
+
+  if (mCurrRules.mX29expr.mHow == UNKNOWN) {
+    mCurrRules.mX29expr = LExpr(NODEREF, DW_REG_AARCH64_X29, 0);
+  }
+  if (mCurrRules.mX30expr.mHow == UNKNOWN) {
+    mCurrRules.mX30expr = LExpr(NODEREF, DW_REG_AARCH64_X30, 0);
+  }
+  // On aarch64, it seems the old SP value before the call is always the
+  // same as the CFA.  Therefore, in the absence of any other way to
+  // recover the SP, specify that the CFA should be copied.
+  if (mCurrRules.mSPexpr.mHow == UNKNOWN) {
+    mCurrRules.mSPexpr = LExpr(NODEREF, DW_REG_CFA, 0);
+  }
+#elif defined(GP_ARCH_amd64) || defined(GP_ARCH_x86)
+
+  // ---------------- x64/x86 ---------------- //
+
+  // Now, can we add the rule to our summary?  This depends on whether
+  // the registers and the overall expression are representable.  This
+  // is the heart of the summarisation process.
+  switch (aNewReg) {
+    case DW_REG_CFA: {
+      // This is a rule that defines the CFA.  The only forms we choose to
+      // represent are: = SP+offset, = FP+offset, or =prefix-expr.
+      switch (how) {
+        case NODEREF:
+          if (oldReg != DW_REG_INTEL_XSP && oldReg != DW_REG_INTEL_XBP) {
+            reason1 = "rule for DW_REG_CFA: invalid |oldReg|";
+            goto cant_summarise;
+          }
+          break;
+        case DEREF:
+          reason1 = "rule for DW_REG_CFA: invalid |how|";
+          goto cant_summarise;
+        case PFXEXPR: {
+          // Check that the prefix expression only mentions tracked registers.
+          const vector<PfxInstr>* pfxInstrs = mSecMap->GetPfxInstrs();
+          reason2 = checkPfxExpr(pfxInstrs, offset);
+          if (reason2) {
+            reason1 = "rule for CFA: ";
+            goto cant_summarise;
+          }
+          break;
+        }
+        default:
+          goto cant_summarise;
+      }
+      mCurrRules.mCfaExpr = LExpr(how, oldReg, offset);
+      break;
+    }
+
+    case DW_REG_INTEL_XSP:
+    case DW_REG_INTEL_XBP:
+    case DW_REG_INTEL_XIP: {
+      // This is a new rule for XSP, XBP or XIP (the return address).
+      switch (how) {
+        case NODEREF:
+        case DEREF:
+          // Check the old register is one we're tracking.
+          if (!registerIsTracked((DW_REG_NUMBER)oldReg) &&
+              oldReg != DW_REG_CFA) {
+            reason1 = "rule for XSP/XBP/XIP: uses untracked reg";
+            goto cant_summarise;
+          }
+          break;
+        case PFXEXPR: {
+          // Check that the prefix expression only mentions tracked registers.
+          const vector<PfxInstr>* pfxInstrs = mSecMap->GetPfxInstrs();
+          reason2 = checkPfxExpr(pfxInstrs, offset);
+          if (reason2) {
+            reason1 = "rule for XSP/XBP/XIP: ";
+            goto cant_summarise;
+          }
+          break;
+        }
+        default:
+          goto cant_summarise;
+      }
+      LExpr expr = LExpr(how, oldReg, offset);
+      switch (aNewReg) {
+        case DW_REG_INTEL_XBP:
+          mCurrRules.mXbpExpr = expr;
+          break;
+        case DW_REG_INTEL_XSP:
+          mCurrRules.mXspExpr = expr;
+          break;
+        case DW_REG_INTEL_XIP:
+          mCurrRules.mXipExpr = expr;
+          break;
+        default:
+          MOZ_CRASH("impossible value for aNewReg");
+      }
+      break;
+    }
+
+    default:
+      // Leave |reason1| and |reason2| unset here, for the reasons
+      // explained in the analogous point in the ARM case just above.
+      goto cant_summarise;
+  }
+
+  // On Intel, it seems the old SP value before the call is always the
+  // same as the CFA.  Therefore, in the absence of any other way to
+  // recover the SP, specify that the CFA should be copied.
+  if (mCurrRules.mXspExpr.mHow == UNKNOWN) {
+    mCurrRules.mXspExpr = LExpr(NODEREF, DW_REG_CFA, 0);
+  }
+
+  // Also, gcc says "Undef" for BP when it is unchanged.
+  if (mCurrRules.mXbpExpr.mHow == UNKNOWN) {
+    mCurrRules.mXbpExpr = LExpr(NODEREF, DW_REG_INTEL_XBP, 0);
+  }
+
+#elif defined(GP_ARCH_mips64)
+  // ---------------- mips ---------------- //
+  //
+  // Now, can we add the rule to our summary?  This depends on whether
+  // the registers and the overall expression are representable.  This
+  // is the heart of the summarisation process.
+  switch (aNewReg) {
+    case DW_REG_CFA:
+      // This is a rule that defines the CFA.  The only forms we can
+      // represent are: = SP+offset or = FP+offset.
+      if (how != NODEREF) {
+        reason1 = "rule for DW_REG_CFA: invalid |how|";
+        goto cant_summarise;
+      }
+      if (oldReg != DW_REG_MIPS_SP && oldReg != DW_REG_MIPS_FP) {
+        reason1 = "rule for DW_REG_CFA: invalid |oldReg|";
+        goto cant_summarise;
+      }
+      mCurrRules.mCfaExpr = LExpr(how, oldReg, offset);
+      break;
+
+    case DW_REG_MIPS_SP:
+    case DW_REG_MIPS_FP:
+    case DW_REG_MIPS_PC: {
+      // This is a new rule for SP, FP or PC (the return address).
+      switch (how) {
+        case NODEREF:
+        case DEREF:
+          // Check the old register is one we're tracking.
+          if (!registerIsTracked((DW_REG_NUMBER)oldReg) &&
+              oldReg != DW_REG_CFA) {
+            reason1 = "rule for SP/FP/PC: uses untracked reg";
+            goto cant_summarise;
+          }
+          break;
+        case PFXEXPR: {
+          // Check that the prefix expression only mentions tracked registers.
+          const vector<PfxInstr>* pfxInstrs = mSecMap->GetPfxInstrs();
+          reason2 = checkPfxExpr(pfxInstrs, offset);
+          if (reason2) {
+            reason1 = "rule for SP/FP/PC: ";
+            goto cant_summarise;
+          }
+          break;
+        }
+        default:
+          goto cant_summarise;
+      }
+      LExpr expr = LExpr(how, oldReg, offset);
+      switch (aNewReg) {
+        case DW_REG_MIPS_FP:
+          mCurrRules.mFPexpr = expr;
+          break;
+        case DW_REG_MIPS_SP:
+          mCurrRules.mSPexpr = expr;
+          break;
+        case DW_REG_MIPS_PC:
+          mCurrRules.mPCexpr = expr;
+          break;
+        default:
+          MOZ_CRASH("impossible value for aNewReg");
+      }
+      break;
+    }
+    default:
+      // Leave |reason1| and |reason2| unset here, for the reasons
+      // explained in the analogous point in the ARM case just above.
+      goto cant_summarise;
+  }
+
+  // On MIPS, it seems the old SP value before the call is always the
+  // same as the CFA.  Therefore, in the absence of any other way to
+  // recover the SP, specify that the CFA should be copied.
+  if (mCurrRules.mSPexpr.mHow == UNKNOWN) {
+    mCurrRules.mSPexpr = LExpr(NODEREF, DW_REG_CFA, 0);
+  }
+
+  // Also, gcc says "Undef" for FP when it is unchanged.
+  if (mCurrRules.mFPexpr.mHow == UNKNOWN) {
+    mCurrRules.mFPexpr = LExpr(NODEREF, DW_REG_MIPS_FP, 0);
+  }
+
+#else
+
+#  error "Unsupported arch"
+#endif
+
+  return;
+
+cant_summarise:
+  if (reason1 || reason2) {
+    char buf[200];
+    SprintfLiteral(buf,
+                   "LUL  can't summarise: "
+                   "SVMA=0x%llx: %s%s, expr=LExpr(%s,%u,%lld)\n",
+                   (unsigned long long int)(aAddress - mTextBias),
+                   reason1 ? reason1 : "", reason2 ? reason2 : "",
+                   NameOf_LExprHow(how), (unsigned int)oldReg,
+                   (long long int)offset);
+    mLog(buf);
+  }
+}
+
+uint32_t Summariser::AddPfxInstr(PfxInstr pfxi) {
+  return mSecMap->AddPfxInstr(pfxi);
+}
+
+void Summariser::End() {
+  if (DEBUG_SUMMARISER) {
+    mLog("LUL End\n");
+  }
+  if (mCurrAddr < mMax1Addr) {
+    mCurrRules.mAddr = mCurrAddr;
+    mCurrRules.mLen = mMax1Addr - mCurrAddr;
+    mSecMap->AddRuleSet(&mCurrRules);
+    if (DEBUG_SUMMARISER) {
+      mLog("LUL  ");
+      mCurrRules.Print(mLog);
+      mLog("\n");
+    }
+  }
+}
+
+}  // namespace lul