MC: Simplify main section layout process by moving alignment into LayoutSection.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@99529 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/MC/MCAssembler.cpp b/lib/MC/MCAssembler.cpp
index c0ec04d..c3e2ca8 100644
--- a/lib/MC/MCAssembler.cpp
+++ b/lib/MC/MCAssembler.cpp
@@ -364,9 +364,29 @@
return IsResolved;
}
-void MCAssembler::LayoutSection(MCSectionData &SD,
- MCAsmLayout &Layout,
- uint64_t StartAddress) {
+uint64_t MCAssembler::LayoutSection(MCSectionData &SD,
+ MCAsmLayout &Layout,
+ uint64_t StartAddress) {
+ bool IsVirtual = getBackend().isVirtualSection(SD.getSection());
+
+ // Align this section if necessary by adding padding bytes to the previous
+ // section. It is safe to adjust this out-of-band, because no symbol or
+ // fragment is allowed to point past the end of the section at any time.
+ if (uint64_t Pad = OffsetToAlignment(StartAddress, SD.getAlignment())) {
+ // Unless this section is virtual (where we are allowed to adjust the offset
+ // freely), the padding goes in the previous section.
+ if (!IsVirtual) {
+ // Find the previous non-virtual section.
+ iterator it = &SD;
+ assert(it != begin() && "Invalid initial section address!");
+ for (--it; getBackend().isVirtualSection(it->getSection()); --it) ;
+ Layout.setSectionFileSize(&*it, Layout.getSectionFileSize(&*it) + Pad);
+ }
+
+ StartAddress += Pad;
+ }
+
+ // Set the aligned section address.
Layout.setSectionAddress(&SD, StartAddress);
uint64_t Address = StartAddress;
@@ -440,10 +460,12 @@
// Set the section sizes.
Layout.setSectionSize(&SD, Address - StartAddress);
- if (getBackend().isVirtualSection(SD.getSection()))
+ if (IsVirtual)
Layout.setSectionFileSize(&SD, 0);
else
Layout.setSectionFileSize(&SD, Address - StartAddress);
+
+ return Address;
}
/// WriteFragmentData - Write the \arg F data to the output file.
@@ -675,43 +697,22 @@
// Layout the concrete sections and fragments.
uint64_t Address = 0;
- MCSectionData *Prev = 0;
for (iterator it = begin(), ie = end(); it != ie; ++it) {
- MCSectionData &SD = *it;
-
// Skip virtual sections.
- if (getBackend().isVirtualSection(SD.getSection()))
+ if (getBackend().isVirtualSection(it->getSection()))
continue;
- // Align this section if necessary by adding padding bytes to the previous
- // section.
- if (uint64_t Pad = OffsetToAlignment(Address, it->getAlignment())) {
- assert(Prev && "Missing prev section!");
- Layout.setSectionFileSize(Prev, Layout.getSectionFileSize(Prev) + Pad);
- Address += Pad;
- }
-
// Layout the section fragments and its size.
- LayoutSection(SD, Layout, Address);
- Address += Layout.getSectionFileSize(&SD);
-
- Prev = &SD;
+ Address = LayoutSection(*it, Layout, Address);
}
// Layout the virtual sections.
for (iterator it = begin(), ie = end(); it != ie; ++it) {
- MCSectionData &SD = *it;
-
- if (!getBackend().isVirtualSection(SD.getSection()))
+ if (!getBackend().isVirtualSection(it->getSection()))
continue;
- // Align this section if necessary by adding padding bytes to the previous
- // section.
- if (uint64_t Pad = OffsetToAlignment(Address, it->getAlignment()))
- Address += Pad;
-
- LayoutSection(SD, Layout, Address);
- Address += Layout.getSectionSize(&SD);
+ // Layout the section fragments and its size.
+ Address = LayoutSection(*it, Layout, Address);
}
// Scan for fragments that need relaxation.