Usage code for finding CFA

eh_frame.c

@@ -200,7 +200,7 @@ iterate_call_frame_instructions(u8 *data, u64 to_read)
 }
 
 static u64
-read_one_cie(struct dwarf_cie_header *header, u64 length, u8 *data, u8 *original_data)
+read_one_cie(struct dwarf_cie *header, u64 length, u8 *data, u8 *original_data)
 {
     header->length = length;
     header->version = *data++;
@@ -261,7 +261,7 @@ read_one_cie(struct dwarf_cie_header *header, u64 length, u8 *data, u8 *original
 }
 
 static u64
-read_encoded_pointer(struct mi_process proc, struct dwarf_cie_header *cie, u8 *data, u64 *dest)
+read_encoded_pointer(struct mi_process proc, struct dwarf_cie *cie, u8 *data, u64 *dest)
 {
     u64 offset = 0;
     s64 final_value;
@@ -338,9 +338,6 @@ read_encoded_pointer(struct mi_process proc, struct dwarf_cie_header *cie, u8 *d
         }
     }
     
-    struct mi_registers regs = get_process_registers(proc);
-    struct mi_function *func = get_function_around_pc(proc, regs.rip - proc.base_address);
-    
     switch (cie->pointer_application) {
         case DW_EH_PE_pcrel: {
             *dest = data - proc.elf + final_value;
@@ -366,17 +363,8 @@ read_encoded_pointer(struct mi_process proc, struct dwarf_cie_header *cie, u8 *d
             break;
         }
         
-        case DW_EH_PE_funcrel: {
-            if (func) {
-                *dest = func->low_pc + final_value;
-            } else {
-                DIE("could not find function around pc while decoding address!\n");
-            }
-            break;
-        }
-        
         default: {
-            DIE("unsupported pointer application: DW_EH_PE_aligned, DW_EH_PE_indirect, or DW_EH_PE_omit\n");
+            DIE("unsupported pointer application: DW_EH_PE_funcrel, DW_EH_PE_aligned, DW_EH_PE_indirect, or DW_EH_PE_omit\n");
         }
     }
     
@@ -384,12 +372,12 @@ read_encoded_pointer(struct mi_process proc, struct dwarf_cie_header *cie, u8 *d
 }
 
 static u64
-read_one_fde(struct mi_process proc, struct dwarf_cie_header *cie, u64 length, u32 cie_offset, u8 *data, u8 *original_data)
+read_one_fde(struct mi_process proc, struct dwarf_cie *cie, u64 length, u32 cie_offset, u8 *data, u8 *original_data)
 {
-    struct dwarf_fde_header header = { 0 };
+    struct dwarf_fde header = { 0 };
     
     header.length = length;
-    header.cie = (struct dwarf_cie_header *) (data - 4 - cie_offset);
+    header.cie = (struct dwarf_cie *) (data - 4 - cie_offset);
     
     u32 pointer_size = read_encoded_pointer(proc, cie, data, &header.low_pc);
     data += pointer_size;
@@ -414,14 +402,13 @@ read_one_fde(struct mi_process proc, struct dwarf_cie_header *cie, u64 length, u
         data += header.augmentation_data_length;
     }
     
-    struct dwarf_cie_header hh = { 0 };
     data += iterate_call_frame_instructions(data, header.length - (data - original_data - 4));
     
     return(data - original_data);
 }
 
 static u64
-read_one_call_frame_record(struct mi_process proc, struct dwarf_cie_header *last_cie, u8 *data)
+read_one_call_frame_record(struct mi_process proc, struct dwarf_cie *last_cie, u8 *data)
 {
     u8 *original_data = data;
     u64 length;
@@ -460,7 +447,7 @@ static void
 parse_eh_frame(struct mi_process proc)
 {
     struct elf_section_table_entry_x64 eh_frame = get_section_entry(proc.elf, ".eh_frame");
-    struct dwarf_cie_header last_cie = { 0 };
+    struct dwarf_cie last_cie = { 0 };
     
     u64 read = 0;
     
@@ -471,4 +458,27 @@ parse_eh_frame(struct mi_process proc)
             break;
         }
     }
+}
+
+static struct dwarf_fde *
+eh_frame_find_fde(struct mi_process proc, u64 pc)
+{
+    
+}
+
+static struct dwarf_regset
+eh_frame_init_registers(struct mi_process proc, struct dwarf_cie *cie)
+{
+    
+}
+
+static struct dwarf_regset
+eh_frame_find_pc(struct mi_process proc, struct dwarf_fde *fde, struct dwarf_regset regs, u64 pc)
+{
+    
+}
+
+static u64
+eh_frame_compute_cfa(struct mi_process proc, struct dwarf_regset regs)
+{
 }

elf_dwarf.h

@@ -641,7 +641,7 @@ struct dwarf_line_number_state {
     u32 discriminator;
 };
 
-struct dwarf_cie_header {
+struct dwarf_cie {
     u32 length;
     u8 version;
     u32 code_alignment;
@@ -649,20 +649,25 @@ struct dwarf_cie_header {
     u32 return_address_register;
     u32 augmentation_data_length;
     u8 *augmentation_data;
+    u8 *instructions;
     
     int has_z;
-    
     enum dwarf_cie_pointer_format pointer_format;
     enum dwarf_cie_pointer_application pointer_application;
     u8 pointer_indirect;
 };
 
-struct dwarf_fde_header {
+struct dwarf_fde {
     u32 length;
     u64 optional_length;
-    struct dwarf_cie_header *cie;
+    struct dwarf_cie *cie;
     u64 low_pc;
     u64 high_pc;
     u32 augmentation_data_length;
     u8 *augmentation_data;
+    u8 *instructions;
+};
+
+struct dwarf_regset {
+    s64 cfa;
 };

main.c

@@ -1,8 +1,8 @@
 #include "common.h"
 
-#include "util.c"
 #include "dwarf.c"
 #include "eh_frame.c"
+#include "util.c"
 #include "command.c"
 
 int

util.c

@@ -298,12 +298,17 @@ get_function_around_pc(struct mi_process proc, u64 pc)
     return(0);
 }
 
-#if 0
 static u64
 get_cfa_at_pc(struct mi_process proc, u64 pc)
 {
-    u64 *at = eh_frame_find_fde(proc, pc);
-    struct dwarf_regset regs = eh_frame_init(at);
-    u64 result = eh_frame_find_pc(at, regs, pc);
-}
-#endif
+    struct dwarf_fde *fde = eh_frame_find_fde(proc, pc);
+    if (!fde) {
+        DIE("could not find FDE for pc!\n");
+    }
+    
+    struct dwarf_regset regs = eh_frame_init_registers(proc, fde->cie);
+    regs = eh_frame_find_pc(proc, fde, regs, pc);
+    u64 cfa = eh_frame_compute_cfa(proc, regs);
+    
+    return(cfa);
+}