[Documentation] Always use SVG for dot-generated doxygen images. (#136843)

Despite our attempt (build-docs.sh)
to build the documentation with SVG,
it still uses PNG https://llvm.org/doxygen/classllvm_1_1StringRef.html,

and that renders terribly on any high dpi display.

SVG leads to smasller installation and works fine
on all browser (that has been true for _a while_
https://caniuse.com/svg), so this patch just unconditionally build all
dot graphs as SVG in all subprojects and remove the option.

Author: cor3ntin

bolt/docs/CMakeLists.txt

@@ -48,14 +48,6 @@ if (LLVM_ENABLE_DOXYGEN)
     set(bolt_doxygen_qhp_cust_filter_attrs "")
   endif()
 
-  option(LLVM_DOXYGEN_SVG
-    "Use svg instead of png files for doxygen graphs." OFF)
-  if (LLVM_DOXYGEN_SVG)
-    set(DOT_IMAGE_FORMAT "svg")
-  else()
-    set(DOT_IMAGE_FORMAT "png")
-  endif()
-
   configure_file(${CMAKE_CURRENT_SOURCE_DIR}/doxygen.cfg.in
     ${CMAKE_CURRENT_BINARY_DIR}/doxygen.cfg @ONLY)
 
@@ -73,7 +65,6 @@ if (LLVM_ENABLE_DOXYGEN)
   set(bolt_doxygen_qhelpgenerator_path)
   set(bolt_doxygen_qhp_cust_filter_name)
   set(bolt_doxygen_qhp_cust_filter_attrs)
-  set(DOT_IMAGE_FORMAT)
 
   add_custom_target(doxygen-bolt
     COMMAND ${DOXYGEN_EXECUTABLE} ${CMAKE_CURRENT_BINARY_DIR}/doxygen.cfg

bolt/docs/doxygen.cfg.in

@@ -2210,7 +2210,7 @@ DIRECTORY_GRAPH        = YES
 # The default value is: png.
 # This tag requires that the tag HAVE_DOT is set to YES.
 
-DOT_IMAGE_FORMAT       = @DOT_IMAGE_FORMAT@
+DOT_IMAGE_FORMAT       = svg
 
 # If DOT_IMAGE_FORMAT is set to svg, then this option can be set to YES to
 # enable generation of interactive SVG images that allow zooming and panning.

clang-tools-extra/docs/CMakeLists.txt

@@ -46,14 +46,6 @@ if (DOXYGEN_FOUND)
       set(clang_tools_doxygen_qhp_cust_filter_attrs "")
     endif()
 
-    option(LLVM_DOXYGEN_SVG
-      "Use svg instead of png files for doxygen graphs." OFF)
-    if (LLVM_DOXYGEN_SVG)
-      set(DOT_IMAGE_FORMAT "svg")
-    else()
-      set(DOT_IMAGE_FORMAT "png")
-    endif()
-
     configure_file(${CMAKE_CURRENT_SOURCE_DIR}/doxygen.cfg.in
       ${CMAKE_CURRENT_BINARY_DIR}/doxygen.cfg @ONLY)
 
@@ -71,7 +63,6 @@ if (DOXYGEN_FOUND)
     set(clang_tools_doxygen_qhelpgenerator_path)
     set(clang_tools_doxygen_qhp_cust_filter_name)
     set(clang_tools_doxygen_qhp_cust_filter_attrs)
-    set(DOT_IMAGE_FORMAT)
 
     add_custom_target(doxygen-clang-tools
       COMMAND ${DOXYGEN_EXECUTABLE} ${CMAKE_CURRENT_BINARY_DIR}/doxygen.cfg

clang-tools-extra/docs/doxygen.cfg.in

@@ -2205,7 +2205,7 @@ DIRECTORY_GRAPH        = YES
 # The default value is: png.
 # This tag requires that the tag HAVE_DOT is set to YES.
 
-DOT_IMAGE_FORMAT       = @DOT_IMAGE_FORMAT@
+DOT_IMAGE_FORMAT       = svg
 
 # If DOT_IMAGE_FORMAT is set to svg, then this option can be set to YES to
 # enable generation of interactive SVG images that allow zooming and panning.

clang/docs/CMakeLists.txt

@@ -47,14 +47,6 @@ if (LLVM_ENABLE_DOXYGEN)
     set(clang_doxygen_qhp_cust_filter_attrs "")
   endif()
 
-  option(LLVM_DOXYGEN_SVG
-    "Use svg instead of png files for doxygen graphs." OFF)
-  if (LLVM_DOXYGEN_SVG)
-    set(DOT_IMAGE_FORMAT "svg")
-  else()
-    set(DOT_IMAGE_FORMAT "png")
-  endif()
-
   configure_file(${CMAKE_CURRENT_SOURCE_DIR}/doxygen.cfg.in
     ${CMAKE_CURRENT_BINARY_DIR}/doxygen.cfg @ONLY)
 
@@ -72,7 +64,6 @@ if (LLVM_ENABLE_DOXYGEN)
   set(clang_doxygen_qhelpgenerator_path)
   set(clang_doxygen_qhp_cust_filter_name)
   set(clang_doxygen_qhp_cust_filter_attrs)
-  set(DOT_IMAGE_FORMAT)
 
   add_custom_target(doxygen-clang
     COMMAND ${DOXYGEN_EXECUTABLE} ${CMAKE_CURRENT_BINARY_DIR}/doxygen.cfg

clang/docs/doxygen.cfg.in

@@ -2193,7 +2193,7 @@ DIRECTORY_GRAPH        = YES
 # The default value is: png.
 # This tag requires that the tag HAVE_DOT is set to YES.
 
-DOT_IMAGE_FORMAT       = @DOT_IMAGE_FORMAT@
+DOT_IMAGE_FORMAT       = svg
 
 # If DOT_IMAGE_FORMAT is set to svg, then this option can be set to YES to
 # enable generation of interactive SVG images that allow zooming and panning.

flang/docs/CMakeLists.txt

@@ -48,14 +48,6 @@ if (LLVM_ENABLE_DOXYGEN)
     set(flang_doxygen_qhp_cust_filter_attrs "")
   endif()
 
-  option(LLVM_DOXYGEN_SVG
-    "Use svg instead of png files for doxygen graphs." OFF)
-  if (LLVM_DOXYGEN_SVG)
-    set(DOT_IMAGE_FORMAT "svg")
-  else()
-    set(DOT_IMAGE_FORMAT "png")
-  endif()
-
   configure_file(${CMAKE_CURRENT_SOURCE_DIR}/doxygen.cfg.in
     ${CMAKE_CURRENT_BINARY_DIR}/doxygen.cfg @ONLY)
 
@@ -73,7 +65,6 @@ if (LLVM_ENABLE_DOXYGEN)
   set(flang_doxygen_qhelpgenerator_path)
   set(flang_doxygen_qhp_cust_filter_name)
   set(flang_doxygen_qhp_cust_filter_attrs)
-  set(DOT_IMAGE_FORMAT)
 
   add_custom_target(doxygen-flang
     COMMAND ${DOXYGEN_EXECUTABLE} ${CMAKE_CURRENT_BINARY_DIR}/doxygen.cfg

flang/docs/doxygen.cfg.in

@@ -2208,7 +2208,7 @@ DIRECTORY_GRAPH        = YES
 # The default value is: png.
 # This tag requires that the tag HAVE_DOT is set to YES.
 
-DOT_IMAGE_FORMAT       = @DOT_IMAGE_FORMAT@
+DOT_IMAGE_FORMAT       = svg
 
 # If DOT_IMAGE_FORMAT is set to svg, then this option can be set to YES to
 # enable generation of interactive SVG images that allow zooming and panning.

lldb/docs/doxygen.cfg.in

@@ -1571,7 +1571,7 @@ DIRECTORY_GRAPH        = YES
 # generated by dot. Possible values are png, jpg, or gif
 # If left blank png will be used.
 
-DOT_IMAGE_FORMAT       = png
+DOT_IMAGE_FORMAT       = svg
 
 # The tag DOT_PATH can be used to specify the path where the dot tool can be
 # found. If left blank, it is assumed the dot tool can be found in the path.

llvm/docs/CMake.rst

@@ -469,9 +469,6 @@ enabled sub-projects. Nearly all of these variable names begin with
   combination with ``-DLLVM_ENABLE_DOXYGEN_QT_HELP=ON``; otherwise
   it has no effect.
 
-**LLVM_DOXYGEN_SVG**:BOOL
-  Uses .svg files instead of .png files for graphs in the Doxygen output.
-  Defaults to OFF.
 
 .. _llvm_enable_assertions: