Handle /align option.

Differential Revision: https://reviews.llvm.org/D65736

llvm-svn: 368145

lld/COFF/Config.h

@@ -189,6 +189,7 @@ struct Configuration {
   // Used for /thinlto-object-suffix-replace:
   std::pair<llvm::StringRef, llvm::StringRef> thinLTOObjectSuffixReplace;
 
+  uint64_t align = 4096;
   uint64_t imageBase = -1;
   uint64_t fileAlign = 512;
   uint64_t stackReserve = 1024 * 1024;

lld/COFF/Driver.cpp

@@ -36,6 +36,7 @@
 #include "llvm/Option/Option.h"
 #include "llvm/Support/Debug.h"
 #include "llvm/Support/LEB128.h"
+#include "llvm/Support/MathExtras.h"
 #include "llvm/Support/Path.h"
 #include "llvm/Support/Process.h"
 #include "llvm/Support/TarWriter.h"
@@ -1422,6 +1423,13 @@ void LinkerDriver::link(ArrayRef<const char *> argsArr) {
   for (auto *arg : args.filtered(OPT_section))
     parseSection(arg->getValue());
 
+  // Handle /align
+  if (auto *arg = args.getLastArg(OPT_align)) {
+    parseNumbers(arg->getValue(), &config->align);
+    if (!isPowerOf2_64(config->align))
+      error("/align: not a power of two: " + StringRef(arg->getValue()));
+  }
+
   // Handle /aligncomm
   for (auto *arg : args.filtered(OPT_aligncomm))
     parseAligncomm(arg->getValue());

lld/COFF/Writer.cpp

@@ -1205,9 +1205,11 @@ void Writer::assignAddresses() {
   sizeOfHeaders +=
       config->is64() ? sizeof(pe32plus_header) : sizeof(pe32_header);
   sizeOfHeaders = alignTo(sizeOfHeaders, config->fileAlign);
-  uint64_t rva = pageSize; // The first page is kept unmapped.
   fileSize = sizeOfHeaders;
 
+  // The first page is kept unmapped.
+  uint64_t rva = alignTo(sizeOfHeaders, config->align);
+
   for (OutputSection *sec : outputSections) {
     if (sec == relocSec)
       addBaserels();
@@ -1237,10 +1239,10 @@ void Writer::assignAddresses() {
     sec->header.SizeOfRawData = rawSize;
     if (rawSize != 0)
       sec->header.PointerToRawData = fileSize;
-    rva += alignTo(virtualSize, pageSize);
+    rva += alignTo(virtualSize, config->align);
     fileSize += alignTo(rawSize, config->fileAlign);
   }
-  sizeOfImage = alignTo(rva, pageSize);
+  sizeOfImage = alignTo(rva, config->align);
 
   // Assign addresses to sections in MergeChunks.
   for (MergeChunk *mc : MergeChunk::instances)
@@ -1309,7 +1311,7 @@ template <typename PEHeaderTy> void Writer::writeHeader() {
   pe->MinorLinkerVersion = 0;
 
   pe->ImageBase = config->imageBase;
-  pe->SectionAlignment = pageSize;
+  pe->SectionAlignment = config->align;
   pe->FileAlignment = config->fileAlign;
   pe->MajorImageVersion = config->majorImageVersion;
   pe->MinorImageVersion = config->minorImageVersion;

lld/test/COFF/align.s

@@ -0,0 +1,45 @@
+# RUN: yaml2obj < %s > %t.obj
+# RUN: lld-link /out:%t.exe /entry:main /align:32 %t.obj
+# RUN: llvm-readobj --file-headers %t.exe | FileCheck %s
+
+# CHECK: SectionAlignment: 32
+
+--- !COFF
+header:
+  Machine:         IMAGE_FILE_MACHINE_AMD64
+  Characteristics: []
+sections:
+  - Name:            .text
+    Characteristics: [ IMAGE_SCN_CNT_CODE, IMAGE_SCN_MEM_EXECUTE, IMAGE_SCN_MEM_READ ]
+    Alignment:       4096
+    SectionData:     0000000000000000
+    Relocations:
+      - VirtualAddress:  0
+        SymbolName:      __ImageBase
+        Type:            IMAGE_REL_AMD64_ADDR64
+symbols:
+  - Name:            .text
+    Value:           0
+    SectionNumber:   1
+    SimpleType:      IMAGE_SYM_TYPE_NULL
+    ComplexType:     IMAGE_SYM_DTYPE_NULL
+    StorageClass:    IMAGE_SYM_CLASS_STATIC
+    SectionDefinition:
+      Length:          8
+      NumberOfRelocations: 1
+      NumberOfLinenumbers: 0
+      CheckSum:        0
+      Number:          0
+  - Name:            main
+    Value:           0
+    SectionNumber:   1
+    SimpleType:      IMAGE_SYM_TYPE_NULL
+    ComplexType:     IMAGE_SYM_DTYPE_NULL
+    StorageClass:    IMAGE_SYM_CLASS_EXTERNAL
+  - Name:            __ImageBase
+    Value:           0
+    SectionNumber:   0
+    SimpleType:      IMAGE_SYM_TYPE_NULL
+    ComplexType:     IMAGE_SYM_DTYPE_NULL
+    StorageClass:    IMAGE_SYM_CLASS_EXTERNAL
+...