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DebugInfo: Factor out parsing compile unit DIEs to a separate function. Improve code style and comments.

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No functionality change.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@186315 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Alexey Samsonov 2013-07-15 08:43:35 +00:00
parent 3c70fcf02b
commit 40d8c69c59
2 changed files with 69 additions and 77 deletions
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112
lib/DebugInfo/DWARFCompileUnit.cpp
View File

@ -147,89 +147,95 @@ void DWARFCompileUnit::setDIERelations() {
curr_die->setParent(die_array_begin);
}
size_t DWARFCompileUnit::extractDIEsIfNeeded(bool cu_die_only) {
const size_t initial_die_array_size = DieArray.size();
if ((cu_die_only && initial_die_array_size > 0) ||
initial_die_array_size > 1)
return 0; // Already parsed
void DWARFCompileUnit::extractDIEsToVector(
bool AppendCUDie, bool AppendNonCUDies,
std::vector<DWARFDebugInfoEntryMinimal> &Dies) const {
if (!AppendCUDie && !AppendNonCUDies)
return;
// Set the offset to that of the first DIE and calculate the start of the
// next compilation unit header.
uint32_t offset = getFirstDIEOffset();
uint32_t next_cu_offset = getNextCompileUnitOffset();
DWARFDebugInfoEntryMinimal die;
// Keep a flat array of the DIE for binary lookup by DIE offset
uint32_t depth = 0;
// We are in our compile unit, parse starting at the offset
// we were told to parse
const uint8_t *fixed_form_sizes =
uint32_t Offset = getFirstDIEOffset();
uint32_t NextCUOffset = getNextCompileUnitOffset();
DWARFDebugInfoEntryMinimal DIE;
uint32_t Depth = 0;
const uint8_t *FixedFormSizes =
DWARFFormValue::getFixedFormSizes(getAddressByteSize(), getVersion());
bool IsCUDie = true;
while (offset < next_cu_offset &&
die.extractFast(this, fixed_form_sizes, &offset)) {
if (depth == 0) {
uint64_t base_addr =
die.getAttributeValueAsUnsigned(this, DW_AT_low_pc, -1U);
if (base_addr == -1U)
base_addr = die.getAttributeValueAsUnsigned(this, DW_AT_entry_pc, 0);
setBaseAddress(base_addr);
while (Offset < NextCUOffset &&
DIE.extractFast(this, FixedFormSizes, &Offset)) {
if (IsCUDie) {
if (AppendCUDie)
Dies.push_back(DIE);
if (!AppendNonCUDies)
break;
// The average bytes per DIE entry has been seen to be
// around 14-20 so let's pre-reserve the needed memory for
// our DIE entries accordingly.
Dies.reserve(Dies.size() + getDebugInfoSize() / 14);
IsCUDie = false;
} else {
Dies.push_back(DIE);
}
if (cu_die_only) {
addDIE(die);
return 1;
}
else if (depth == 0 && initial_die_array_size == 1)
// Don't append the CU die as we already did that
;
else
addDIE(die);
const DWARFAbbreviationDeclaration *abbrDecl =
die.getAbbreviationDeclarationPtr();
if (abbrDecl) {
const DWARFAbbreviationDeclaration *AbbrDecl =
DIE.getAbbreviationDeclarationPtr();
if (AbbrDecl) {
// Normal DIE
if (abbrDecl->hasChildren())
++depth;
if (AbbrDecl->hasChildren())
++Depth;
} else {
// NULL DIE.
if (depth > 0)
--depth;
if (depth == 0)
if (Depth > 0)
--Depth;
if (Depth == 0)
break; // We are done with this compile unit!
}
}
// Give a little bit of info if we encounter corrupt DWARF (our offset
// should always terminate at or before the start of the next compilation
// unit header).
if (offset > next_cu_offset)
if (Offset > NextCUOffset)
fprintf(stderr, "warning: DWARF compile unit extends beyond its "
"bounds cu 0x%8.8x at 0x%8.8x'\n", getOffset(), offset);
"bounds cu 0x%8.8x at 0x%8.8x'\n", getOffset(), Offset);
}
size_t DWARFCompileUnit::extractDIEsIfNeeded(bool CUDieOnly) {
if ((CUDieOnly && DieArray.size() > 0) ||
DieArray.size() > 1)
return 0; // Already parsed.
extractDIEsToVector(DieArray.empty(), !CUDieOnly, DieArray);
// Set the base address of current compile unit.
if (!DieArray.empty()) {
uint64_t BaseAddr =
DieArray[0].getAttributeValueAsUnsigned(this, DW_AT_low_pc, -1U);
if (BaseAddr == -1U)
BaseAddr = DieArray[0].getAttributeValueAsUnsigned(this, DW_AT_entry_pc, 0);
setBaseAddress(BaseAddr);
}
setDIERelations();
return DieArray.size();
}
void DWARFCompileUnit::clearDIEs(bool keep_compile_unit_die) {
if (DieArray.size() > (unsigned)keep_compile_unit_die) {
void DWARFCompileUnit::clearDIEs(bool KeepCUDie) {
if (DieArray.size() > (unsigned)KeepCUDie) {
// std::vectors never get any smaller when resized to a smaller size,
// or when clear() or erase() are called, the size will report that it
// is smaller, but the memory allocated remains intact (call capacity()
// to see this). So we need to create a temporary vector and swap the
// contents which will cause just the internal pointers to be swapped
// so that when "tmp_array" goes out of scope, it will destroy the
// so that when temporary vector goes out of scope, it will destroy the
// contents.
std::vector<DWARFDebugInfoEntryMinimal> TmpArray;
DieArray.swap(TmpArray);
// Save at least the compile unit DIE
std::vector<DWARFDebugInfoEntryMinimal> tmpArray;
DieArray.swap(tmpArray);
if (keep_compile_unit_die)
DieArray.push_back(tmpArray.front());
if (KeepCUDie)
DieArray.push_back(TmpArray.front());
}
}

34
lib/DebugInfo/DWARFCompileUnit.h
View File

@ -39,7 +39,7 @@ class DWARFCompileUnit {
const DWARFAbbreviationDeclarationSet *Abbrevs;
uint8_t AddrSize;
uint64_t BaseAddr;
// The compile unit debug information entry item.
// The compile unit debug information entry items.
std::vector<DWARFDebugInfoEntryMinimal> DieArray;
public:
@ -64,7 +64,7 @@ public:
/// extractDIEsIfNeeded - Parses a compile unit and indexes its DIEs if it
/// hasn't already been done. Returns the number of DIEs parsed at this call.
size_t extractDIEsIfNeeded(bool cu_die_only);
size_t extractDIEsIfNeeded(bool CUDieOnly);
/// extractRangeList - extracts the range list referenced by this compile
/// unit from .debug_ranges section. Returns true on success.
/// Requires that compile unit is already extracted.
@ -98,9 +98,7 @@ public:
const DWARFDebugInfoEntryMinimal *
getCompileUnitDIE(bool extract_cu_die_only = true) {
extractDIEsIfNeeded(extract_cu_die_only);
if (DieArray.empty())
return NULL;
return &DieArray[0];
return DieArray.empty() ? NULL : &DieArray[0];
}
const char *getCompilationDir();
@ -110,25 +108,6 @@ public:
/// parent, sibling and child pointers for quick DIE navigation.
void setDIERelations();
void addDIE(DWARFDebugInfoEntryMinimal &die) {
// The average bytes per DIE entry has been seen to be
// around 14-20 so lets pre-reserve the needed memory for
// our DIE entries accordingly. Search forward for "Compute
// average bytes per DIE" to see #if'ed out code that does
// that determination.
// Only reserve the memory if we are adding children of
// the main compile unit DIE. The compile unit DIE is always
// the first entry, so if our size is 1, then we are adding
// the first compile unit child DIE and should reserve
// the memory.
if (DieArray.empty())
DieArray.reserve(getDebugInfoSize() / 14);
DieArray.push_back(die);
}
void clearDIEs(bool keep_compile_unit_die);
void buildAddressRangeTable(DWARFDebugAranges *debug_aranges,
bool clear_dies_if_already_not_parsed);
@ -136,6 +115,13 @@ public:
/// Returns empty chain if there is no subprogram containing address.
DWARFDebugInfoEntryMinimal::InlinedChain getInlinedChainForAddress(
uint64_t Address);
private:
/// extractDIEsToVector - Appends all parsed DIEs to a vector.
void extractDIEsToVector(bool AppendCUDie, bool AppendNonCUDIEs,
std::vector<DWARFDebugInfoEntryMinimal> &DIEs) const;
/// clearDIEs - Clear parsed DIEs to keep memory usage low.
void clearDIEs(bool KeepCUDie);
};
}